CONTENTS.

PART I.—Ocroper, 1904.

. Biscayan Plankton collected during a Cruise of H.M.S. ‘ Research, 1900.—

Part I. Mreruops anp Dara. (Plate 1.) DB, y G. Hersert Fowter, B.4.,

SEES 3 s ; lt ME ew ee he «Cs pages 1-11

PART II.—Novemper, 1904.

. The Amphipoda and Cladocera, with Notes on a Larval Thyrostracan. by the

Rev. T. R. R. Srepsine, A., VRS. PLS. F.Z.S., and an Appendix on

their Distribution by G. Herserr Fowurr, B.A., Ph.D, PLS, F.ZS.

Pereeoreon ie: . . |. RM ew we «LB

PART III.— January, 1905.

. The Chetognatha. By G. Herserr Fowrer, B.A. Ph.D. PLS, F.Z.S.

Beene (uine?s . . . MI ae BO -87

PART IV.—NovempBer, 1905.

. The Thaliacea. By G. Herserr Fowier, B.A., Ph.D., F.L.S., F.Z.8. (Plates

ete eke el .. BOLO

. The Schizopoda. By EB. W. L. Horr and W. M. Tarrersaty, B.Se. (with Text-

figures). With an Appendix by G. Herserr Fowter, B.d., PhD, FLS.,

ea i ec a ee DOD

. The Colloid Radiolaria. By R. Norris Wotrenpen, UD, F.LS,

DUES gs ee Ee iene es Ld ts

PART V.—FeEsrvuary, 1906.

. Mollusca (excluding Cephalopoda). By Pauu PEtsenker, Professeur & UEcole

Normale de Gand. (Communicated with a Note on theix Distribution by

G. Hersert Fow.rer, B.A., Ph.D, PLS., F.Z.S.) (Plates 10-12.). 137-157

seo43

PART VI.—OcrToseEr, 1906.

VIII. The Cephalopoda. By Dr. W. E. Woyie, Director of the Manchester Museum.

(Communicated by Dr. G. H. Fowier, F.Z.S.) (With 3 Text-figures.) 159-162

IX. The Meduse. By Epwarp 'T. Browne, b.A., Zoological Research Laboratory,

University College, London. (Communicated by Dr. G. Herbert Fowier,

F:i.S.) (Plate 18.). 2 02 22. SR

PART VII.—May, 1907.

X. The Fishes. By ¥.W.U. Hour and 1. W. Byrne. (Communicated by Dy. G.

Herpert Fowier, F.L.S. [with Note to the foregoing Report by the

8UME]) ne cow oh BP a Rg le eae ee

PART VIII.—OcroseEr, 1907.

XI. Decapoda. By Svantey W. Kemp, B.A. (Communicated by Dr. G. HerBerr

Fowurer, F.L.S. {with Note on Distribution by the same]). (Plates 14 & 15.)

205-217

PART ILX.—NovemBeEr, 1909.

XII. The Ostracoda. By G. Herpert Fow er, B.A., PAD, FLS. FZS.

(Plates 16-27.) °.. 2 2s - + 2% GARR Ge

PART X.—Jvnp, 1911.

XIII. The Siphonophora. By Henry B. Bicetow, Museum ef Comparative Zoology,

Cambridge, Mass. (Communicated by G. H. Fowuer, B.A., Phw)., FLS.,

FZ.S.) (Plate 28.) 2) 0. SRS

PART XI.—Jtnpn, 1922.

Titlepage, Contents,and Index . . . . . . . «. 2 «.% = 5 « = 9 ORES

ThA NS AGELO NS

Pree LINNEAN SOCEEL Y,

BESCAY A Ne eipA NK TON

COLLECTED DURING A CRUISE OF H.M.S. ‘ RESEARCH,’ 1900.

Part I.—METHODS AND DATA.

(Plate 1.)

By G. HERBERT Fow eR, B.A., Ph.D., F.LS., F.Z.S.

Read 21st January, 1904.

DURING the month of J uly, 1900, the Lords Commissioners of the Admiralty

consented, at the request of the Council of the Royal Society, to place H.M.S. ‘ Research’

at my disposal for an investigation of the Plankton of the Bay of Biscay. In this work

I had the very great advantage of the voluntary assistance of my friend Mr. L. A.

Borradaile, of Selwyn College, Cambridge, without which it would have been impossible

to get through so much in the time at my disposal. My thanks are also due not only

to the Lords of the Admiralty and to the Council of the Royal Society, but also to

Admiral Sir W. J. Wharton, F.R.S., for his assistance in the matter, and to Captain A. M.

_ Field and the other officers of the ‘ Research’ for the een and patient help which they

rendered throughout the cruise.

The area studied was selected as being the nearest to Great Britain at which a depth

of over 2000 fathoms could readily be obtained. It lay between 46° 43' and 47° 29' North

latitude, and 7° 15’ and 8° 18’ West longitude. Thestations were included in a parallelo-

gram which measured roughly 78 by 20 nautical miles. Within so small an area, and

at a considerable distance from land, there is no reason to suppose that the fauna and

_ physical conditions are other than uniform throughout; and what is true of one

extremity of the parallelogram may fairly be taken to hold good of the other end at the

same moment. ‘This identity of conditions was deliberately selected, for, as I have else-

where maintained *, accurate information as to the constituents of the Mesoplanktonic

* Proc. Zool. Soc. 1898, pp. 567 et seq.

SECOND SEIMES.— ZOOLOGY, VOL. X. 1

2 DR. G. H. FOWLER—BISCAYAN PLANKTON :

fauna is only possible by a comparison of numerous hauls taken at all depths in the same

area at about the same date.

The special problems, with reference to which the hauls were planned, were (1) the

vertical movement of the Epiplankton in relation to time of day, and, if possible, to such

other varying conditions as rain, wind, and swell; (2) the presence (or absence) in deep

colder water of organisms known to occur at the surface in higher latitudes, but not

represented in the warmer surface-waters of the Bay of Biscay. Until the Reports on

the various groups of animals are finished, it will be impossible to say how far the

attempt on these two problems has been successful; but I venture to think that a glance

at the table of hauls below (pp. 8-10) will show that a serious attempt has been made to

attack them. In this first communication those working data of the cruise are published

which will make subsequent Reports intelligible.

The methods of collection employed were: (1) ordinary open tow-nets (about

20 inches diameter, except net 180 which was 12 inches in diameter) towed by the

ship’s drift at the surface and at depths of 25, 50, 75, and 100 fathoms; (2) the opening

and closing Mesoplankton net which had been previously used with success by myself in

the Feeroe Channel, and by the Dutch ‘Siboga’ Expedition in the Hast Indies *; (8) a

Mesoplankton trawl, differing only from the latter in having a 4-foot-square mouth, and

a bag made of pilchard-netting, 9 feet in length, but with the same arrangements for

opening and closing ; (4) at the close of the cruise, open tow-nets bent on to a wire rope

at intervals between 100 and 350 fathoms, after the serial method in use on H.M.S.

‘Challenger, for comparison with what I regard as the more certain method of a closing

net. So far as I have observed, while the serial method brings on deck a very much

larger quantity of material, its condition is often not so good as that from the closing nets.

On the question of the nets, some of my results may perhaps prove of use to other collectors on

board ship.

(1) With hauls at the actual swrface (since a long line is necessary to let the net go clear of the ship’s

refuse, and clinkers and potato-parings do not improve the Plankton) hemp rope and a float where the

bridles of the net are attached to it, give the best results: even a fine wire has a tendency to sink the

net to an uncertain depth, and wet cod-line cuts the hands painfully when hauled. With deeper Epi-

plankton hauls, down to 100 fathoms a small hand-winch and fine wire rope with a 19 lb. lead at the

end gave excellent results; but even with this weight the nets have a tendency to stream upwards and

away from the vertical, and in drifting before a strong wind a net at the end of a 100-fathom wire may

have towed anywhere between 100 and 70 fathoms. If the angle made by the visible wire, which may

be 45° in a strong drift, were constant for the whole length of the wire, then

the 100-fathom mark would be at 70 fathoms,

»” 75 2» 2» 52 ” .

” 50 » ” 39 ”

” 25 ” ” 17 ”?

In using two nets at a time on the wire, and a 20 lb. lead, it is safer, except in a flat calm, to bend the

nets on, not at the 100, 75, &c. marks, but at from 5 to 10 fathoms below these marks ; it is better to

* «Siboga’ Expeditie: Introduction et Description de l’Expédition, par Max Weber, p. 11. I may perhaps be

pardoned for remarking that Prof. Weber speaks well of the net,

METHODS AND DATA. 3

go too deep than too shallow. At the same time, as I have before shown*, the angle made by the

visible wire in going over is not an accurate indication of the he of the submerged wire: for example,

during this cruise, on one occasion (hauls 35 ¢ and d) my nets, streamed from the port quarter, fouled a

sounding-wire with thermometers let go from the starboard bow ; on discovering the foul, both wires

were hauled, and both appeared to be straight up and down for many fathoms, although really foul of

one another at 70 fathoms depth under the keel amidships.

Two attempts to improve the ordinary tow-nets are perhaps worth recording, although both were

failures, since they may serve as warnings to other marine naturalists. In the one, a funnel of boulting-

cloth hung down loosely into the net from the frame, to serve as a “pocket” which should keep the

faster swimmers from escaping ; its effect. in practice was to prevent animals from getting into the net by

diminishing the opening, rather than to keep them there. Another experiment was a funnel of boulting-

cloth, which was fastened to the net just above the collecting-tin, the lower end hanging in the tin, with

the idea of saving the organisms which get crushed in the angle between net and tin when the latter is

lifted out of water; it was not a success.

(2) The Mesoplankton net, which was fully described inthe Proc. Zool. Soc. for 1898, pp. 568-574,

worked fairly well, but with 23 per cent. of failures: these were traced to easily remediable causes,

notably to the net-frame being too light for the lock, if lowered fast or used in a heavy swell : these

defects have been remedied in nets built subsequently for the Antarctic ship ‘ Discovery’ and for

Dr. Wolfenden.

(3) The Mesoplankton trawl, having a much heavier net-frame, worked quite satisfactorily as a

machine, but caught so little, in comparison with the time occupied on deep hauls, that it was soon

abandoned. It had been devised to catch large organisms, fish, and cephalopods, which escape the

ordinary net owing to its small size and slow speed. I attribute its failure to catch more than it did, to

its being still too small and hauled too slowly ; it could only be heaved in at about 2 miles an hour,

the maximum rate at which the winch hands could reel up the wire rope as delivered from the deck-

engine. When touched, large animals seem to jump clear of a small net: I have therefore designed a

17-foot-square trawl to open and shut, which I hope may yield better results, if the winch is geared to

the deck-engine.

The epiplankton nets were out for different periods of time, generally for about an hour. I think

that uniform hauls of half an hour would have been better. In an hour more material is, of course,

caught ; but it seems to increase the number of specimens rather than of species, with the results that

the condition of the material is not so good, and that the labour of sorting the catch, always tedious,

becomes doubly so. In consequence, I have taken for identification only about half the material in

many of the epiplankton hauls; from the other half have been taken conspicuous novelties, and

organisms of which every specimen was desired for statistical (quantitative) study.

As regards reagents for dealing with the bulk of the eatch, which remains when the larger specimens

have been picked out, the chief thing to avoid is mercury bichloride: this forms a dirty, sticky, insoluble

deposit all over the specimens, apparently consisting of an albuminous compound with mercury. My

_ best results, on the whole, were got by adding a little pure formalin to kill, and when the animals had

sunk to the bottom of the jar, by preserving in 3 per cent., followed by 5 per cent. solution of formalin

in fresh water.

- The details in Table I. are extracted from the ship’s log. The force of the wind is

expressed on Beaufort’s scale, of which

1 represents a velocity of 8 miles per hour,

2 » » oe S,

3 ”? ” 18 ”) »

4 ” ” 23 ” ”

* Proc. Zool. Soc. 1898, p. 568,

4, DR. G. H. FOWLER—BISCAYAN PLANKTON:

As regards the state of the sea, it must be remembered that “smooth ” in a sailor’s

mouth often covers enough swell to break Medusee and Siphonophora to bits in the net,

and to make it difficult to work deep-water nets.

The depths marked with a + were the greatest depths to which a net was lowered

each day and found no bottom.

In Table II. are given the more variable data.

All the hauls were made with open tow-nets, except where only the time of arrival

on board is given in the second column, these hauls being taken with the closing Meso-

plankton net.

In the third column, headed ‘‘ Net,”’ is given the number of meshes per linear inch:

a matter of importance in dealing with minute animals. The nets were made of the

ordinary Swiss Boulting Silk familiar to marine zoologists (except 65, which was of

muslin),

The fourth column shows the horizon investigated. In the hauls marked 25, 50, 75, &e.

to 0, the net was lowered, towed for some time at the lowest level, and pulled straight up

to the surface again as rapidly as was safe. As has been pointed out above, these nets

may have towed a little above the depth indicated, in some cases where the ship’s drift

was considerable ; but I do not think that, used as they were on a }" circumference wire

rope with a 19-Ib. sounding-lead, they are likely to have risen much above the theoretical

depth.

As regards the deeper hauls, there were in the regular series :

7 hauls from 200 to 100)

3 = eee woo, 200

3 i ” 400 ,, 300 f 10Cnsae sections,

Bo eeeeswes,, 400

ay PegoO,, 500)

1000 ,, 750 \

1250 ,, 1000 |

1500 ,, 1250J

2000 ,, 1500 500-fathom sections ;

250-fathom sections,

~w WwW KW or

and also as extra hauls round a supposed “ critical *’ depth, there were :

)

1 haul from 150 to 50,

1 55 5, 150 75,00}

Smhaulsie.,, 260) 1 elb0:

The collection may therefore be expected to yield a fair picture of the smaller Meso-

plankton.

The actual bulk of water from which the fauna is strained by these deep-water

nets is very small; and this point must not be forgotten when organisms are only occa-

sionally captured, or seem few and far between in the deeper hauls. Thus with the

ordinary 20-inch-square Mesoplankton net in the tables just given :

100-fathom section strains 1650 cubic feet,

po vemae: > , gles eevee

500 . + 8950 ee oe

of which even the last is less than the cubic contents of a fair-sized drawing-room,

20'« 30! x 14! high.

METHODS AND DATA. 5

Ss The total number of what I term ‘comparable hauls’’ with tow-nets is made up

as follows :—

25 hauls at O fathoms)

12 25 el

13 a 50 a Epiplankton hauls

» .. ° {with open tow-nets.

1 oe vo ” |

22 5, AO)

7 » Various depths, open serial tow-nets.

37 sD 55 D closing Mesoplankton net.

127

These omit as “non-comparable” from the list in Table II., two hauls of which only

part was kept (21d, 21 d'), two miss-fires of the Mesoplankton net (27a, 27 a’), three

hauls of the trawl (29 a, 30 a, 30 e), and four hauls of which the specimens cannot at the

~ moment be traced (¢f. p. 11).

As regards the temperatures, we depended on the daily observations in the ship’s

log for the surface records. But as a Quartermaster’s readings of a thermometer are not

invariably accurate, I have generally taken a mean for each day as the safest approxi-

mation, and as sufficiently useful for zoological, although not for meteorological, work.

As regards the temperatures at 25, 50, and 75 fathoms, I regret to say that in the

constant calls on my time in connection with the rest of the work, I entirely forgot to

take any observations! The temperatures for these depths have, however, been

supplied as mean values for July in this district by the kindness of Dr. Schott, of the

_ Deutsche Seewarte in Hamburg.

_ The deep-sea temperatures are taken from a very complete series of observations which

the officers of H.M.S. ‘Research’ were kind enough to make for me at the time. The

thermometers used were of the Miller-Casella type, and included some special ones with

a scale of twice the usual size. They were used on sounding-wire ; attempts to use the

33; diam. wire rope showed that the vibration of the rope jarred the indices down and

rendered observations quite unreliable.

_ The actual observations were as follows, omitting those on the wire rope :—

Depths in Fathoms: Temperatures in Degrees Fahrenheit.

es, | 5 batons. [eae] Te iy diaeaa)

| Fathoms ...| 100 | 200 | 250 | 300 | 350 | 400 | 450 | 500 | 550 | 600 | 700 | 800 | 900 1000 oP ea agi 1250 1500 1750 2000 2541,

eee |

(duly {527/619 ... [5181 ... [5051 ... [500] ... [4861 47-5] 45-7| 49-51 4061 ... [900] ... | ... [385/974 84| 366)...

Siew, ...| ... [520] 51-7)/51-5|508) 50-4)... | | ane | one | owe | oe Wel Shs |e | sss. aes ee Jw |e] |

ae, ..| ... | sa hts eae Ae lass]

piethy,, ..| ... |... | ... {51-2} 50:8] 505] 498] 49-4/ 489]... |... |. | we |. 308)... |

| jelabe

39:0) 38°8) ...

. |46°8) ... | 41-7) 40:0 39°F) 39:2, 38°6 38°5) ...

__ These observations have been plotted into the curve marked I. in Pl. 1, Alongside of

: this has been plotted a curve, marked II., deduced from the much scantier observations

6 DR. G. H. FOWLER—BISCAYAN PLANKTON:

of H.M.S. ‘ Porcupine,’ Station 38, 1869, position 47° 39’ N., 11° 33’ W., or about

150 miles W.N.W. of our usual position *; and the curve of mean ocean temperatures +

has been placed alongside as ITI.

This last curve, plotted, as Dr. Buchan said, “from the whole of the observations in

all latitudes for the different depths” recorded up to the date of his Report, may be

taken as the standard curve for ocean temperatures where unaffected by specific causes.

But curves I. and II.,as compared with the regularity of III., show by a downward bow

that between 200 and 1000 fathoms the water is much warmer than it should be

according to the usually regular diminution of temperature. This is no doubt due

largely to the influence of the Gibraltar bottom current. At the Straits of Gibraltar

there is an upper inflow of colder water from Atlantic to Mediterranean, and a bottom

outflow of warmer water from Mediterranean to Atlantic } : the influence of this warmer

water is very conspicuous in the maps appended to Dr. Buchan’s ‘Challenger’ Report,

already cited, between 500 and 900 fathoms, as shown by a concentricity of the isobathy-

therms at these and intermediate depths with Gibraltar as a centre §. That the critical

points of the *‘ Porcupine’ curve are at higher horizons than those of the ‘ Research’

curve, and that the curve as a whole is colder, is probably due to the more northerly

position of the ‘ Porcupine’ station and its greater distance from Gibraltar.

The letters in the sixth column under the head of “‘Weather 7? are taken from

Beaufort’s scale, and are as follows :—--

B = blue sky. O = overcast.

C = cloudy. R = rain.

M = mist.

Under the heading of * Light ’’ in the log is recorded the number of seconds required

to turn the sensitive paper of Wynne’s Exposure Meter toa standard tint. This method

of light-estimation was suggested to me by Mr. E. W. L. Holt: of course it records only

actinic values, not absolute light; unfortunately it is practically useless at dawn and

dusk, and is quite useless at night even when there is a considerable amount of non-

actinic light.

With regard to the occasional presence in a deep haul of isolated specimens of animals captured other-

wise only at higher horizons, it must be noted that while the nets were always washed out in fresh water

after a haul, there is always a possibility of a small animal adhering to the net and appearing in the

collecting-tin of a subsequent haul. Again, an animal froma previous haul may conceivably be left over

on a dipping-tube or im a killing-bottle, and so stray into a later haul, in the haste which is often

* Wyville Thomson: Depths of the Sea, pp. 143 & 321.

+ A. Buchan: ‘Challenger’ Report on Oceanic Circulation, p. 9.

+ ‘Shearwater,’ Proc. Roy. Soc, xx. p. 97.

§ This explanation has also been accepted within certain limits by Dr. Gerhard Schott (‘ Valdivia’ Expedition,

Oceanographie, p. 186).

METHODS AND DATA. 4

inseparable from work of this kind at sea. However, with reasonable care such cases will be few in

number, and will not materially affect the question of large percentages.

In some groups (Chetognatha, Ostracoda, &c.) an attempt will be made to give a quantitative

estimate of the specimens captured, with a view to the study of their vertical oscillation. It is not

contended that every single specimen of a minute Ostracod or Doliolwm has been picked out of the more

abundant hauls; the clots which Phzodarian Radiolarians often make, which cannot be disentangled

without wrecking the specimens, are alone enough to prevent this—still, it has been attempted. The

population-figures presented will therefore not be absolutely accurate, but will be, I believe, fairly

proportionately correct. In any case, the error is greatest in the more populous hauls, and falls to

zero in the less populous; its result will therefore be to underestimate the difference between abundance

and scarcity of a species—if the figures were absolutely correct, the argument from the numbers

captured would be stronger.

On pages 53, 54 will be found examples of a “ time-depth ” table, issued to the natu-

____ ralists who are kind enough to report upon individual groups. It was drawn primarily

___ with the idea of seeing whether a species rises by night and sinks by day, or not; but it

serves also, as in these first instances, to exhibit graphically the horizons of capture in

the Epiplankton and upper Mesoplankton. The ordinates are the twenty-four hours, the

abscissze are depths down to 4.00 fathoms (not proportional). Every “‘comparable” haul is

set down at or near its intersection point, and the hauls in which a species was captured

are printed in heavy type. All these hauls were made with open tow-nets, and ended at

the surface, except those over which an arrow is placed: these latter were made with

the closing Mesoplankton net, the length of the arrow indicating the section through

_ which the net was open. Thus 32/ was a haul with the Mesoplankton net open

between 400 and 300 fathoms, but 36/7 began at 350 fathoms and was open to the

surface.

____ It will be obvious from this table that the Epiplankton hauls were deliberately grouped

round noon and midnight, round the surface and the 100-fathom line, as being supposed

_ to be “critical.” There is no reason to believe that the “ diurnal ” conditions, which have

_ been alleged to produce a vertical oscillation of the Plankton, differ appreciably between

(say) 6.0 a.m. when the sun is well up, and 6.0 p.m. when he has lost his power;

aa i must not close this introduction without expressing my indebtedness for much practical help in

Z matters of gear to Mr. W. P. Bullivant (Messrs. Bullivant and Co.), and to Mr. M. H. Gray (Telegraph

Works Company, Silvertown).

8 DR. G. H. FOWLER—BISCAYAN PLANKTON :

TABLE I.

Position. Wind. Observed

Hauls. Date. = Baa. bare

| N. latitude. | W. longitude.} Direction. Force. fathoms.

Diastolic). =| davai. Ni fey Gee N. by E. 2 Smooth. +2000

| PAL Ch ey AG oly teknetls 47° 4! 7° 53! N.E. 2 ey

\21kto 22g ..| Ovi] 47° 11' 8°11’ ESE. Bes 4

|23ato23e ..|10.vii. A7° 29' 8° 18’ S.E. 3 Slight swell. 1219

24ato 24k ..|11.vil. 47° 5! aloy! N.E. 3} Smooth. 2341

195 ato 251 ..|12.vii. 46° 59' 7° 46' N.N.W.toN.| 1-2 Calm. +2000

126ato26f ..| 13.vii. 46° 59' 7° 29' S.W. 2-4. Smooth, with occa- | +2000

|\27ato27c¢ ..|14.vil. 46° 54’ Th OXY S.W. 1 } sional large swells. | +1250

ONG mcg ake 18.vii. Ae 29! 7° AA! E. 3 Shght swell. +1750

130 ato 30m ..|19.vii. 47° 14’ oot S.S.W. 2 Smooth. +2000

8lato 31d ..|20.vii. 47° 15 COAL W. 2-4 Moderate swell. +1250

|382ato 32» ..| 21.viL 47° 0! (aks) S.W. 0-1 Slight swell. +1000

|383.ato 33h ..| 22.vii. Ale 2) (ees INES 1 Moderate swell. + 750

| 34a to 34h ..| 23.vii. 46° 43' (Psy N.E. 1-2 Smooth. + 750

| 385ato35y ..| 24.vii. 47° 8 foe E. to N.E. 1=2 = +1200

|36ato367 ..|25.vii.| 47° 3) 7° 55! NE 1 :

TABLE IT.

= Horizon, Temperature: Light,

Haul Hour. Net in fathoms. F See hcit, Weather. in cs

| Dray 2 Grek: arr. 12.15 p.m. 45 200 to 0 52 to 61 Bie |

ROL eens | arr. 4.0 Pm. 36 200 to 100 52 BC. |

NH) Wika Sek aes arr. 5.50 P.M. 36 300 to 200 51 to 52 BC

Weel imager 9.15 a.m. Wey i 100 to 0 52 to 62 OC Wl

Webroot, 11.30 a.m. 18 100 to 0 52 to 62 B 2

HDi seep | 1.30 to 2.0 p.m. 60 0) 62 B 2

WANs Rear 2.30 to 3.30 P.M. 180 0 62 B 2

Wo Hilics eee 4.0 to 4.30 p.x. 60 | 50 to 0 52 to 62 B 3

)iltipeee as 6.0 to 6.30 p.m. 6GOre | 100 to 0 52 to 62 B 6 to 7

Dilvaeyre « 11.30 p.m. to midnight 18 0 62 B Bright moon,

\?2iLNemeees arr. 12.0 noon 36 400 to 300 50 to 51 BC

Pa temo gta 10.80 to 11.30 a.o. 60 | 100 to 0 52 to 63 B 4

| 21m .... arr. 1.15 P.M. 36-500 to 400 49 to 50 B

Ol eset arr. 1.30 p.m. 36 150 to 100 52 B 4

| Dios eae arr. 2.0 p.m. 36 | 200 to 100 52 B ’

VAD Sas arr, 2.30 P.M. 36 150 to 50 52 B 4

RE 5.'5 al 2.25 to 4.0 p.m. 60 100 to 0 52 to 63 B 4 to 6

tea Nae Re, ao arr. 5.45 P.M. 36 750 to 500 46 to 49 B

|22ct.....| 8.30 to 9.30 p.m. 60 0 63 B

| 22id> 5...) > LOMSitiomlOM Ones 60 0 63 B Bright moon.

leeeie-eiomiene | 10.20 to 10.40 p.m. 180 0 63 B a on

h22ft ....| LOO to Ui Seear 60 0 63 B a a

)22q ....| 11.30 p.m. to midnight 18 0 63 B 35 -

[23a .. ..{ are, 12.15 Par. 36 1000 to 750 40 to 46 B

CBOs wea 2.10 to 3.10 p.m. 60 0 63 BC 3

OIC eer 2.10 to 3.10 p.m. 180 0 63 BC 3

PRG) Sol op 3.20 to 4.20 p.m. 60 0 63 OC 10

DOO mnet 4.40 to 6.0 PM. 60 0) 63 B 6

QA ave arr. 9.30 A.M. 36 1250 to 1000 38 to 40 OC

Haul.

serene

eee eae

METHODS AND DATA,

TaBLe II. (continued).

Hour.

9.30 to 10.30 a.m.

11.30 a.m. to 1.0 p.m.

1.15 to 2.30 p.m.

38.30 to 4.30 p.m.

5.0 to 6.0 p.m.

5.15 to 6.10 p.m.

12.15 p.m. to 1.15 a.m.

»| L215) pe. to. .15 acm.

9.35 to 11.35 a.m.

11.35 a.w. to 12.35 p.m.

arr. 11.45 a.m.

1.45 to 2.45 p.m.

4.0 to5.0 p.m.

arr. 5.0 P.M.

6.30 to 7.30 p.m.

10.30 to 11.30 p.m.

20) to 43.0" Acm.

2.0 to 3.30 a.m.

9.0 to 10.0 a.m.

arr. 10.30 a.m.

10.0 to 11.0 a.m.

arr. 2.0 P.M.

arr. 3.0 P.M.

arr. 4.45 p.m.

arr. 9.10 a.m.

arr. 1.30 P.M.

arr. 5.0 P.M.

arr. 7.40 p.m.

arr. 6.30 P.M.

arr. 6.30 A.M.

8.15 to 9.15 a.m.

9.15 to 10.15 a.m.

9.45 to 10.30 a.m.

arr. 10.30 a.m.

11.0 a.m. to noon

1.0 to 2.0 Pm.

3.30 to 4.30 p.m,

arr. 4.0 p.m.

arr. 6.30 P.M.

10.30 to 11.80 Pp...

10.30 to 11.30 p.m.

..../11.30 p.m. to 12.80 a.m.

11.30 p.m. to 12.30 a.m.

arr. 8.0 a.m.

arr. 5.0 P.M.

4.15 to 5.15 a.m.

4.15 to 4.45 a.m,

5.30 to 6.30 a.m,

5.30 to 6.30 a.m.

arr. 11.30 a.o.

12.30 to 1.30 p.w.

12.30 to 1.45 p.a.

2.30 to 3.30 p.m.

arr. 3.0 P.M.

arr. 7.10 p.m.

Net.

_ SECOND SERIES.—ZOOLOGY, VOL. X.

Horizon, Temperature: | Light,

in fathoms. Fahrenheit. in seconds.

100 to 0 52 to 63 OC 8

0 63 BC 10 to 6:5

100 to 0 52 to 63 133(0) 10 to 65

100 to 0 52 to 63 OC 6-5 to 13

0 63 OR 13

0 63 OR 14 to 22

0 63 OC 14 to 22

4 ee 4 Weak moon.

0 63 BC 6°5 to 2:5

0 63 B 25

2000 to 1500 36 to 37 B

100 to 0 52 to 63 B m5

50 to 0 52 to 63 B 3 to 6

1500 to 1250 37 to 38 B

50 to 0 52 to 63 B T ton

0 63 B 7 to a

0) 63 B Clear moon.

50 to 0 52 to 63 B 3 3

0 63 B ” ”

25 to 0 54 to 63 BC 55

2000 to 1500 36 to 37 BC

50 to 0 52 to 63 BC Ue

100 to 0 52 to 63 C

200 to 100 52 O

300 to 200 51 to 52 O

1250 to 0 38 to 63 OC

1250 to 1000 38 to 40 B

1000 to 750 40 to 46 B

500 to 250 49 to 51 B

1500 to 750 37 to 46 B

25 to 0 54 to 64 B 4 to 3-5

0 64 B 3:5

50 to 0 52 to 64 B Bi)

2000 to 1000 36 to 40 B

75 to 0 52 to 64 B 3

100 to 0 52 to 64 B 3 to 5:5

100 to 0 52 to 64 OC 5

1500 to 1250 37 to 38 OC

750 to 500 46 to 49 Oc

50 to 0 52 to G4 B Clear, but

25 to 0 54 to 64 B no moon.

25 to 0 54 to 64 OCR Duk

50 to 0 52 to 64 OCR 5

1250 to 1000 38 to 40 Oc

1000 to 750 40 to 46 Oc

50 to 0 52 to 64 BC 45 to 13

25 to 0 54 to 64 BC 45 to 13

0 64 BC 45 to 26°5

100 to 0 52 to 64 BC 12 to 13:

25 to 0 54 to 64 BC 12 to 13

1000 to 750 40 to 46 BC

75 to 0 52 to 64 Oc 5

50 to 0 52 to 64 Oc 5

100 to 0 52 to 64 Oc 5)

1000 to 750 40 to 46 Oc

400 to 300 50 to 51 Oc

DR. G. H. FOWLER—BISCAYAN PLANKTON :

TaBLE II. (continued).

& Horizon, Temperature: | Light,

Haul. Hour. Net. in fathoms. Fahrenheit. Weather. in secoudet

32m 10.30 to 11.30 p.m. 65 75 to 0 52 to 64 OC a

32n 10.30 to 11.30 p.m. 60 100 to 0 52 to 64 OC |

BZD eae | midnight to1.15 a.m.) 65 75 to 0 52 to 64 OC |% Very dark.

32 p ..| midnight to 1.30 a.m. 60 100 to 0 52 to 64 OC |

33 a 1.30 to 2.15 a.m. 180 0 65 OC )

BESS cogs 2.30 to 3.0 a.m. 18 0 65 OC Just before dawn.

Shine 6 wae 11.15 a.m. to 12.30 P.m. 60 50 to 0 52 to 65 OC ;

33 d 7.30 to 8.30P.m. | 60 100 to 0 52 to 65 OC

eters. ovens 7.30 to (8:30 Pat, 9) 65 25 to 0 54 to 65 OC

BBii/a Boat 8.30 to 9.30 rm. | 60 50 to 0 52 to 65 OC

BO Us. wiler 8.30 to 9.30 P.M. 65 25 to 0 54 to 65 OC

WBE Aiea eceot 9.45 to 10.30 p.m. 60 75 to 0 52 to 65 OC Dark.

| 844 1.30 to 2.30 a.m. 65 25 to 0 54 to 65 B Very dark,

OAD echoes 1.30 to 2:30 a.m. 60 100 to O 52 to 65 B | but clear.

| 84. 3.0 to 4.0 Am. 65 75 to 0 52 to 65 BC | ae ‘oh

34d 3.0 to 4.0 aa. 60 100 to 0 52 to 65 Bo °) | Grey. touee

BAe ee oie arr. 8.0 A.M. 45 750 to 500 48 to 49 O

| 34 f. arr, 12.45 p.at. 45 750 to 500 48 to 49 O

34g 12.30 to 1.45 p.m. 60 25 to 0 54 to 65 OC

S4h arr. 7.0 P.M. 45 200 to 100 52 OC

SOC a muster 2.30 to 3.30 a.m. 65 75 to 0 52 to 65 OC A

BBO geist 2,30 to 3.30 a.m. 60 100 to 0 52 to 65 oc } Dark to light.

BDIOns ates 3.45 to 4.15 a.m. 65 75 to 0 52 to 65 OC

30 d 3.45 to 4.30 a.m, 60 100 to 0 52 to 65 OC

SDE. ssesie 7.0 to 8.0 a.m. 65 75 to 0 52 to 65 OCM 6:5

SOW: 7.0 to8.0 a.m. 60 100 to 0 52 to 65 OCcCM 6-5

B5gT 8.15 to 9.15 a.a. 60 50 to 0 52 to 65 OCcCM 65

35h arr. 8.10 a.m. 45 500 to 400 49 to 50 OCM

SO rete ele arr. 9.30 a.m. 45 500 to 400 49 to 50 OC M

3a kk arr. 10.45 a.m. 45 400 to 300 50 to 51 OCM

OO Lanse arr. 12 noon 45 300 to 200 51 to 52 OCM

35 m arr. 12.35 p.m. 45 200 to 100 52 OCM

35 0 arr. 2.15 p.m. 45 200 to 100 52 OCM

BOO. ne arr. 3.15 P.M. 45 250 to 150 52, OCM

35 p arr. 4.15 p.m. 45 250 to 150 2 OCcCM

30s arr. 5.15 P.M. 45 250 to 150 52 OCM

ODES arr. 6.5 P.M. 45 200 to 100 57) OCM

35 w 6.0 to 6.55 P.M. 60 25 to 0 54 to 65 OCM a) Too little to be

35 x 7.0 to 8.0 p.m. 60 100 to 0 52 to 65 OCM > recorded by the

35 y as 7.0 to 8.0 P.M. 65 75 to 0 52 to 65 OCM |) actinometer.

36a .{11.30 p.m. to 12.30 a.m. 65 75 to 0 52 to 66 Oc

33 Ddoo0 46 11.30 p.m. to 12.30 a.m. 60 100 to 0 52 to 66 Oc

Bbc eee 12.45 rato 14540) | 65 25 to 0 BA to 66 OC Vere

36 d (12.45 p.m. to 1.45 a.m. 60 50 to 0 52 to 66 OC

Bble.c. ee 9.15 to 11.45 a.m. 65 100 to 0 52 to 66 OC a}

Obyuem eee 9.15 to 11.45 a.m. 60 150 to 0 52 to 66 OC

369 9.15 to 11.45 a.m. 45 200 to 0 52 to 66 OC

36h 9.15 to 11.45 a.m, 36 250 to 0 52 to 66 OC 5 to 4

Sia ain 12.30 to 2.30 p.m. 60 250 to 0 52 to 66 Oc

36k 12.30 to 2.30 p.m. 45 300 to 0 51 to 66 OC |

OO aeniens 12.20 to 2.30 p.m. 36 350 to 0 50 to 66 OC J

METHODS AND DATA. 10

NOTES TO TABLE II.

Hauls marked with a + are not reckoned as “ comparable.”

I regret to say that no bottles with the labels 22 c, 22 f, 26 d, 35 g could be found when the collection

came to be sorted. They may have been thrown away at once and no record kept of the fact, or, I

tremble to think, have been mixed with an adjacent haul. One can infer from the recorded times of

hauling that in the case of 22 ¢ and 22f they can at most only have been mixed with 22d, 22e, or 229,

if the mistake was made at the time ; and as all are from the surface and at night, no great damage will

have been done. Similarly 26d may have been mixed with 26 e, and 35g with 35 or 357. In these

two latter cases I think that they would eventually show up when the collections have been worked out.

In the meantime I can only plead that it is not easy for two men to keep nets going, sometimes for

twenty-four hours in the day, without making an occasional mistake.

Another error was the labelling of a bottle 31”, no such haul having been made. From a series of

inferences unnecessary to detail, I believe this bottle to contain merely the conspicuous, separately-

preserved organisms of 32n. It has been issued as 32n', and will be treated in the percentages as a

part of 32 n.

21d, 21d'. These were hauled at once, not towed: only part of the catch was preserved.

22 c, 22 f. No bottles to be found with these labels.

283 a. The net-mouth was very slightly open. This seemed to have occurred in the last few fathoms,

owing to the rapid laying up of the wire at the end of the haul. :

25. Stopped in the middle of the haul to put another turn on the drum of the engine-winch : collecting-

tin showed no visible life.

25 d, 25e. There is some doubt whether 25 is not really a part of 25 d.

_ 266. Owing to a collision in the middle of this haul, the net was open for about an extra twenty minutes.

26d. No bottle was to be found with this label.

27 a, 27a’. Owing to a heavy swell, the net failed to close.

27 c. Collecting-tiu contained no visible life.

29 a, 30 a. Mesoplankton trawl.

804, 30c. Heavy rain and thunder overnight.

30. Mesoplankton trawl.

82k. The deepest haul in which anything was noticed to be alive,

85 c, 85d. Nets fouled thermometer-wire : not all the catch was saved.

35 g. No bottle was to be found with this label.

Ge to 361. Open serial tow-nets,

“an

' ote | te ptt ae

P yty ya [

ae. vide bebe Haran

i) a

“@

Fowrrr. TRANS. LINN. SOC. SER. 2, ZOOL. VOL. X. Pl. 1.

® Fathoms.

400

600

el |

“Soe a

CURVES OF TEMPERATURES ACCORDING TO DEPTH.

2400

) Enid

BISC A Y AN Eira NICT ON.

Part II.—THE AMPHIPODA AND CLADOCERA,

WITH NOTES ON A LARVAL THYROSTRACAN,

(Plates 2 & 3.)

By the Rev. T. R. R. Stessine, I.4., FBS, PLS. £Z.S.

AND AN APPENDIX ON THEIR DISTRIBUTION.

By G. Hersert Fowrer, B.A., PhD., PLS. F.ZS.

TABLE OF CONTENTS.

Tinie TOn 2 6p chute Gee 6 Oe EE.5 SERRE ROR ELS Coe DOS OG DSS ORE RAD pice kemre

List of Families, Genera, and Species.

I. AMPHIPODA,

A. GAMMARIDEA.

LysIANASSIDH .......- iCyphocaris, Boctiaeausale alony x. Bocce a4 4. sonst

IRTUSTRED Zs cess ee « 2. Eusirogenes, n.g....... 2. dolichocarpus, n. sp.........

IscHYROCERIDE ...... 3) Jassa, Leach .. asad: 3. pulchella, Leach............

B. Hyprrimera.

DOUNDDEG rare icin So svar: 4. Archeoscina,n.g...,. 4. Bonnieri,n.sp..........-.

3:5 Parascina, 0. farses Set Howlerts ny.Sps, sds daca s 3 Oe

6. Scina, Prestandrea . 6. crassicornis (J. C. Fabricius) .

7. cedicarpus, Stebbing ........

8. marginata, Bovallius........

9. Rattrayi, Stebbing..........

AO Hlepremia (Chere) 52. 2's) 02 2

MMbovealis|(Sars)) 5.4. <6 nev ace

GAN CE OLIN AS. ..</..c/0.0 4 7. Lanceola, Say ........ 12. wstiva, Stebbing .........-

13. pacifica, Stebbing ..........

MVE TET A Secrets ae fe: 8. Vibilia, W.-Edw. ...... 14. armata, Bovallius..........

15. propinqua, Stebbing ........

PHRONIMIDE ........ 9. Phronima, Latreille .... 16. sedentaria (Forskdl)........

PUP ERITDAS fg. 5.5.4 ee10-s 10. Hyperia, Latreille .... 17. luzoni, Stebbing............

11. Hyperioides, Chevreur.. 18. longipes, Chevreuw ........

12. Parathemisto, Bueck.... 19. oblivia (Kréyer) ..........

13. Euthemisto, Bovallius .. 20. compressa (Goés) ..........

eEHOSINYD AQ «ele « te «= 14. Primno, Guérin ...... 21. macropa, Guérin ..........

MEME RED A AS, SEs ete 15. Brachyscelus, Bate .... 22. mediterraneus (Claus) ......

' 23. sp. indeterminate ..........

Il, Crapocera.

WPOLYPHEMIDE ..:..... 1S Evadne oetaeen «e es 1. Nordmanni, Zovén ........

: 2. spinifera, P. FL. Miuller......

UI. Tuyrosrraca,

Pee Cd ROMP ESVPIECIECEG, cs. - 'e oie wicctetenderla eae cleics cas ceo das acsee varied

Pum ee MOC A WA ATS Aa ole ots Sve fe ws) d.Orea WWMM at ed vi Ws os dewele deme edereneme s

LEN a

c~.

| Pn

ue as

14 REY. T. R. R. STEBBING—BISCAYAN PLANKTON :

AMPHIPODA, CLADOCERA, AND A LARVAL THYROSTRACAN

FROM THE Bay oF BISCAY.

The small crustaceans which form the subject of the present report, when entrusted to

my examination by Dr. G, H. Fowler, were contained in 121 tubes, and have proved to

belong to 29 distinguishable, if not in every case determinable, species. Four of these

are Amphipoda Gammaridea, nineteen Amphipoda Hyperiidea, two Cladocera, two

Ostracoda (discussed elsewhere), one the larva of a Cirripede, and one an Isopod, probably

belonging to the genus Hurycope, but too fragmentary for determination. One of the

Gammarids, though ciearly distinct from the rest, was too imperfect for description.

Of the remaining Gammarids one is a very common and one a rare species; the

third is new and supplies the representative of an interesting new genus. Among the

Hyperiids the family Scinide is represented by no less than eight species, two of them

requiring the institution of new genera. In the family of the Hyperiide, Hyperioides

longipes, Chevreux, calls for special remark. It far exceeds in the number of its

occurrences and in number of specimens any other species of Amphipoda in this

collection. Yet this apparently common form was not described, at any rate from the

Atlantic, until the year 1900. To the description by Chevreux speedily followed an

obviously independent account by Dr. Vosseler, and now in quick succession the same

species appears as a predominant constituent of Dr. Fowler’s collections.

The present opportunity has been taken for making more generally known the characters

of the juvenile Primno among the Hyperiids, and the external appearance of the Cypris-

larva of Lepas pectinata among the Thyrostraca.

AMPHIPODA GAMMARIDEA.

Fam. LYSIANASSID4.

CypHocaris, Boeck, 1871.

1871. Cyphocaris, Boeck, Vid.-Selsk. Forhandl. (Christiania) for 1870, p. 103 (23).

1888. Cyphocaris, Stebbing, ‘Challenger’ Amphipoda, Reports, vol. xxix. pp. 398, 656.

1900. Cyphocaris, Chevreux, Amphipodes de |’ Hirondelle, p. 165.

It does not appear that Liitken took any part in the definition of this genus, although,

according to Boeck, he chose its name. It was therefore, as I now think, an error of

judgment on my part to name Liitken and Boeck as joint founders of the genus.

1. CYPHOCARIS ANONYX, Boeck.

1871. Cyphocaris anonyx, Boeck, Vid.-Selsk. Forhandl. (Christiania) for 1870, p. 104 (24).

1872. Cyphocaris anonyx, Boeck, Skand. og Arkt. Amphipoder, vol. i. p. 141, pl. 6. fig. 1.

1888. Cyphocaris micronyx, Stebbing, ‘Challenger’ Amphipoda, Reports, vol. xxix. p. 656, pl. 16.

1890. Cyphocaris micronyx, Chevreux, Amphipodes de |’ Hirondelle, p. 165.

1903. Cyphocaris anonyx, A.O. Walker, Ann. & Mag. Nat. Hist. ser. 7, vol. xii. p. 232, pl. 18. fig. 14.

The points in which the descriptions of C. anonyx and C. micronyx differ are fully

sufficient for specific distinction, but they seem little worth insisting on until fresh

specimens have been obtained corroborating the earliest description. C. anonyx was found

THE AMPHIPODA. 15

in Greenland waters, and while C. micronyx was known from no nearer habitat than

Tristan da Cunha, the distinctness of the two species had a sort of geographical support.

This, however, is greatly weakened by the finding of C. micronyx in the Bay of Biscay,

and the earlier report of its capture by the Prince of Monaco’s yacht |'Hirondelle at

AT? 38' 13" N., 22° 13! 40" W.

Occurrences: 21 %. 300 to 400 fathoms. 1 specimen. f

32 1. 300 to 400 fathoms. 1 specimen.

Fam. EusiIRID &.

EUSIROGENES, n. g

In general agreement with Husirus, but with the head arching over the base of the

first antennze, distal margin of the upper lip straight, third joint of mandibular palp shorter

than second, inner plates of the maxillipeds completely separate, second gnathopods much

smaller than first, the fifth joint in both pairs proximally elongate with the cup-forming

process little developed.

2, EUSIROGENES DOLICHOCARPUS, n. sp. (Plate 2 A.)

Though the solitary specimen on which the new genus and species are founded was

both defective and damaged, a sufficient number of important features were in satis-

factory condition. ‘The flagellum of the second antenne, the third and fourth perzeopods

and the three terminal joints of the first, second, and fifth pairs, the third’ uropods, and

the telson were entirely missing. The thin papyraceous integument was crumpled,

making it difficult to determine the exact relative positions of the side-plates. Nor

could their several shapes and sizes be determined prior to dissection. The back of the

perzeon appeared to be rounded, not carinate, with little difference in length between the

segments. Of the pleon-segments the first three were much longer, the second and third

much deeper, than those of the perzeon. The postero-lateral angles of the third segment

are smoothly rounded, not serrate; the fourth is longer than the fifth and sixth

. combined, and has a saddle-like dorsal depression. On this and each of the three

preceding segments there seemed to be one or two postero-dorsal denticles, but these were

minute and it was not possible to determine whether they terminated carinze or mere

accidental folds of the pellucid skin.

The mouth-organs were in good order, but collectively were most likely out of position,

since the whole mass pointed downwards at right angles to the head, with the long palps

of the mandibles projecting fantastically between the gnathopods. The head itself was

opaque, longer than wide, without rostrum, though the curved sides of its triangular form

ended in a minute point. Beyond the base of the first antenn:e it was hollowed into an

arch. It must, however, be borne in mind that the oral parts, though firmly knit

together among themselves, showed signs of a forcible dislocation by which the cephalic

framework may have had its appearance seriously modified.

Of eyes no trace was observable.

First antenne.—First joint rather long, with strong distal tooth on the inner side,

Na xg

eo,

16 REV. T. R. R. STEBBING—BISCAYAN PLANKTON :

second joint a little shorter, third short; flagellum of 31-84 joints, about thrice as long

as peduncle, with subapical setules, which on the joints of the proximal half form short

fringes. Accessory flagellum consisting of a single spine-like joint, about three-fourths

as long as the second of the peduncle.

Second antenne.—The gland-cone is very prominent on a very short joint. The two

following joints are slender, the first half as long as the second, the latter nearly as long

as the first of the first antenne.

Upper lip.—Distal margin straight and smooth in centre, at each end slightly rounded

and hirsute.

Mandibles.—Cutting-edge and secondary plate not very broad, the teeth small ; spine-

row of four spines; molar moderately powerful, a denticulate oval not occupying the

whole of the crown; palp elongate, set well forward; first joint short, second consider-

ably longer than the third.

First maxille.—Inner plate seemingly very slight; outer plate with ten spines, some

of which have a lateral denticle ; first joint of palp scarcely half as long as second, the

latter apically fringed with sete.

Second maxille—Inner plate short, the rounded apex fringed with a few short

spinules ; the outer plate little more than half as broad, with several long apical spines.

Mazxillipeds.—Inner plates not partially coalesced as in Eusirus, their apical spines

slender; outer plates little broader, their spines slender ; second, third, and fourth joints

of palp elongate, subequal in length,

First gnathopods.—Second joint long, distally narrowed, channelled in front, third and

fourth joints short, fifth nearly as long as second, its long narrow stem widening to the

commencement of the shallow cup in which the trapezoidal hand reposes. The powerful

hand, or sixth joint, has four unequal margins, the front one, to the base of which the

fifth joint is attached, being the shortest. The longest is the palmar margin, a horny-

looking strip fringed with little spinules; the finger is attached at its base and with

curved apex overlaps its distal end, on which are planted two spines, one long, the

other short. The other two margins, which meet in a rounded obtuse angle, perhaps

together represent the hind margin of this muscular joint.

Second gnathopods.—These are distinguished from the first by having several long

setee on the hind margin of the second and fifth joints, by having the stem of the latter

considerably wider, the hand and finger very much smaller, the palm more convex and

not overlapped by the finger. Also, the stem of the fifth joint, stead of being not much

longer than the part which forms the cup, is here nearly two anda half times as long.

In both pairs the finger is shaped to correspond with the palmar margin.

First and second pereopods.—Extremely slender ; second joint elongate, third short,

fourth (in second pair) long, but much shorter than the second.

Third pereopods.—The side-plates of this pair are very unequally bilobed.

Fifth pereopods.—The second joint is little longer than broad, with a slight narrowing

distally : the fourth joint is a little longer, slender, slightly curved.

Pleopods.—Peduncle carrying two small coupling-hooks ; the first joint of inner ramus

armed with five cleft spines, this ramus (in one pair) having fourteen joints, and the

outer fifteen,

THE AMPHIPODA. 17)

First uropods considerably longer than second; peduncle longer than the rami, which,

however, are long and slender, with small spines along both margins and some micro-

scopic pectination, the outer ramus the shorter.

In the second pair the inner ramus is subequal in length to that of the first pair,

longer than its peduncle, and much longer than the outer ramus.

Length, from apex of head to end of fifth pleon-segment, 7°5 mm., so that the length

to the end of the uropods, but exclusive of the antenne, may be estimated at over 10 mm.

As the net (the mesoplankton trawl) was hauled fast, with a view of capturing large

organisms, it is not surprising that the specimen was damaged.

While the generic name refers to the probable evolution of this genus from Eusirus,

the specific name, meaning “long-wristed,” alludes to the character of the fifth joint in

both pairs of gnathopods, differentiating this form from all previously known Eusiride.

Occurrence: 30e, mesoplankton trawl. 2000 to 1000 fathoms. 1 specimen.

Fam. ISCHYROCERIDA.

Jassa, Leach.

1814. Jassa, Leach, Edinburgh Encyclopedia, vol. vii. p. 433 (Art. Crustaceology, Appendix).

1899. Jassa, Stebbing, Ann. & Mag. Nat. Hist. ser. 7, vol. ii. p. 237.

3. JASSA PULCHELLA, Leach.

1814. Jassa pulchella, Leach, Edinburgh Encyclopedia, vol. vii. p. 433.

1894. Podocerus falcatus, Sars, Crustacea of Norway, vol. i. it 27, p. 594, pl. 212.

1899. Jassa pulchella, Stebbing, Aun. & Mag. Nat. Hist. ser. 7, vol. 1. p. 239.

A discussion of the synonymy of this abundant and well-known species will be

found in the ‘Annals and Magazine of Natural History’ above cited, and an excellent

description in Sars’s great work on the Crustacea of Norway. The celebrated Norwegian

uthor speaks of the “last pair of uropoda with the inner ramus distinctly hooked.”

.ecording to my observation it is not the inner but the outer ramus that is hooked.

Occurrences: 24 f. 0 fathoms. 8 small specimens.

24 7.0 fathoms. 2 specimens and a fragment.

AMPHIPODA HYPERIIDEA.

; The first three families of this division may conveniently be distinguished by the

lowing synoptic table :—

-§ Mandibles with molar ; fingers of fifth pereopodsobtuse . . . . . . . . 3. Vipiiupse,

i: “UMandibles without molar; fingers of fifth pereopods acute. 2.

Fingers of third, fourth, and fifth perwopods not retractile. . . . . . . . 1. Scinipe.

Fingers of third, fourth, and fifth perwopods TELMACEIIGM CN a.) > <3) 08 al, eee) UANCEOLIDR.

A valuable table for the families of the Hyperiidea at large is supplied by Boyallius in

the first part of his monograph on the group, published in 1837.

_ SECOND SERIES.—ZOOLOGY, VOL. xX. 4

18 REV. T. R. R. STEBBING—BISCAYAN PLANKTON :

Fam. ScINID4.

1849. Corophide (part.), Dana, Amer. Journ. Sci. ser. 2, vol. viii. p. 140.

1853. Corophide (subfam. Clydonine), Dana, U.S. Expl. Exp. vol. xiii. pp. 829, 831.

1862. Corophiide (subfam. Corophiides), Bate, Brit. Mus. Catal. Amph. pp. 233, 273.

1862. Hyperide, Bate, Brit. Mus. Catal. Amph. p. 308.

1877. Corophiide (subfam. Clydonine), Streets, Contributions Nat. Hist. Hawaiian and Fanning

Islands and Lower California, p. 124.

1882. Clydoniide, Sars, Christiania Vidensk. Forhandlinger, No. 18, p. 20.

1887. Tyronide, Bovallius, Bihang t. K. Svensk. Vet.-Ak. Handl. Bd. xi. No. 16, p.3; K. Svensk.

Vet.-Ak. Handlingar, Bd. xxi. No. 5, p. 3.

1888. Scinide, Stebbing, ‘ Challenger’ Amphipoda, Reports, vol. xxix. p. 1270.

1889. Fortunate, Chun, Math. u. Naturw. Mittheilungen Ak. Berlin, Bd. xlv. p. 535 (345).

1889. Scinide, Chun, Zool. Anzeiger, xii. Jahrg. pp. 286, 308.

1890. Scinide, Sars, Crustacea of Norway, vol. i. p. 18.

1895. Scinide, Stebbing, Trans. Zool. Soc. London, vol. xiii. pt. 10, p. 349.

1896. Scinide, Garbowski, Denkschr. k. Akad. Wiss. Bd. Ixiii. (Ber. Comm. Erforsch. éstl. Mittel-

meeres, fiinfte Reihe, p. 39).

1900. Scinide, Chevreux, Amphipodes de l’Hirondelle, p. 121.

1901. Scinide, Vosseler, Amphipoden der Plankton-Exp. pt. i. p. 100.

Head usually broader than long, with eyes, when present, small and distant. Pleon

narrower than perzeon, its fifth and sixth segments coalesced, and telson small. First

antennz large, tapering, with little flexibility, attached at the front corners of. the

head. Second antennee attached below and behind the first, variable with age and sex.

Mandibles without molar. First and second maxillee well developed. First and second

enathopods simple, slender. Of perzeopods usually third pair longest and fifth shortest ;

fingers acute, not retractile. Inner branch of uropods usually coalesced with the

peduncle.

The definition of the family is here modified to admit the new genus Archeoscina,

which has a mandibular palp, and the new genus Parascina, in which the maxillze are

distinctive and the uropods show a clear demarcation between inner ramus and peduncle.

Future discoveries will probably justify the withdrawal of Archeoscina from its present

position to form the type of a new family Archeoscinide. For the present the genera

of Scinidee may be distinguished as follows :—

Mandibles*withipalp ©. 2 .. 25 «1s we ee le eed

*CMandibles without palp. 2.

Palp of first maxilla extremely broad, inner plate cf seccnd maxilla broader than

outer? . ee Fees fe Ae Re Ao)

Palp of first maxilla not very broad, inner plate of second maxilla narrower than

outer. 3.

Dorsal carina produced into teeth . : - . . . . 8&8. Acanthogamas

at: Segments of trunk without dorsal teeth. . . . . . =. 2.4. . ».. =. . 4 Scing,

Acanthoscina was instituted by Vosseler in 1901 for a species, A. serrata, which he

supposed to be new. Dr. Vosseler happened at the time to be unacquainted with

Scina acanthodes, Stebbing, published in the Trans. Zool. Soc. London, in 1895. This

he has since recognized as identical with his own A. serrata, and therefore as the type

of his new genus.

THE AMPHIPODA. 19

ARCHOSCINA, 0. &

In general habit and in the appendages of person and pleon like Scina.

Mandibles with a three-jointed palp, in which the third joint is much the longest. All

three pairs of uropods with the outer branch well developed, longer than the peduncle.

In regard to the above definition, it may be observed that the first antennze have the

form found in the young of species evidently belonging to Seina. It is also probable

that the long inner branch of each uropod is jointed to the peduncle, but this feature is

not exhibited with sufficient clearness in the only available specimen to be relied on as

a generic character. Should it be in future more positively ascertained, it will strengthen

the inference, drawn from the presence of a mandibular palp, that Archeoscina is really an

archaic Scina, retaining properties which other members of the family have relinquished.

Changes in the mode of defining the new genus will no doubt be required if further

examples of the species on which it is founded show a more advanced development,

but the mandibles will still distinguish it from all hitherto known Scinide *.

4, ARCHMOSCINA BONNIERI, n. sp. (Plate 3.)

The single specimen from its minuteness and the shape of its first antenne ran ‘a risk

of being laid aside as a young one of some species of Seina. The material at hand for

comparison was not sufficient to encourage a hope that the question of such relationship

could be settled. On the other hand, from two specimens of about the same size,

undoubtedly juvenile species of Sina, the present form was distinguished by having the

back imbricated instead of smooth, by the numerous sensory filaments on the first

_antennze, and the needle-like spine on the second. Dissection showed a still more

notable difference in regard to the mandibles.

' Whether the first and second segments of the person were distinct or partially

coalesced, and whether any eyes were present or not, could not be made out. The

postero-lateral angles of the first three pleon-segments are rounded.

The first antenne are planted wide apart. Two short, apparently separate, peduncular

joints are followed by a thick slowly tapering joint, fringed on the inner margin with

eight or more pairs of sensory filaments. To this succeed two small narrow joints

fo llowed by a longer transparent joint with two spinules projecting from its blunt apex.

‘The second antenns appear to have four peduncular joints, none of them very long,

wed by one or two small flagellar joints and at the end the needle-like spine, leita

all the joints of the appendage together and extending beyond the first antennz.

andibles.—The exact shape and armature could not be satisfactorily made out, but

ich the palp was uninjured, with second joint longer than the first, and the slightly

; ed tapering third longer than both the others combined. With the other mouth-

_ organs the dissection was not sufficiently successful to admit of description.

The gnathopods are of the character familiar in the genus Scina, the third and fourth

* “On Vagaries of the Mandibular Palp in the Hyperiidw.” See pp. 34, 35.

SECOND SERIES.—ZOOLOGY, VOL. X. S)

First antenne short and thick; second slender, straight, ending in an elongate spine.,

20 REY. T. R. R. STEBBING-—BISCA YAN PLANKTON:

length, the sixth (decidedly in the second pair and less certainly in the first) being

produced into a point over the base of the slender finger.

The first and second perzeopods have the fourth and fifth joints broad, with very

convex front margin, the fourth joint about as broad as long. The fingers in all

the perzeopods are slender, strongly curved at the tips.

The third perzeopods are without any conspicuous armature, and have no teeth or

serration on either margin of the second joint, the fifth joint is longer than the fourth >»

and the sixth than the fifth.

The fourth perzeopods are shorter than the third, the difference chiefly depending on

the sixth joint, which is subequal to the fifth.

The fifth pereeopods are very slightly if at all shorter than the fourth on the whole, but

have a decidedly shorter fourth joint.

The pleopods have a robust peduncle with a coupling-hook ; the rami six-jointed, with

a cleft spine on the first joint of the inner ramus.

The first uropods are the longest, with the outer ramus rather less, and the inner

considerably more, than twice the length of the peduncle, both rami serrate on each

margin. The second uropods are the shortest, with the peduncle barely half the length

of the outer ramus, which carries some small spinules on the inner margin and is more

than two-thirds the length of the inner ramus. The third uropods have a peduncle

nearly as long as that of the first pair, but the inner ramus only as long as the outer of

that pair; the outer ramus is four-fifths the length of the inner. ‘The inner rami, as

already mentioned in relation to the generic characters, show some indication of being

jointed to the peduncle.

Telson apparently oval, very small; so pellucid that its boundaries could not be

exactly ascertained.

Length.—From the apex of the first antennze to the end of the third pleon-segment

the specimen measured about one-twentieth of an inch, or 1:25 mm. With the pleon

unfolded this would give perhaps a total length to end of uropods of 1:75 mm.

The species is named in compliment to M. Jules Bonnier, whose excellent account of

numerous sessile-eyed Crustaceans taken by the ‘Caudan’ in the Bay of Biscay is well

known.

Occurrence: 35 k. 400 to 300 fathoms. 1 specimen.

PARASCINA, 0. g.

Near to Scina, but differing in the mouth-organs and uropods. First maxillze with

outer plate very broad, its distal border undivided and surmounted with spines and

spinules ; the palp one-jointed, very broad, distally unarmed. Second maxille with inner

plate rotundo-quadrate, hirsute, much broader than the somewhat conical and more

strongly armed outer plate. Maxillipeds having a pair of broad inner plates, the outer

plates almost semicircular, the apices narrowed but not lanceolate. Gnathopods and

pereopods with very slender fingers. Third pereeopods with second joint not serrate.

The uropods all with outer branch well developed, and the inner jointed to the

peduncle.

THE AMPHIPODA. 21

5. Parascina FowLeERI, n.sp. (Plate 2B.)

Front of head straight, inclining to concave, back seemingly rounded, side-plates of

pereon small, not angular; first three segments of pleon with postero-lateral angles

rounded, fifth and sixth segments coalesced. Eyes protuberant.

First antennz considerably shorter than the perzeon, the peduncle short, two-jointed ;

first joint of flagellum as in Scina long, stout, tapering, bordered with sensory filaments,

moderately numerous and slender. To the apex of the long joint succeed two small

distinct joints, followed by a short spine-like piece resolvable into two slender joints and

a spine.

Second antenne.—These are of the rudimentary character usual in the female Scinide.

The first joint is broader than long; the second longer than the first, tapering, rather

suggestive of two joints coalesced; the third minute, tipped with a minute setule.

The upper lip was not very exactly determined. It has apparently a small very

unsymmetrically placed emargination of the distal border.

The mandibles are long and narrow, widest at the point at which the margin becomes

free and slopes to the cutting-edge. This is furnished with a rather large tooth above

and a smaller one below. On one mandible there is perhaps a small inner plate, but

certainly none on the other, on which, however, the lower tooth seems to be subdivided.

The surface of the mandibles is hirsute near the cutting-edge and also in the place of

the spine-row. The molar is unrepresented.

The lower lip has two rounded principal lobes, which are feebly hirsute. The mandi-

bular lobes are rather broadly rounded.

First maxille.—The inner plate has an even width, with a slight curve, the dista’ part

and broadly rounded apex being strongly hirsute. The outer plate continues the

considerable breadth of its base, and carries a group of spinules on the surface

_ proximally, while the free border is fringed round with spinules, to which are added five

‘strong spines on the broad flattened distal margin, and some slighter ones on the outer.

The palp at the base is not quite so wide as the outer plate, but presently in super-

position outflanks it on both edges and reaches beyond its distal spines, being itself

armed only with four to six spinules spaced along its outer margin.

1 _ Second maxille—tThe inner plate is very broad, squarely truncate at the distal

Margin, which with the straight inner edge is strongly hirsute; the slightly convex outer

| 4 argin is smooth, except distally, where two larger spines are set among some that are

mailer. ‘The surface carries spinules and spines, of which one near the inner distal angle

6 is conspicuous. The outer plate is much narrower, with nearly straight inner and

St, convex outer margin meeting at the apex, both fringed with slender spines, the outer

eet

margin carrying distally four of stronger build.

The maxillipeds have two broad inner plates, or possibly a single plate divided

into two lobes, both distally hirsute, the distal corner of each (as seen separate and

flattened) forming a little sharp point. The outer plates are much larger, smoothly

_ Tounded externally till near the apex, where three spines are spaced. The inner

_ margins are adjacent, except at the apex, and are fringed each with eight or nine slight

pines,

22 REV. T. R. R. STEBBING—BISCAYAN PLANKTON:

The first gnathopods have a group of spines at the truncate end of the short fourth

joint, the hind margin of the fifth carrying three spines on its proximal half and a

group at the apex. The narrower, somewhat tapering, sixth joint has a few spmes on

each margin, and is produced into a spine-like tooth on each side of the slender finger,

which is microscopically hirsute near the middle and has a tiny indent near the apex.

The second gnathopods nearly agree with the first, but are rather longer and more

slender, the sixth joint being as long as the fifth, without instead of with the partial help

of the distal processes. The branchial vesicle is not much shorter than the second joint.

The first and second perzeopods have the fourth joint short but rather broad ; the. fifth

glandular, subequal in length to the narrow tapering sixth, but much broader, both

being armed with very slight spinules. The finger is short, slender, little curved.

The third, fourth, and fifth perzeopods differ but little one from the other. In all the

fourth joint is more than half as long as the fifth, the fifth is subequal in length to the

narrowly tapering sixth, and is not much shorter than the second. The finger in all

is slender, little curved, and very short. The fifth pair is not quite so long as the two

preceding pairs.

The pleopods are of the usual character, carrying a cleft spine on the first joint of the

inner ramus, this branch being seven-jointed, while the outer branch has eight joints.

The first uropods have the outer branch more than two-thirds the length of the inner

and a very little shorter than the peduncle. The peduncle is serrate on the outer

margin, the inner branch pretty strongly and the outer feebly on both edges. The

second have the peduncle and inner ramus each a little shorter than in the first pair,

but their breadth is rather greater, the armature similar, and the (broken) inner ramus

is indicative of a like proportional length. ‘The third pair are the shortest ; they have

a broad peduncle with smooth margins. The strongly tapering inner ramus is a little

longer than the peduncle, faintly serrate on the outer margin; the outer ramus, similar

in shape, is less than two-thirds the length of the inner, with its inner margin feebly

serrate.

The small oval telson, by its extreme transparency, is obscure in outline.

Length, from apex of first antennze to extremity of uropods, 8 mm., of which the first

antennz measure about 1°75 mm.

The species is named in well-deserved compliment to Dr. G. Herbert Fowler.

Occurrences: 26d. 2000 to 1500 fathoms. 1 mutilated specimen, 8°75 mm. long.

27 a. 1250 to 0 fathoms. 1 specimen.

Sctna, Prestandrea, 1833.

Down to the present century this genus by itself constituted the family, and the

synonymy can easily be discovered from the references already given in connection with

the family designation.

With regard to the subjoined tabular view of existing species, some remarks are

requisite. As already noticed, the species Scina acanthodes has been transferred to a

new genus Acanthoscina, of which the mouth-organs are not yet known with any great

i ee ee

THE AMPHIPODA. 23

exactness. The species Scéna Chuni, Garbowski, figured and described in that author’s

very important treatise on the Scinidee, cannot be distinguished from the earlier Scina

stenopus published in the Trans. Zool. Soc. London, 1895. S. dongipes (Dana) remains for

the present obscure. As observed by Dr. Garbowski, no weight can be attached to such a

character as the angular prominence which Dana depicts and speaks of as representing the

medio-frontal margin of the head. Dana regards the fifth and sixth segments of the pleon

as separate. In these pellucid animals the ventral dividing-line may easily be mistaken

for a dorsal division. Scina spinosa, Vosseler, 1901, founded on a female specimen

35 mm. long, “perhaps not quite full-grown,’ should not, I think, be separated from

SS. uncipes, which I founded in 1895 on a male specimen 7°5 mm. long, this being, to

judge by the second antenne, almost completely mature. Scina Lamperti, Vosseler,

1901, which, like S. wdicarpus, has the second joint of the third perzeopods longer than

all the rest of the limb, is distinguished by an approach to a subchelate ending of the

first and second perzeopods. One of these is represented by Vosseler (pl. 9. figs. 3, 3),

but referred to in the ‘ Tafel-Erklarung’ as “ Zweites Brustbein,” which would indicate

the second gnathopod. Other specific names not included in the tabular view are

mentioned in the following notes on accepted species.

First antenne considerably longer than body. 2.

First antennee little or not at all longer than body. 4.

Prp. 3, second joint longer than following joints combined . . 1. S. edicarpus, Stebbing.

Prp. 3, second joint not longer than following joints combined. 3.

Peltesivantenne sto 5. ee we ee ee ww eS crassicornis (Fabricius).

(First antenne slender . . . : . . 8. 8S. stenopus, Stebbing.

First and second gnathopods, apex of sixth jou BP cided! 5.

First and second gnathopods, apex of sixth joint not produced. 6.

Prp. 5 more than half the length of prp.4 . . . . . . . 4. S. marginata (Bovallius).

“€ Prp. 5 much less than half the length of prp.4. . . . . . 5. S. incerta, Chevreux.

Prp. 3, second joint with front margin dentate only at apex. 7.

Prp. 3, second joint with front margin dentate not only at apex. 10.

Prp. 3, second joint with apical tooth bifid . . . . . . . 6. S. pacifica (Bovallius).

Prp. 3, second joint with apical tooth simple. 8.

Prp. 4, fifth joint shorter than fourth or sixth . . . . . . 7. S. similis, Stebbing.

Prp. 4, fifth joint longer than fourth or sixth. 9.

Melson triangular “3. ; . ww ee we te es wl el te 8. S. Tullbergit (Bovallius).

whelsomiruncate’ 97.9: . . 2 uw & « «9. 8. concors, Stebbing.

Prp. 3, second joint with few iat on eal margin. . . . 10. S. Rattrayi, Stebbing.

Prp. 3, second joint with many teeth on front margin. 11.

Prp. 3, second joint longer than following joints combined . . 11. S. Lamperti, Vosseler

Prp. 3, second joint shorter than following joints combined. 12.

Prp. 3 not longer than prp. 4. 13.

Prp. 3 longer than prp. 4. 14.

Prp. 3 with sixth and seventh joints short . . . . . . . 12.

Prp. 3 with sixth and seventh joints long. . . . . . . . 13.

nena se... eee) «1K,

PRR NOUGECM UL fs. we ee Dal. 2. 1K

Clausii (Bovallius).

lepisma (Chun).

borealis (Sars).

uncipes, Stebbing,

13.

wae JA,

24 REV. T. R. R. STEBBING—BISCAYAN PLANKTON:

6. Scrna craAsstcorNis (J. C. Fabricius).

1775. Astacus crassicornis, Fabricius, Systema Entomologie, p. 415.

1793. Astacus crassicornis, Fabricius, Entomologia Systematica, p. 481.

1793. Cancer (Gammarellus) crassicornis, Herbst, Krabben und Krebse, Bd. ii. p. 134.

1830. Hyperia cornigera, M.-Edwards, Ann. Sci. Nat. vol. xx. p. 387.

1840. Tyro cornigera, M.-Edwards, Hist. Nat. Crust. vol. i. p. 80.

1853. Clydonia gracilis, Dana, U.S. Expl. Exp. vol. xiii. p. 834, pl. 55. fig. 6 a, b.

1885. Tyro atlantica, Bovallius, Bihang t. K. Sv. Vet.-Akad. Handl. Bd. x. No. 14, p. 14.

1885. Tyro Sarsii, Bovallius, Bihang t. K. Sv. Vet.-Akad. Handl. Bd. x. No. 14, p. 15.

1887. Tyro Sarsi, Bovallius, K. Sy. Vet.-Akad. Handl. Bd. xxi. No. 5, p. 9, pl. 1. figs. 1-17,

pl. 2. figs. 1-10.

1887. Tyro atlantica, Bovallius, K, Sv. Vet.-Akad. Hand]. Bd. xxi. No. 5, p. 18, pl. 2. figs. 11-18.

1888. Scina cornigera, Stebbing, ‘Challenger’ Amphipoda, Reports, vol. xxix. p. 1273, pl. 146.

1895. Scina cornigera, Stebbing, Trans. Zool. Soc. London, vol. xiii. pt. 10, p. 851.

1896. Scina Edwardsi, Garbowski, Denkschr. k, Akad. Wien, Bd. Ixiii. p. 103 (67), pl. 1. fig. 2,

pl. 3. figs. 19-33, pls. 4-7, pl. 8. figs. 97-109.

1900. Scina cornigera, Chevreux, Amphipodes de |’ Hirondelle, p. 121.

1901. Scina Edwardsi, Vosseler, Die Amphipoden der Plankton-Exp. p. 103.

Additional references might be given, but the above will suffice to explain the

synonymy of this species. When describing it as Scina cornigera in 1888, I considered

that Dana’s Clydonia gracilis could not be distinguished from it, and with this opinion

Dr. Vosseler, the latest writer on the group, agrees. In 1895 I called attention to the

probable identity of Zyro Sarsii, Bovallius, and this conclusion, which is accepted by

my friend M. Ed. Chevreux, was independently arrived at by Dr. Garbowski in 1896.

The last-named author, in his elaborate treatise on the Scinidze, also forcibly argues

that S. atlantica (Bovallius) is a further synonym. But he thinks it advantageous to

discard both the names (atlantica and Sarsii) given by Bovallius, and to establish in

place of them “ Scina Hdwardsi, n. sp.” ‘This designation is accepted by Dr. Vosseler,

who to “ Scitna Hdwardsi, Garbowski,” allots no less than five earlier synonyms, since,

besides those already mentioned, beginning with the cornigera of Milne-Edwards, he

includes the dongipes of Dana. The inclusion of this last must be regarded as extremely

hazardous, but all the rest appear to take legitimate precedence of the name Hdwardsz.

There is, however, a name earlier than any of them, which ought not to be neglected.

This is the erassicornis of J. C. Fabricius, a name probably adopted from the manuscript

title of Cancer crassicornis, painted by Sydney Parkinson in 1768, of which the

drawing, still unpublished, is preserved in the Natural History Museum. Formerly I

thought that the description by Fabricius was not sufficiently definite to justify the

maintenance of his specific designation, of which the priority was otherwise beyond

dispute. Now, however, it appears from the synoptic table of all the known species

that there is really only one which adequately satisfies the conditions of the earliest

description. There are only three out of the fourteen which have the anterior antennz

longer than the body. But of these Seina stenopus has the first antennze not “ erassi-

uscule,’ but remarkably slender, and Scina edicarpus is an animal so small that the

carination of the back if existent could scarcely have been noticed in the eighteenth

prEN

THE AMPHIPODA, 25

century. Moreover, in both these species there is much less disparity of length between

the third and fourth perzopods than that which is indicated by Fabricius. The still

obscure and unplaced Scina longipes (Dana), with its acutely-produced head-front, does

not come into competition with any known form.

A male specimen from Station 31 measured 22 mm. from apex of first antenna to

extremity of third uropod; in another the length from front of head to end of uropod

was 13 mm., the first antennze being 8°75 mm. long and the first uropods 3°75 mm.

Occurrences: 33a. 0 fathoms. 1 specimen, ¢.

34a. 25 to 0 fathoms. 2 specimens.

30 7. 50 to 0 fathoms. 1 specimen, ¢.

31 6. 50 to 0 fathoms. 9 specimens, of which 6 ¢.

34¢. 75 to 0 fathoms. 1 specimen.

35x. 100 to 0 fathoms. 1 specimen.

7. Scina @picarPvs, Stebbing.

1895. Scina edicarpus, Stebbing, Trans. Zool. Soc. London, vol. xiii. pt. 10, p. 356, pl. 528,

This is an exceedingly transparent little species, and I have not been able to determine

whether the thin pellucid integument shows any trace of a medio-dorsal carina. The

specific name has not proved very appropriate, since the “swollen carpus” is still more

conspicuous in the fifth perzeopods of 8. Lamperti, Vosseler, and elsewhere.

Occurrences: 32d. 100 to 0 fathoms. 1 specimen, ¢ juv.

36f. 150 to 0 fathoms. 2 specimens,1 2,1 ¢ not fully mature.

8. Scrna MARGINATA (Bovallius).

1885. Tyro marginata, Bovallius, Bihang t. K. Svenska Vet.-Akad. Handl. Bd. x. No. 14, p. 15.

1887. Tyro marginata, Bovallius, K. Sv. Vet.-Akad. Handl. Bd. xxi. No. 5, p. 21, pl. 3. figs. 18-33.

1888. Scina marginata, Stebbing, ‘ Challenger’ Amphipoda, Reports, vol. xxix. p. 1272.

1889. Fortunata lepisma, ¢, Chun, Math. u. Naturw. Mittheilungen Ak. Berlin, Bd. xlyv. p. 533

(343), pl. 3. fig. 8.

1889. Scina lepisma, Chun, Zoologischer Anzeiger, Jahrg. xii. No. 308, p. 289.

1895. Scina marginata, Stebbing, Trans. Zool. Soc. London, vol. xiii. pt. 10, p. 351.

1896. Scina marginata, Garbowski, Denkschr. k. Akad. Wien, Bd. lxiii. p. 100 (64), pl. 2, pl. 3.

figs. 17, 18.

1900. Scina marginata, Chevreux, Amphipodes de l’Hirondelle, p. 122, pl. 14. fig. 8, pl. 15. fig. 1.

1901. Scina marginata, Vosseler, Amphipoden der Plankton-Exp. p. 110.

Dr. Garbowski makes Scina ensicorne, Prestandrea, 1833, a synonym of this species,

without, however, restoring Prestandrea’s specific name. But the identification cannot

easily be maintained, for whereas Bovallius says of his species, ‘“ the body is not carinate,”

Prestandrea says just as expressly that the body of S. ensicorne is dorsally carinate. He

further states that the body is 5 lines long and the superior antennz 34 lines.

This amounts to a total length of more than 17 mm., while of S. marginata the

total length is given by Bovallius at 6 mm., and Vosseler expresses surprise at finding

specimens 8 mm. long. By the sharply-produced anterior apices of the gnathopods

26 REY. T. R. R. STEBBING—BISCAYAN PLANKTON:

S. marginata is distinguished from all other definitely known species of the genus except

Scina incerta, Chevreux, and from the latter, in Chevreux’s words, ‘sous tous les autres

rapports, elle différe absolument.”? Thus in the third pereopods there are teeth along

the front margin which are wanting in S. incerta; the sixth joint is much shorter than

the fourth instead of being equal to it in length; the whole limb is considerably instead

of only a little longer than that of the fourth pereeopod ; and the fifth pair are more than

half the length of the fourth, while in S. ¢ncerta they are only a third of the length of

the preceding pair.

Length of single specimen 4°5 mm., the first antennz representing 1:25 mm. of this

measurement.

Occurrence: 35 p. 250 to 150 fathoms. 1 specimen.

9. Scrna Rarrrayi, Stebbing.

1895. Scina rattrayi, Stebbing, Trans Zool. Soc. London, vol. xii. pt. 10, p. 358, pl, 53 a.

1900. Scina Rattrayi, Chevreux, Amphipodes de l’Hirondelle, p. 123, pl. 15. fig. 2.

1901. Scina Bovallii, Vosseler (not Chun), Amphipoden der Plankton-Exp. p. 105, pl. 9. figs. 8-17.

1901. Scina Rattrayi, Lo Bianco, Mittheil. Stat. Neapel, vol. xv. pp. 422, 446.

1903. Scina Rattrayi, A. O. Walker, Ann, & Mag. Nat. Hist. ser. 7, vol. xii. pp. 223, 231.

This species was originally described from a single female specimen. Chevreux had

at his disposal two male adult specimens, one young male and one female. He

deseribes the second antennz as observed in the adult males. Vosseler describes an

adult male and a young female under the designation “ Scina Bovallii, Chun.” In 1889

Chun applied the name Fortunata lepisma to two specimens, which later in the same

year he divorced under the separate names of Scina lepisma 2 and Scina Bovallit 2.

But if the ruling be accepted that the female which Chun described and figured belongs

to the earlier Scina marginata (Bovallius), it follows that the name Scina lepisma will

cling to the male form. ;

There cannot be any reasonable doubt that Vosseler’s Scina Bovallii is identical with

my Scina Rattray, which had, unluckily, not come under Dr. Vosseler’s notice when he

published his valuable treatise on the Hyperiidea of the Plankton Expedition. He

recognizes, however, that the identification which he actually adopts without hesitation

presupposes several defects in Chun’s figure and description of the species. In regard

to the third perzeopods, Chun states that the fourth joint is shorter than the fifth, also

that it is shorter than the sixth, and that the finger is long. But in this limb of Sena

Rattrayi the finger is minute, and the fourth joint is much longer than all the

following joints combined. Chun says that the fourth perzeopods are somewhat longer

than the third, and Vosseler says the same of the species which he describes; but his

figures of these limbs do not support this statement, nor does it apply to Chevreux’s

figures of Scina Rattrayi, nor to the specimens which I have examined. Chun

institutes a comparison between his species and Scina borealis (Sars) and Scina Clausi

(Bovallius), pointing out that the differences rest chiefly on the form of the third and

fourth perseopods, and on the circumstance that the last-mentioned couple of species

have each five pairs of branchial vesicles, whereas in his own species there are only four

’ ey

THE AMPHIPODA. 27

pairs, none being present on the second gnathopods. Vosseler does not definitely say

that this is the case with the form which he has examined, but implies it by speaking of

“the four pairs of branchiz situated behind the third to the sixth leg,” in evident

allusion to Chun’s mode cf expression, “four pairs of branchial sacs between the third

to the seventh pair of thoracic feet.” In the specimen from the Bay of Biscay, which

specimen I dissected with a special view to this point, the second gnathopods are beyond

doubt provided with branchial sacs, and this specimen agrees in one respect better with

Dr. Vosseler’s figure than with my own, for in the fourth peraeopods I have represented

the sixth joint rather shorter than the fourth, but Vosseler, who describes it as being as

long as the fourth, figures it as longer, which it really is in the instance most recently

examined. Chun assigns a spine-process to the third joint of the third pereeopods, using

this as a mark to distinguish his §. Bovallii from the §. Clausi of Bovallius. But no

such spine is found in S. Rattrayi. Under all these circumstances it seems unsafe to

cancel the latter name in favour of S. /episma, however the differences of description

might be conjecturally explained away.

Length of specimen, first antennze included, 3°3 mm.

Occurrence: 320. 75 to 0 fathoms. 1 specimen.

10. Scrna LEPIsMA (Chun). (Plate 3B.)

1889. Fortunata lepisma, g, Chun, Math. u. Naturw. Mittheilungen Ak. Berlin, Bd. xly. p. 533 (343),

pl. 8. fig. 10.

1889. Scina Bovallii (and Bovalli), Chun, Zool. Anzeiger, Jahrg. xii. No. 309, p. 308,

It was not till after I had completed, as I thought, my present review of this family

that an example of Chun’s interesting species came to light in a bottle containing some

larger Hyperiids. The very close agreement with Chun’s description in almost all

particulars of moment will be seen from the figures of details here given (Pl. 38). The

telson, however, is not rounded off, but narrowly triangular, and there are small branchial

a vesicles to the second gnathopods as well as to the four following pairs of limbs. The

oa mouth-organs are very small, the upper lip very unsymmetrically bilobed, and the twin

plates of the maxillipeds are not drawn out into sharp apices. The outer margin of the

large joint in the flagellum of the first antennz shows seven or eight teeth. In the

first and second perzopods the fifth joint, which is longer than the fourth or sixth, is

a: conspicuously glandular, In the remarkable third pair the short tooth on the third joint

; is minute as in various other species, but the shortness of the fourth joint, in comparison

_ with the slender curved hand, and the elongated finger are highly distinctive. In the

fourth pair the second joint is in our specimen not quite so long as the fourth and fifth

combined, thereby slightly differing from Chun’s description.

Length of the specimen, a nearly full-grown male, 455 mm. Chun’s specimen

measured 5mm. It was a male in the same condition as the present example with

regard to the overlapping second antenne, and was taken at a depth of 1600 m. between

Tenerife and Gran Canaria.

Occurrence: 36%. 300 to 0 fathoms. 1 specimen.

SECOND SERIES.—ZOOLOGY, VOL. X. 6

28 REV. T. R. R. STEBBING—BISCAYAN PLANKTON :

11. Scrya BOREALIS (Sars).

1882. Clydonia borealis, Sars, Christiania Vidensk. Forhandlinger, No. 18, p. 76, pl. 3. fig. 1 a-0.

1887. Tyro borealis, Bovallius, Bihang t. K. Svenska Vet.-Akad. Handl. Bd. xi. No. 16, p. 4.

1887. Tyro borealis, Bovallius, K. Svenska Vet.-Akad. Handl. Bd. xxi. No. 5, p. 16.

1888. Tyro borealis, Stebbing, ‘ Challenger? Amphipoda, Reports, vol. xxix. p. 538.

1888. Scina borealis, Stebbing, ‘ Challenger? Amphipoda, Reports, vol. xxix. p. 1272.

1889. Scina borealis, Chun, Zool. Auzeiger, Jahrg. xii. No. 309, p. 309.

1890. Scina borealis, Sars, Crustacea of Norway, vol. 1. pt. 1, p. 20, pl. 8.

1895. Scina borealis, Stebbing, Trans. Zool. Soc. London, vol. xiii. pt. 10, p. 350.

1896. Scina borealis, Garbowski, Denkschr. k. Akad. Wien, Bd. lxiii. p. 99 (63).

1901. Scina borealis, Vosseler, Amphipoden der Plankton-Exp. p. 108.

A very imperfect specimen apparently referable to this species was obtained at Station

34e, It agrees with the species described and figured by Sars in the characters of the

third pereeopods, and in the peculiarity of having the second joint of the fourth

pereeopods produced into a tooth. The first antennze were missing; without these it

measures 6°25 mm.

Another specimen was obtained at Station 27a. It was not in perfect condition, but

the first antennee, third perzeopods, and first uropods were in agreement with the characters

assigned by Sars.

Occurrences: 27 a. 1250 to 0 fathoms. 1 specimen.

34e. 750 to 500 fathoms. 1 specimen.

Scinidee too young for identification occurred in the following hauls :—

25k. 50 to 0 fathoms. 36g. 200 to 0 fathoms.

30f. 75 to 0 a8 210. 200 to 100 ,,

21h. 100 to 0 5 ,

Fam. LANCEOLID2.

1840. Hypérines ordinaires, M.-Edwards, Hist. Nat. Crust. vol. ili. pp. 74, 77.

1862. Hyperide, Bate, Brit. Mus. Catal. Amph. pp. 287, 304.

1887. Lanceolide, Bovallius, Bihang t. K. Svenska Vet.-Akad. Handl. Bd. xi. No. 16, p. 5.

1887. Lanceolide, Bovallius, K. Svenska Vet.-Akad. Handl. Bd. xxi. No. 5, p. 27.

1888. Lanceolide, Stebbing, ‘ Challenger? Amphipoda, Reports, vol. xxix. p. 1301.

1900. Lanceolide, Sars, Norwegian North Polar Expedition, Crustacea, p. 14.

1900. Lanceolide, Chevreux, Amphipodes de |’ Hirondelle, p. 134.

1901. Lanceolide, Vosseler, Amphipoden der Planktcn-Exp. p. 127.

The family is still limited to a single genus. ; ,

Lanceona, Say, 1818.

This name was reinstated by Bovallius in 1885, after having been long merged in

Hyperia by Milne-Edwards and others, and in Vibilia by Spence Bate. Had it been

really identical with either of those genera, it must still have been upheld by reason of

its priority over both of them.

THE AMPHIPODA. 29

Six species were added to the genus by Bovallius in 1885, but of these in 1887 he

withdrew Lanceola curticeps as a synonym of L. felina. Of four species added by

myself in 1888, I now propose to withdraw Z. Suhmi as belonging on a balance of proba-

bilities to the earlier L. serrata of Bovallius. This leaves at present nine species to be

distinguished in the genus, exclusive of Z. Murrayi, Norman (see page 30). It is

possible that Say’s Z. pelagica may be identical with the Z. Sayana of Bovallius, since

the chief mark of distinction rests on a measurement which, at the date when Say

wrote, was not likely to have been made with much exactness. Between the antarctic

L. australis and the arctic L. serrata there is also a rather conspicuous resemblance.

Prp. 5 (said to be) not shorter than prp.2. . . . . . 1. . . 1. Li pelagica, Say.

Prp. 5 shorter than prp. 2. 2.

of, Enpecmowobvously shorten thaniprp.4. . . 5 0 2 . . « ..5 2. Ee Lovéni, Bovallius.

| rp. 3 obviously shorter than prp. 4. 3.

Rostrum conspicuous. 4.

Rostrum not conspicuous. 5.

(Telson as long as peduncle ofurp.38 . . . . . . . 2... . . 8. ZL. Sayana, Bovallius.

s | Telson much shorter than peduncle of urp. 3. |. ww 1... 4 ZL. felina, Bovallius.

5, | Prp. 4), Slnoirtier Tren eh 2) he leeds os Py oe 5. L. Clausii, Bovallius.

°* | Pep. 4 longer than prp. 2. 6.

6 i. with medio-dorsal teeth. 7.

Pleon without medio-dorsal teeth. 8.

Body not carinate . . . oe 8) | nr mers, (O1 2enser7ara, Bovallius:

i cay medio-dorsally soled) « Sos + + 1S en eas Ae SOE) austeale, Stebping.

8 .. aslong aspeduncleofurp.3 . . . ...... =... 8 ZL. pacifica, Stebbing.

Telson much shorter than peduncle of urp. 3. 2 1. ww... OD LZ. estiva, Stebbing.

12. LANcEoLA astiva, Stebbing.

1888. Lanceola estiva, Stebbing, ‘ Challenger’ Amphipoda, Reports, vol. xxix. p- 1309, pl. 1538.

Two specimens occurred in the collection. The whole integument is pellucid, in

delicacy almost like tissue-paper. The front of the head is obtuse, without rostrum, and

it is doubtful whether the medio-dorsal line of the body is at any part angled, though a

little lateral pressure might easily give a specimen the appearance formerly described of

being both rostrate and subcarinate. One of the present specimens, on being dissected,

+ _ showed otherwise minute agreement with the much larger example described in the

- ‘Challenger’ Reports, except that the fifth joint in the second antenni proved to be

_ rather longer than the fourth instead of scarcely so long, and the spines or spinules on

the first gnathopods were less numerous.

Of the species described by Bovallius, both Z. serrata and L. Lovéni are, like L. estiva,

hyaline, with the integument very thin and finely reticulated. All the three have the

pereeopods slender and most of them elongate. The general similarity, indeed, makes it

desirable that the distinctive features of each should be carefully noted.

The character of the rostrum is difficult to use. Of Z. serrata Bovallius says, “ the

obtuse rostrum is scarcely half as long as the rest of the head”; and of LZ. Lovéni, “ the

obtuse rostrum is almost as long as the rest of the head.” What shape of rostrum is

30 REV. T. R. R. STEBBING—BISCAYAN PLANKTON :

intended cannot, I think, be gathered from the figures of the head in lateral view.

Lanceola serrata, however, is sharply distinguished from its two companions by the

projecting medio-dorsal teeth of the first four pleon-segments forming a serrate crest, to

which the species owes its name, and by the much more elongate telson, which is not

much shorter than the peduncle of the third uropods, whereas in the other two it is only a

little more or less than half the length of that peduncle. On the other hand, L. Lovént

is with equal sharpness separated from the other two species by its first gnathopods, in

which the hand or sixth joint is nearly as broad as it is long, much more than half the

width of the preceding joint, “ very thick, swollen, the anterior margin semicircular,”

and by the fact that the third and fourth pereopods are almost equal in length. In

both limbs alike Bovallius states that the fourth joint is shorter than the sixth. In

L.estiva, as in L. serrata, the fourth joint is longer than the sixth in the third pair,

but shorter than the sixth in the fourth pair.

The length of each specimen, including the first antennze and uropods, was about

15 mm.

Occurrences: 30, mesoplankton trawl. 2000 to 1000 fathoms. 1 specimen.

367. 350 to 0 fathoms. 1 specimen.

13. Lancrona pactrica, Stebbing.

1888. Lanceola pacifica, Stebbing, ‘Challenger’ Amphipoda, Reports, vol. xxix. p. 1302, pls. 151, 152.

This species undoubtedly comes very near to LZ. Sayana, Bovallius; but whereas the

latter has a pronounced triangular rostrum, and is “distinguished from its allies by the

angular prominences of the integument of the sides ” of the perzeon, the present species

has a small obtuse rostrum (as observed in the Pacific specimen) or is quite without one

(in the examples from the Bay of Biscay), and is devoid of the lateral angular prominences

of the perzeon. Here also the back of the perzeon is rounded, except for faint traces of

an interrupted carina on the first three segments. In L. Sayana the keel appears to

extend all along the body, as Bovallius writes, ‘the dorsal line forms an obtuse keel,

which is interrupted between the segments.” He further states that “the mtegument

is thick, calcareous,” epithets which will not apply to the covering of L. pacifica.

The length of one specimen, from apex of first antenna to end of third uropod,

12-5 mm.; of the other, the antenne not included, 18°25 mm.

Occurrences: 527’. ?100 to 0 fathoms*. 1 specimen (12°5 mm.).

34 6. 100 to 0 fathoms. 1 specimen (13:25 mm.).

Lanceola Murrayi, Norman, described and partially figured in the ‘Annals and

Magazine of Natural History,’ ser. 7, vol. v. p. 185, pl. 6. figs. 1-4 (1900), might apparently

be united with Lanceola felina, Bovallius, but for the difference that the first perzeopods

have the hand longer, instead of shorter, than the wrist. The amount of this difference

cannot be estimated, as there is no detail figure of the limb for either species.

* Cf. Dr. G. H. Fowler’s “ Methods and Data,” supra, p. 11.

CS ee

THE AMPHIPODA. 31

Fam. VIBILIID 4. Se

This family is still content with a single genus.

Visita, Milne-Edwards, 1830. ;

The species assigned to this genus are now rather numerous, but the material in the “9s 9 >

present collection is too small to justify a full discussion. The recent additions are Nw s

_F. erratica, Chevreux, 1892; V. Bovallii, Bonnier, 1896; V. hirondellei, dentata,

and grandicornis, described by Chevreux in 1900; and V. cultripes by Vosseler in

1901.

14. Viprrra armara, Bovallius.

1887. Vibilia armata, Bovallius, Bihang t. K. Svenska Vet.-Akad. Handl. Bd. xi. No. 16, p. 10.

1887. Vibilia armata, Bovallius, K. Svenska Vet.-Akad. Handlingar, Bd. xxi. No. 5, p. 69, pl. 10.

figs. 15-22.

1901. Vibilia armata, Vosseler, Amphipoden der Plankton-Expedition, p. 125.

_ This species belongs to a group in which the postero-lateral angles of the sixth pleon-

segment are produced backward so as partially to overlap the peduncles of the third

‘uropods. Within that group it is distinguished by the second gnathopods, which have

the anterior apex of the sixth joint acutely produced.

_ The head is very obtusely rostrate. ‘The fifth and sixth segments of the pleon are

coalesced. The eyes are large, dark, broader above than below. ‘The first antennz are

rather sharply tapering. ‘The dissected specimen differed from that described by

Bovallius in having six spines instead of only three along the convex margin of the hand

in the first gnathopods. The eggs numbered about a hundred.

4 Length, including the first antenne, about 8°75 mm.

_ By this capture the known distribution of the species is extended considerably

Occurrence : 31d. 50 to 0 fathoms. 2 specimens.

16. VIBILIA PROPINQUA, Stebbing.

1888. Vibilia propinqua, Stebbing, ‘ Challenger’ Amphipoda, Reports, vol. xxix. p. 1279, pl. 147.

1901. Vibilia propingua, Vosseler, Amphipoden der Plankton-Expedition, p. 124.

The specimen closely agrees with the description given in the ‘Challenger’ Report,

¢ that the apex of the telson is obliquely truncate, which must be an accidental

ity. Dr. Vosseler, who had several specimens at command, found that the

im was variable, being sometimes obsolete even in large specimens. He speaks of

svery nearto V. Jeangerardii, Lucas, and V. viatrix, Bovallius. From the latter of

shese it is distinguished by having the fifth and sixth segments of the pleon coalesced,

and from the former by a very differently shaped telson. In the first gnathopods of

V. propinqua the sixth joint has no such rounded projecting apex of the hind margin

og REY. T. R. R. STEBBING—-BISCAYAN PLANKTON :

as Bovallius figures for Vibélia viatrix. From another near-standing species, V. hiron-

dellei, Chevreux, V. propinqua is separated by the much shorter process of the fifth

joint in the second gnathopods, this process in Chevreux’s species reaching even beyond

the hind margin of the following joint.

The total length of the specimen was about 7°5 mm.

The species having been originally taken in the Pacific Ocean, some surprise might

have been felt at its occurring in the Bay of Biscay, but in the interval Dr. Vosseler has

reported it from the Sargasso Sea, the Guinea current, and the south equatorial

current.

Chevreux (‘Amphipodes de l’Hirondelle,’ p. 125, 1900) has pointed out that the

ordinary form of V. Jeangerardii, Lucas, has the last joint shorter than the penultimate

in the fifth perseopods and the fifth and sixth segments of the pleon only separated

laterally, whereas in the form assigned to that species by Bovallius these segments are

distinct all across the back, and the finger of the fifth perzeopods is stated to be much

longer than the preceding joint.

Occurrence: 36¢. 25 to 0 fathoms. 1 specimen.

Fam. PHRONIMID2.

Puronima, Latreille, 1802.

1802. Phronima, Latreille, Hist. Nat. des Crustacés et des Insectes, vol. ii. p. 38.

1889. Phronima, Bovallius, K. Svenska Vet.-Akad. Handlingar, Bd. xxii. No. 7, p. 342.

1895. Phronima, Chun, Bibliotheca Zoologica, Heft xix. p. 107.

1900. Phronima, Chevreux, Amphipodes de |’ Hirondelle, p. 136.

1901. Phronima, Vosseler, Amphipoden der Plankton-Exp. p. 1.

16. PHRONIMA SEDENTARIA (Forskal).

1775. Cancer sedentarius, Forskal, Descriptiones Animalium in Itin. Orientali, pp. xxi, 95.

1803. Phronima sedentaria, Latreille, Hist. Nat. des Crustacés et des Insectes, vol. vi. p. 281.

Latreille, in 1802, gives Cancer sedentarius as “exemple” of the genus Phronima,

but does not actually print the specific name in its feminine form till the following

year.

In the present collection there is a small specimen taken at Station 385 y between the

surface and 75 fathoms, and another taken at 35 f between the surface and 100 fathoms,

both being apparently young males of this species. This material does not seem to

justify a discussion of the controversy which has arisen of late years as to the species in

this genus. In the century that has elapsed since the genus was instituted, writer after

writer has been tempted to establish new species, each being in general less ready

to accept the validity of his predecessor’s innovation than to follow his example by

making a fresh one. A study of the works referred to above will show the intrinsic

difficulties of the subject.

THE AMPHIPODA.

MS)

os]

Fam. HYPERIID &.

1852. Hyperide (part.), Dana, Amer. Journ. Sci. & Arts, ser. 2, vol. xiv. p. 314.

1886. Hyperiide, Sars, Norwegian North-Atlantic Exp. vol. xv. Crustacea, pt. ii. p. 36.

1888. Hyperide, Stebbing, ‘ Challenger’ Amphipoda, Reports, vol. xxix. p. 1372.

1889. Hyperiide, Bovallius, K. Svensk. Vet.-Akad. Handlingar, Bd. xxii. No. 7, p. 74.

1890. Hyperude, Sars, Crustacea of Norway, vol. i. p. 5.

1900. Hyperide, Chevreux, Amphipodes de I’ Hirondelle, p. 138.

1901. Hyperiide, Vosseler, Amphipoden der Plankton-Exp. p. 51.

In the later works above cited there will be found a large fund of information

respecting this family, to which Dr. Bovallius especially has paid minute attention.

The species represented in the present collection are not numerous enough to justify

a discussion of the whole group.

Hypertia, Latreille, 1823.

1823. Hyperia, Latreille (in Desmarest), Dict. Sci. Nat. vol. xxviii. (Malacostracés).

1901. Hyperia, Vosseler, Amphipoden der Plankton-Exp. p. 56.

Between the first and latest writers on this genus there is an immense array, and, as

Bovallius explains, the type species was known some sixty years before the genus

received its present name.

17. HypEria Lvzonl, Stebbing.

1888. Hyperia luzoni, Stebbing, ‘ Challenger’ Amphipoda, Reports, vol. xxix. p. 1382, pl. 166 a, and

“young (?),” p. 1384.

1889. Hyperia luzoni, Bovallius, K. Svensk. Vet.-Akad. Handlingar, Bd. xxii. No. 7, p. 212.

1901. Hyperia luzoni, Vosseler, Amphipoden der Plankton-Exp. p. 64, pl. 5. figs. 16-28.

1901. Hyperia luzonii, Lo Bianco, Mittheil. Stat. Neapel, vol. xv. pp. 424, 446.

The original descriptions referred to a single male specimen, 3°75 mm. long, from the

r China Sea, off Luzon, lat. 16° 35’ N., and a specimen less than 3 mm. long, which, as

i Vosseler points out, is doubtless a young male, from the South Pacific, lat. 38° 6’ S.

Vosseler had at his command 22 specimens, including young males and females and

“Many adult females, showing an extensive range in the Atlantic.

_ The species is represented in the present collection by a female 2°5 mm. long, which

aust be regarded as mature, seeing that it contained some four-and-twenty large eggs.

In several respects this species resembles that described by Bovallius and by Vosseler as

_ Hyperia Fabrei (Milne-Edwards), from which, however, it is distinguished not only by

- yarious minute details of armature, but by two tolerably conspicuous features, in that

the second joint of the third, fourth, and fifth perseopods is here far less dilated, while

the proportion which the telson bears to the peduncle of the last uropods is far greater.

_ The latter distinction is modified, but not cancelled, by Vosseler’s observation that in

_ 4. Fabrei the telson of the female is considerably larger than that of the male. In this

latter species, Vosseler gives the extreme length of the animal as 4 mm. ; Bovallius gives

5) REY. T. R. R. STEBBING—BISCAYAN PLANKTON:

the length as varying from 4t06 mm. But the original Lestrigonus Fabrei of Milne-

Edwards is said to be “long d’environ cing lignes,” equivalent to 10°5mm. From the state

of knowledge at the time when Milne-Edwards was writing, it was scarcely to be expected

that either his description or figure would contribute much of the detail now required

for discriminating species of this genus, but the disparity of size is so great as to make

the identification of his form from the Indian Ocean with that since found in the

Atlantic, to say the least, highly improbable. I therefore propose to distinguish the

H. Fabrei of Bovallius by the new name Hyperia Vosseleri.

In H. luzoni, according to Vosseler, the fifth joint in the first pereopods is armed

with a single stiffly outstanding seta, in the second pair with two such sete, and in

each of the three following pairs with one slender seta. My own observation agrees

with this account, except that I find two of the setz or spines on the fifth joint in

the first as well as in the second perzeopods. They are found also in both first and

second perseopods of H. Vosseleri. In that species the spine is wanting on the fifth

joint of the last three pairs of perzeopods. But also in the ‘ Challenger’ specimens of

fi. luzoni this spine was wanting.

Occurrence: 384d. 100 to 0 fathoms. 1 ovigerous @.

Hyrerrioiprs, Chevreux, 1900.

1900. Hyperioides, Chevreux, Amphipodes de l’Hirondelle, p. 143.

1901. Parahyperia, Vosseler, Amphipoden der Plankton-Expedition, p. 56 (without definition).

M. Chevreux gives the following definition of the genus :—‘ Body much more com-

pressed than in the species of the genus Hyperia. Head prolonged anteriorly, above

the insertion of the upper antennz. Eyes occupying only the upper part of the head.

Palp of the mandibles remarkably long. Basal part of the maxillipeds very elongate;

internal lobe little developed. Carpus [fifth joint] of the gnathopods strongly produced

in both pairs. Feet of the fifth and sixth pairs [third and fourth perzeopods] very

long, equal; feet of the seventh pair [fifth perzeopods] much shorter. Uropods rather

elongate. Telson much broader than long, semicircular.”

The definition, as it stands, applies to a single species and in fact to only one sex of

that species. Here, as in some other members of the Hyperiide, it proves that the

female is devoid of a mandibular palp. But there are probably two species already

known, which are so closely allied that the generic character must be further modified

so as to admit them side by side. Dr. Vosseler, while studying the same form as

that which M. Chevreux has named Hyperioides longipes, was so struck by its resem-

blance to the ‘ Challenger’ species Hyperia sibaginis that he described it under that name.

Unaware at the time of M. Chevreux’s recently published generic title, he suggested

in his own work the designation Parahyperia as suitable for marking the rather fine

distinctions by which the new genus is separated from Hyperia. Also he suggested

that the European form might have to be called Hyperia sibaginis var. longipes or simply

Hyperia longipes, thus not insisting on his proposal of a new genus Parahyperia, but

lighting upon the very same specific name as that already used by M. Chevreux,

THE AMPHIPODA. 35

But the effect of admitting Hyperia sibaginis into the genus Hyperioides will be to deprive

that genus of one of its most striking characters, “eyes occupying only the upper

part of the head.” For the figure in the ‘Challenger’ Report, which has the indepen-

dent guarantee of Dr. Bovallius, shows the eyes covering the cheeks as usual in

Hyperia. In H. longipes there is always a considerable part of the cheek on which no

ocelli are abutting. Unless, therefore, the figure of the Pacific form is erroneous, this

disposition of the ocelli will furnish an important specific distinction, but cannot be

retained in the definition of the genus.

The front of the head is blunt, so that there is no question of a rostral prolongation

in advance of the first antennze, and the projection apparent in lateral view is almost

confined to the male, the head in the female being on the whole strongly truncate in

front, presenting, as Dr, Vosseler says, “in lateral view a form quite unusual fora species

of Hyperia, that of a genuine ¢éte carrée.”

18. HyPERIOIDES LONGIPES, Chevreux.

1900. Hyperioides longipes, Chevreux, Amphipodes de l’Hirondelle, p. 143, pl. 17. fig. 2.

1901. Hyperioides longipes, Lo Bianco, Mittheil. Stat. Neapel, vol. xv. pp. 422, 447.

1901. Hyperia sibaginis, Vosseler, Amphipoden der Plankton-Expedition, p. 60, pl. 7. figs. 6-20

(Parahyperia?, p. 56, Hyperia sibaginis var. longipes, or Hyperia longipes, p. 63).

1903. Hyperioides longipes, A. O. Walker, Ann. & Mag. Nat. Hist. ser. 7, xii. p. 229, pl. 19. figs. 7-13.

Excellent figures and descriptions of the species have been given by M. Chevreux,

Dr. Vosseler, and Mr. A. O. Walker, F.L.S. The only addition of importance to insist

on is the circumstance already noted that in the female the mandible is without a palp.

_ Dr. Vosseler, in describing the female, speaks of the mandibles as having a three-jointed

_palp, but he gives references to figures of the mandible which in the explanation of his

plate are attributed to a male. It may be inferred, therefore, that identity of the mouth-

organs in the two sexes was presumed by him, as it had been by M. Chevreux in defining

4 the genus. Claus, in ‘ Die Platysceliden,’ p. 3 (1887), contrasting “die Hyperinen ” with

_ “dic Gammarinen,” says boldly of the former that “the mandible carries a three-jointed

_ palp only in the male sex.” In response to this, Dr. Bovallius (Mon. Amph. Hyperiidea,

_ p. 158, 1889) declares that in the female of Hyperia medusarum (O. F. Miiller), called

_H. spinipes by Boeck, the mandibles are exactly like those in the male, but a Jittle more

robust, and he gives a drawing of these organs in the female of this typical species on

Bpurpose to show the three-jointed palp. This palp is present likewise in the female of

| Hyperia galba (Montagu). On the other hand, in the three ‘ Challenger’ species Hyperia

_luzoni, H. dysschistus *, and H. schizogeneios, the females show no mandibular palp, and

this is the case also in the two species recently described by Dr. Vosseler as H. macro-

phthalma and ZH. hydrocephala. The last-named author suggests that such species should

be grouped in a subgenus. He has further observed that in H. Fubrei, Milne-Edwards,

the mandibles of the female are variable, sometimes having no palp and at others one

- that is small and uniarticulate.

* A. O. Walker now identifies this with Hyperia bengalensis (Giles), in ‘ Report on the Amphipoda collected by

Professor Herdman at Ceylon,’ p. 235 (1904).

SECOND SERIES.— ZOOLOGY, VOL. X. y/

36 REY. T. R. R. STEBBING—BISCAYAN PLANKTON :

There still remain some species of Hyperta in which the mandibles have been

definitely described for the male only, so that a subdivision of the genus dependent on

the mandibular character in the two sexes cannot for the moment be completely carried

out.

It should be borne in mind that in Hyperioides longipes, though the fifth joint is

produced in both pairs of gnathopods, it is less so in the first than in the second. The

elongate third and fourth pereopods have the fourth joint shorter than the fifth, but in

the shorter fifth pair the fifth joint is a little shorter than the fourth. The third uropods

have a striking appearance by reason of the deep denticulate emargination at the upper

part of the inner border in the outer ramus, which is rather longer than the inner one.

This character becomes more conspicuous in proportion to the size of the specimen. The

almost semicircular telson can scarcely be relied on as furnishing a permanent generic

character, since Hyperia Fabrei, Milne-Kdwards, has a completely similar telson, while

other species of the genus have the telson triangular.

The length of measured specimens varied from 2°5 mm. to a little over 5 mm., none

attaining the length of 6 mm. assigned by Chevreux and Vosseler to full-grown males.

This species was obtained in the Bay of Biscay in no less than thirty-two hauls.

There were several males with numerously-jointed antennz, but none in which the

flagellar joints had attained the elongate tenuity characteristic of complete development.

The great majority of the specimens were obtained by hauls between the surface and

100 fathoms. The occurrences are discussed on p. 49.

ParaTHEMISTO, Boeck, 1871.

1871. Parathemisto, Boeck, Vid.-Selsk. Forhandlinger (Christiania) for 1870, p. 87 (7).

1889. Parathemisto, Bovallius, K. Svensk. Vet.-Akad. Handlingar, Bd. xxii. No. 7, p. 248.

1890. Parathemisto, Sars, Crustacea of Norway, vol. i. p. 10.

1901. Parathemisto, Vosseler, Amphipoden der Plankton-Exp. p. 80.

The dilated and more or less ovoid fifth joint of the first and second perseopods, by

which in adults the species of this genus and of Huthemisto are so readily distinguished

from Hyperia, does not attain its characteristic shape in very young specimens.

19. PARATHEMISTO OBLIVIA (Kroyer).

1838. Hyperia oblivia, Kroyer, Grénlands Amfipoder, Danske Selsk. Afh. pt. vil. p. 298, pl. 4. fig. 19.

1871. Parathemisto abyssorum, Boeck, Vid.-Selsk. Forhandlinger (Christiania) for 1870, p. 87 (7).

1889. Parathemisto oblivia, Bovallius, K. Svenska Vet.-Akad. Handlingar, Bd. xxii. No. 7, p. 251,

pl. 12. figs. 11-16, and figures in text.

1896. Parathemisto oblivia, Bonnier, Ann. Univ. Lyon, Campagne du ‘ Caudan,’ p. 611, pl. 35. fig. 1.

1898. Parathemisto abyssorum, Fowler, Proc. Zool. Soc. London, p. 583.

1901. Parathemisto oblivia (?), Vosseler, Amphipoden der Plankton-Exp. p. 80, pl. 7. figs. 21-25,

pl. 8. figs. 1, 2.

Without giving all the references, it may suffice here to say that the identification of

Boeck’s P. abyssorum with Kroyer’s species was suggested as probable by H. J. Hansen

in 1887, accepted by Bovallius in 1889, Sars in 1890, and Chevreux in 1900. The

THE AMPHIPODA. a7

variations in size are perplexing, M. Bonnier recording an ovigerous female 10 mm. in

length from a depth of 950 metres in the Bay of Biscay, while Sars speaks of North

Atlantic specimens 17 mm. long, and others wholly agreeing with these except in being

taken at much less depths and in scarcely exceeding a length of 5 mm. Dr. G. H.

Fowler mentions specimens from Valentia, Galley Head, and the Firth of Forth, the

curious fact about which is “that they are all very small, ranging from 2 to 5 mm.;

whereas in the Faeroe Channel they are mostly about 7-10 mm. in length.” Bovallius

gives the length as 5-8 mm.

Boeck makes a dorsal carina characteristic of the genus, and Bovallius describes the

body in this species as feebly carinated, less distinctly in the female than in the male.

This account would not be inconsistent with a disappearance of the carina from very

small or young specimens. Vosseler says of the young specimens which he had

examined that none had any indication of a dorsal carina, nor could I detect any such

indication in specimens of the present collection. Only one of these approached the

length of 4 mm.

Very small specimens, apparently belonging to this genus and perhaps to this species,

have the first and second perzeopods even more like those of Hyperia luzoni than shown

in Vosseler’s plate 8. fig. 1, representing the first peraeopod of a young female

* Parathemisto oblivia?” Since, however, there are other very small species of

Parathemisto, it may be doubted whether the younger forms, measuring from 1 to

2 or 3 mm. in length, can be with any certainty discriminated. A careful study

of adults and young taken together may in future supply marks of distinction

for the young of the several species, but the little isolated specimens of the present

collection do not furnisb materials for such a study. Yet a specimen only 3°5 mm. long,

with articulation in the flagella of the antenne becoming visible and thus indicating an

approach to maturity of the male sex, closely agrees with the figures of P. odlivia given

by Bovallius and Sars, in regard to the telson and uropods agreeing with Sars rather

than Bovallius. In the third perzeopods the fifth joint is rather longer than in the fourth

pair, and there rather longer than in the fifth. Bovallius speaks of all these limbs as

z. equal in length; but Sars qualifies them as subequal.

_ The specimen just referred to was taken at Station 21, at the surface. A specimen of

_ the same size, with antennze doubtful, was obtained at Station 21m, between 500 and

‘ae 400 fathoms. A smaller male occurred at Station 21”, between 150 and 100 fathoms.

___ Asspecimen occurred at Station 210, between 200 and 100 fathoms. Others, for the

- “most part smaller than those mentioned, were taken in various hauls between the

“surface and depths ranging to 100 fathoms. The largest specimen in the collection,

measuring 3°75 mm., was taken at Station 22 e, at the surface.

Z Evuruemisto, Bovallius, 1887.

Be 1889. Euthemisto, Bovallius, K. Svensk. Vet.-Akad. Handlingar, Bd. xxii. No. 7, p. 275.

ae Guérin’s Themisto, 1825, being preoccupied, was changed to Euthemisto by Bovallius

Sein 1887.

3 REV. T. R. R. STEBBING—BISCAYAN PLANKTON:

20. EvTHEMISTO COMPRESSA (Goés).

1866. Themisto compressa, Goés, Ofversigt K. Vet.-Akad. Férhandl. (Stockholm) for 1865, p. 533

(17), pl. 41. figs. 34, 34,

1889. Euthemisto compressa, Bovallius, K. Svenska Vet.-Akad. Handlingar, Bd. xxii. No. 7, p. 305,

pl. 12. figs. 45-57, pl. 13. figs. 32-43.

1890. Euthemisto compressa, Sars, Crustacea of Norway, vol. i. p. 12, pl. 5. fig. 2.

1900. Euthemisto compressa, Chevreux, Amphipodes de l’ Hirondelle, p. 146.

1901. Euthemisto compressa, Vosseler, Amphipoden der Plankton-Exp. p. 81, pl. 8. figs. 11-17.

Bovallius makes Themisto bispinosa, Boeck, a synonym of this species, while Sars,

Chevreux, and Vosseler keep them apart. It should be noted that in Vosseler’s ‘'Tafel-

Erklirung’ the numbering of the figures of these two species is transposed. Sars in

1895 (op. cit. appendix, p. 673) identifies Euthemisto bispinosa with Themisto crassicornis,

Kroyer. The present collection contains only part of a specimen, ending with the third

pleon-segment, a female, measuring from the front of the head to end of fragment 7 mm.

It appears to be sharply carinate along perzeon and pleon, but devoid of projecting dorsal

teeth. It has the character of the first three pairs of pereeopods which the figures of

Sars and Vosseler show to be distinctive of #. compressa from LH. bispinosa.

Occurrence: 32d. 100 to 0 fathoms. 1 specimen,

Fam. PHROSINID2.

Primno, Guérin, 1836.

1836. Primno, Guérin, Magasin de Zoologie, vol. vi. Classe 7, p. 2.

1887. Primno, Bovallius, Bihang till K. Svenska Vet.-Akad. Handlingar, Bd. xi. No. 16, p. 28.

1888. Primno, Stebbing, ‘ Challenger? Amphipoda, Reports, vol. xxix. pp. 164, 1440.

1889. Euprimno, Bovallius, K. Svenska Vet.-Akad. Handlingar, Bd. xxii. No. 7, p. 397.

1900. Euprimno, Chevreux, Amphipodes de 1’ Hirondelle, p. 148.

1901. Euprimno, Vosseler, Amphipoden der Plankton-Expedition, p. 87.

Bovallius substituted Huprimno for the name given by Guérin, ‘‘ because Primno was

previously applied to a genus of Crustacea by Rafinesque-Schmaltz in 1814.” It is true

that the eccentric author referred to, in his ‘ Précis de ses découvertes,’ at the date

named, mentioned along with several others a species Primno lutescens included in his

“Fam. Aselotia and Oniscia.” But he did not define the genus. He did not figure or

describe the species. He did not even say to which of the two indeterminate families

the genus belonged. It is evident, therefore, that Rafinesque’s Primno is of no scientific

importance, and has no claim to supersede the legitimate use of the name by Guérin.

21. PRimNo MACROPA, Guérin.

1836. Primno macropa, Guérin, Magasin de Zoologie, vol. vi. Classe 7, p. 4, pl. 17. fig. 1 a-.

1888. Primno macropa, Stebbing, ‘ Challenger’? Amphipoda, Reports, vol. xxix. p. 1441, pl. 178.

1889. Euprimno macropus, Bovallius, K. Svenska Vet.-Akad. Handlingar, p. 400, pl. 17. figs. 23-40,

pl. 18. figs. 1, 2.

1900. Euprimno macropus, Chevreux, Amphipodes de |’ Hirondelle, p. 148.

THE AMPHIPODA. 39

1901. Euprimno macropus, Vosseler, Amphipoden der Plankton-Expedition, p. 87, pl. 8. fig. 21.

1901. Huprimno macropus, Lo Bianco, Mittheil. Stat. Neapel, vol. xv. pp. 422, 447.

That macropus is a more scholarly form than macropa must be admitted, but the

practice of polishing and improving the names which our scientific ancestors invented

has to my mind the same effect as daylight upon Melrose Abbey, where the rays of the

sun “ gild but to flout the ruins grey.”

Bovallius, referring to the species Primno Latreillei, Menevillei, and antarctica,

established in the ‘ Challenger’ Report, goes on to say, “ After a careful examination of the

material at my disposal I am convinced that these three new species are at most varieties

of the type species, because the chief differences recorded by Stebbing are liable to

great variation, purely individual as well as owing to the age of the animals.” Vosseler

alludes to and apparently accepts this opinion, though without including the names in

the synonymy of the type species. It is, at any rate, a very convenient view to adopt

in dealing with the small specimens contained in the present collection with 3 mm. for

the upper limit of length.

A specimen measuring about 1:4 mm. was obtained between 50 fathoms and the surface

at Station 25 e, this being obviously a very juvenile form. Its want of a mandibular

palp is unimportant, since this deficiency is a permanent character in the female.

Some observations, however, may be offered as to the limbs of the perzeon. The gnatho-

pods have practically the adult form, but the first and second perzeopods differ from

those of the full-grown animal by having the fifth joint much broader than the

sixth, its hind margin ending in a strong apical tooth, while the rest of its armature

is limited to a minute spinule. The third perzopods, as shown in the figure (text-fig. 1),

have the front margin of the broad fifth joint furnished only with three large teeth, the

N d Prp. 3.

} intermediate small ones being wholly absent. Both limbs agreed in their armature,

a symmetry which Dr. Bovallius found to oceur only once in fifteen specimens

which he examined of various sizes from 1°5 to 12 mm. in length. The fourth

perzeopods have the front margin of the fifth joint armed only with an apical tooth.

The fifth pair are very small and peculiar. The second joint is straight, narrow,

slightly tapering to the distal end, and longer than all the remainder of the limb. This

consists of a short third joint followed by a blade-like narrowly ovoid but distally pointed

. _ piece, which may be taken to represent the last four joints in one.

The pleopods at this stage have three-jointed rami.

40 REY. T. R. R. STEBBING—BISCAYAN PLANKTON:

The uropods are of special interest. After discussing the variations in the third

perzeopods, Dr. Bovallius observes, “In the form and serration of the uropoda there

is a similar variation, but more connected with the age of the animal, so that the

older animals which have attained a length of 10 or 12 mm. have the uropoda

comparatively much broader than in the young, less distinctly serrated, and hardly

emarginated at the apex, while the young have the first and second pairs very narrow,

sharp-pointed, and finely serrated, and the third pair only a little dilated, sharp-pointed,

and deeply emarginate.”

In the specimen here described, which is a very little shorter than the smallest of

those examined by Bovallius, a completely new relation comes into view. All the

uropods are, as Bovallius says, and as the figure (text-fig. 2, p. 39) depicts, sharp-pointed,

but there is no perceptible serration and no emargination. The first pair is slightly the

longest, though not reaching so far back as the third. The second is considerably shorter

and slightly narrower than the other two, and has some way above the middle of the outer

margin a minute spinule. The third pair have a slender spine-like outer ramus, proved

to be a ramus and not a spine by the muscles attached to it. The place of insertion of

this ramus shows that the peduncular part of the uropod is slightly longer than the

completely coalesced inner ramus, which is much broader than the outer but not fully

twice as long. In the adult there appears to be no reminiscence of this outer ramus,

unless the almost terminal emargination of the broad plate into which the uropod

eventually develops indicates the place of insertion. Anyone observing the uropods

and telson of this young Primno on the hinder part of the pleon detached from the rest of

its body might well be excused for determining them as belonging to one of the

Scinidee.

Occurrences: 25e. 50 to 0 fathoms. 1 specimen, about 1:4 mm. long.

BLAS aes 3 " il NS 2°5 mm. long.

Shds ss s A i, 3 mm. long.

32m. 75 to 0 fathoms. 1 R young.

30h. 100 to 0 fathoms. 1 ss 3 mm. long.

Fam. TYPHID&.

BRACHYSCELUS, Bate, 1861.

1861. Brachyscelus, Bate, Ann. & Mag. Nat. Hist. ser. 3, vol. viil. p. 7.

1888. Brachyscelus, Stebbing, ‘ Challenger’? Amphipoda, Reports, vol. xxix, p. 1543.

22. BRACHYSCELUS MEDITERRANEUS (Claus), 1887.

1887. Thamyris mediterranea, Claus, Die Platysceliden, p. 60, pl. 16. figs. 11-18.

1888. Brachyscelus mediterranea, Stebbing, ‘ Challenger? Amphipoda, Reports, vol. xxix. p. 1556.

1900. Brachyscelus mediterraneus, Cheyreux, Amphipodes de |’Hirondelle, p. 154.

1900. Brachyscelus crustulum, Norman, Ann. & Mag. Nat. Hist. ser. 7, vol. v. p. 134.

1903. Brachyscelus mediterraneus, A. O. Walker, Ann. & Mag. Nat. Hist. ser. 7, vol. xii. p. 231.

A single specimen, 4°5 mm. long, agrees well with the figure assigned by Claus to

THE AMPHIPODA AND CLADOCERA. AL

this species, except that in the fifth pereeopods the fifth joint is not shorter but longer

than the sixth. It does not help to decide the question, which Claus himself leaves

doubtful, as to whether his mediterraneus should be regarded as a synonym of his earlier-

named globiceps. Norman may very well be right in considering it to be the young

of B. crusculum, Bate.

' Occurrence: 310. 50 to 0 fathoms. 1 specimen.

23. BRACHYSCELUS sp.

The collection contains a representative of this genus only 2mm. in length. The

branches of the pleopods are four-jointed and the mouth-organs extremely delicate. It

is much smaller than any species hitherto described, and, though all the limbs are well

developed, the probability remains that it may be a young form of a species already

named—such, for example, as B. globiceps or B. mediterraneus (Claus). The third

perzeopods have the second joint elongate-oval, with two spinules on the front margin,

which is decidedly convex. The second joint is much more broadly oval in the fourth

pair, and less narrowed below than in many species; the fifth and sixth joints have the

usual serration of the front margin. The fifth perseopods have the second joint like that

in the ‘ Challenger’ species, B. Bovallii, long and narrow, much wider above than below.

Here, however, the remaining joints are differently proportioned, increasing in length

from the third to the sixth, these with the minute finger together about equalling the

length of the second joint. The telson is broad, apically subacute, not reaching so far

back as the outer branch of the third uropods, which is considerably shorter than the inner

branch. A rather larger specimen and one only about 1 mm. long were also obtained.

Supposing these forms to be juvenile, it should be noticed that there is no

_ reminiscence of the strange character described by Bate for the fourth perzeopods of the

larval B. erusculum.

Occurrences: 24g. 0 fathoms. 1 specimen, 1 mm. long.

21e. 0 fathoms. 1 specimen, 2 mm. long.

33d. 100 to 0 fathoms. 1 specimen, 2°5 mm. long.

ENTOMOSTRACA.—Section BRANCHIOPODA.

CLADOCERA.

Tribe ONYCHOPODA.

Fam. POLYPHEMID2.

Evapbneg, Lovén, 1836.

1836. Evadne, Lovén, K. Vet.-Akad. Handlingar (Stockholm) for 1835, p. 1.

1902. Evadne, Sars, On the Polyphemide of the Caspian Sea, Ann. Mus. Zool. Acad. Imp. Sci.

; St.-Pétersbourg, vol. vii. p. 10 (extract).

+. The earliest and one of the latest references to this well-known genus will suffice for

the present purpose. Sars remarks that it is very abundantly represented in the

Caspian Sea, “ whereas in the Oceans hitherto only three very sharply defined species

42 REV. T. R. R. STEBBING—BISCAYAN PLANKTON:

are known, viz., EL. nordmani Lovén, #. spinifera Miller, and £. tergestina Claus.”

Of the last he has convinced himself “ that it is very distinct from the other two marine

species, being especially distinguished by the fact, that the exopodite of the 2 middle

pairs of legs carries 3 well-developed setz, a character not found in any other known

Evadne.” Thus these three species in their chronological order offer a synoptic arrange-

ment easy to remember :—

Hixopod of the || «with one|seta) 22)..res.eseeeeeeeee ree 1. E. Nordmanni, Loven.

third pair with ‘two seteel:. Q.cns ss eee eeeeee reer 2. E. spinifera, P. EK. Miiller.

of legs. With three lseuac eee eee ee ee nene eee 3. EH. tergestina, Claus.

1. EvapNe NorpMANNI, Lovén.

1836. Evadne Nordmanni, Loven, K. Vet.-Akad. Handlingar (Stockholm) for 1835, pp. 1-29, pl. 1.

1850. Evadne Nordmanni, Baird, British Entomostraca, Ray Soe. p. 114, pl. 17. fig. 2.

1901. Evadne Nordmanni, Lilljeborg, Cladocera Sueciz, in Noy. Act. Sc. Upsal. ser. 3, xix. p. 641,

pl. 86. ff. 4-17.

This species was taken by the ‘ Research’ at thirty-seven Stations, the depth being

specified in eight cases as 0 fathoms, and in most others as between 0 and various depths

down to 100 fathoms, but it is also recorded at Station 34e from between 750 and 500

fathoms, one specimen, and at Station 31d, from between 1000 and 750 fathoms, one

specimen. There were about 170 specimens in all, the majority coming from nine or ten

of the Stations, at which the number ranged from five individuals up to (in one instance)

some dozens. ‘These occurrences are discussed on p. 52.

2. EVADNE SPINIFERA, P. E. Miller.

1867. Evadne spinifera, P. E. Miiller, Danmarks Cladocera, Naturhistorisk Tidsskrift, ser. 3,

vol. v. p. 225, pl. 6. figs. 11-13.

The long spine at the distal apex of the organism, to which the specific name refers, is

an additional and very obvious character for distinguishing this from the preceding

species, in which the apical spine is minute and sometimes evanescent. The two species

may occur together, Miiller’s being apparently much the rarer of the two.

At Station 30m, between the surface and 25 fathoms, two specimens were taken,

along with several of E. Nordmanni. At Station 31 8, between the surface and 50 fathoms,

several specimens were taken of E. spinifera alone.

Occurrences : 30 m. 25 to 0 fathoms. 2 specimens, with #. Vordmanni.

31 6. 50 to 0 fathoms. Several, no #. Nordmanni.

THY ROSTRACA.

Fam. LEPADID&.

CYPRIS-STAGE OF LEPAS PECTINATA, Spengler.

1793. Lepas pectinata, Spengler, Skrifter Naturhist. Selskabet, vol. ii. Heft il. p. 106, pl. 10. fig. 2.

1854, Lepas pectinata, Darwin, Balanidz (Ray Society), pp. 112-114.

1876. Lepas pectinata, Claus, Untersuchungen geneal. Grundlage des Crustaceen-Systems, pp. 84, 87,

pl. 16. fig. 4.

THE THYROSTRACA. 43

1883. Lepas pectinata, Hoek, ‘ Challenger’ Cirripedia, Reports, vol. viii. p. 40.

1891. Lepas pectinata, Gruvel, Contr. d l’étude des Cirrhipédes, p. 114, pl. 28.

1899. Lepas pectinata, Hansen, Die Cladoceren und Cirripedien des Plankton-Expedition, p. 33.

Darwin states that he had examined the pupa of ZLepas pectinata, and found the

surface of the carapace “ marked with curious points of various shapes, often star-shaped,

in parts reticulated, and confluent along the dorsal margin, and in parts lined.” Under

the heading ‘‘ Acoustic Organs,” he says, “ these lead, as described in my former volume,

into a sack, with a bag suspended in it, which is provided with a large nerve, and which

I believe to be the acoustic vesicle. These orifices occur in the carapace, either in the

same position or a little more posteriorly, in the pupee of all Cirripedes. In Balanus

balanoides they are minute, being only sooth [of an inch] in diameter, but are surrounded

with a border: in Conchoderma virgata they are also surrounded by a border: in Lepas

pectinata the orifices are sooth of an inch in diameter, and are very singular from

being seated on rounded prominences, causing the carapace to have two short, blunt

Crustacea, Darwin supposed that these orifices might represent the otherwise missing

anterior antenne in the pupal Cirripede.

On the other hand, M. A. Gravel, in discussing the Cypris-larva of ZL. pectinata says

that “its valves carry at the lower part a sort of strong horn, corresponding to what will

be the adductor muscle of the valves in the adult” (doc. e¢t. p. 115). He maintains for

the Thyrostracan group at large that “hearing has no special organs, since this sense

does not exist in the Cirripedes.” He bases his conclusion on experiments that seem

fairly conclusive for the adult stage, but he does not claim to have observed the effects of

_ them upon larval forms, which would indeed be a matter of considerable difficulty

- (pp. 55, 179). M. Gruvel gives highly magnified figures of the valve-markings in the

Cypris of L. pectinata, of which he says that, roughly speaking, the ornamentation of

the transparent carapace is formed of regularly arranged polygonal thickenings of the

_ chitin, the hexagons or pentagons being marked off by narrow chitinous ribs. This

| ‘f reads like a very different account from Darwin’s. But Darwin accurately describes the

ae appearance under a low magnification, whereas every successive enlargement changes the

pattern, but on the whole produces the impression of more and more uniformity, as the

details in different parts of the valve are more clearly made out.

The single specimen of this Cypvis-larva in the present collection measured 1°25 mm.,

or a twentieth of aninch. When the valves were opened the organs within were no longer

soft, but dry and unyielding. In lateral view, as shown in fig. 3, p. 44, the shape of the

‘carapace is rather striking, from the great height of the rounded upper half, in contrast

with the triangular distal portion, which narrows rapidly to the acute apices. The

greatest height is rather more than half the length. About a third of the length from

the front, and a little nearer the ventral than the dorsal margin, the dark compound eyes

are situated. The ventral margins are for the most part straight and nearly parallel,

_ but not accurately adjusted one to the other, indicating a want of symmetry between the

valves, as noted by H. J. Hansen (/oc. cit. p. 33) for what he supposes to be the pupa of

«SECOND SERIES.— ZOOLOGY, VOL. x. 8

horns in front.” Influenced by the known position of acoustic apparatus in the higher ~

acts ao

s n

wo, kwase

2 id

Ad REV. T. R. R. STEBBING—BISCAYAN PLANKTON :

Lepas anserifera, Linn. The sturdy, slightly hirsute horns, so distinctive of this larva,

project from near the front and the ventral margin. In dorsal view, as shown in the

diagram (fig. 4), they stand out like a pair of ears at right angles to the carapace. The

length of the shell is three and a half times its greatest width or thickness, as measured a

little to the rear of the horns, but not quite three times such width if measured along a line

including the horns. The dorsal margins diverge only a little in front, but for about a

seventh of the total length distally. In the middle of the length, but near the ventral

margins, the round radiated scars of the adductor muscle can, with proper focussing, be

seen through the honeycomb markings of the valves. The appearance of the limbs and

small pleon is indicated in the adjoining figure (fig. 5).

Fig. 4.

As it were plastered against the inside of the valves below the eyes are the long glands

described by Claus as shell-glands, agreeing in structure with that which he figures for the

Cypris-larva of Lepas australis (loc. cit. pl. 16. fig. 2, SD.). In the present form they are

rather more sinuous in shape. The antennz here represented (fig. 6), allowing for the fact

that they are still free, agree very nearly with Darwin’s figure (doc. cit. pl. 30. fig. 8) of the

antenne in the attached Cypris of Lepas australis. The terminal joint, as shown more

highly magnified in fig. 7, has three short and two long sete, and, in addition, a narrow,

excessively transparent ribbon, answering to that which Darwin discusses (loc. cit. p. 118),

and believes “to be a tube of cement-tissue, which thus, sometimes even before the pupa

is attached, independently grows outwards.”

So far as I can discover, none of the authors who have examined this larval form have

supplied a figure of its external appearance, which is sufficiently singular to have a good

claim to such a compliment.

The place of capture was Station 32 a, between 50 fathoms and the surface.

The figures of the carapace in lateral and dorsal view were drawn with the help of a

1-inch objective, those of the antenna and limbs with 43-inch, and the distal part of the

antenna with a }-inch.

THE AMPHIPODA. 45

EXPLANATION OF THE PLATES.

PLATE 2A.

Eusirogenes dolichocarpus, n. g. et. sp.

n.s. Natural size indicated by a line showing the length of the specimen enlarged below.

a.s., a.i. Upper antenna and part of lower antenna.

is. Upper lip.

m.m. Mandibles.

mex. 1, mx, 2, map. First and second maxille and maxillipeds.

gn. 1, gn. 2, prp. 1, 2, 5. First and second gnathopods and parts of first, second, and fifth perzeopods.

urp. 1, urp. 2. First and second uropods.

| In the detail figures the antenne and appendages of the perweon and pleon are drawn to one scale,

__ portions of a.s. and gn. 1 being added on the same scale as the mouth-organs. Parts of the mandibles

are still more highly magnified.

PLATE 2B.

Parascina Fowleri, n. g. et sp.

n.s. Line showing length of specimen enlarged above.

a.s., a.t. Upper and lower antenne.

m.m., mz. 1, mx. 2, mzp. Mandibles, first and second maxille, and maxillipeds.

gn. 1, gn. 2, prp. 2, 3, 4, 5. First and second gnathopods, second, third, fourth, and fifth perzeopods.

_urp. 1, urp. 2, urp. 3, T. First, second, and third uropods and telson.

___ Details of person and pleon magnified to a uniform scale; parts of the two gnathopods more highly

‘magnified ; parts of other appendages still more highly, in agreement with figures of the mouth-organs.

PLATE 3A.

Archeoscina Bonnieri, n. g. et. sp.

n.s. Line indicating natural size of specimen figured below.

.s., a.i. Upper and lower antenne.

. Mandibles.

1, gn. 2, prp. 1-5. First and second gnathopods, first to fifth perzeopods.

, urp. 1, 2, 3. A pleopod and first, second, and third TOL: the telson appearing between the

bases of the third uropods.

All details drawn to the same sale.

PLATE 3B.

Scina lepisma (Chun).

Line showing length of specimen figured to the left.

i. Upper and lower antennz.

u.m., mx. 1,map. Upper lip, mandibles, first maxilla, and maxillipeds.

Details drawn to the same scale.

46 DR. G. H. FOWLER—BISCAYAN PLANKTON :

APPENDIX ON THE DISTRIBUTION OF THE AMPHIPODA AND CLADOCERA.

By G. HERBERT FowueER, 2.A., Ph.D., F.L.S., F.Z.S.

I. THE AMPHIPODA.

WHEN the species captured during the cruise are arranged by hauls, the first thing

noticeable is the comparative rarity of the Amphipoda. They occurred in only 68

(57 per cent.) of the 118 * * comparable hauls,” and were seldom reckoned by more than

one or two specimens per haul.

The various species apparently do not herd together in the way that some organisms

(e. g. Cheetognatha) often do; for of these 68 hauls, only one included four species,

one three species, thirteen two species, and no less than fifty-three (77 p.c.) produced

but a single species.

In the 68 hauls were 22 species (Lusirogenes dolichocarpus coming from a “ non-

comparable” haul); of these, no less than twelve (54 p. e.) occurred in one haul only, five

(22°7 p.c.) in two hauls, one (4°5 p.c.) in three hauls, two (9 p. c.) in five hauls, and only

two species, both evidently common, occurred in more than five hauls. Thus, while there

are a considerable number of species, the nwmber of individuals is small, except in the

two cases mentioned (Hyperioides longipes and Parathemisto * oblivia),

It is probably due to the fact that Amphipoda are comparatively scarce in these waters

that no single species shows any sign of a diurnal vertical oscillation, such as is generally

stated to affect the epiplankton, but which, so far as I am aware, has never been definitely

demonstrated. I have alo plotted the whole captures of Amphipoda Hyperiidea on to

the time-depth tables (cf pp. 583, 54), but even then can see no certain indication of a

nocturnal rise.

As to the distribution of the individual species recorded elsewhere (even when specialists

are agreed upon the nomenclature, which is by no means always the case), it is most

difficult to obtain information as to the conditions under which the capture was made,

even by comparatively recent expeditions. Most naturalists seem to think that they

have done enough if the latitude and longitude are given. But, in every case, at least

the time of day, the temperature of the horizon of capture, the kind of net and the depth

at which it was worked should be recorded. In eases below (pp. 48, 49) where I have

not been able to trace contemporary records of the temperature, I have supplied the

mean for the position and depth from Dr. Buchan’s ‘ Challenger’ Report on Oceanic

Circulation as the best approximation ; these are marked M.

* In practice, the nine hauls of the small-mouthed net with 180 meshes per linear inch have been found

impossible of fair comparison with the other hauls; this net caught practically nothing, while the ordinary nets

with 60 meshes were catching a good deal.

THE AMPHIPODA, 47

CYPHOCARIS ANONYX, Bocck.

Mr. Stebbing here treats his mécronyx as a synonym of the above species. The previous

records of the species thus enlarged are :—

1. Sta. 295 ; 38° 7’S., 94° 4/ W.; sounding 1500 fathoms, from the tow-net at the trawl.

‘Challenger ’ Temperature 35°°3.

2. Sta. 335 ; 32° 44/S., 13° 5’ W.; 1425 fathoms, from the dredge *. Temperature 37°.

¢ Hirondelle’ (3. Sta. 253; 47° 38/7 N., 22° 13’ W.; 710 fathoms, “filet bathypélagique & gouvernail ” +.

\ Temperature (mean) 42°.

4, 5, 6. Sta. 4-6 ; 52° N., 15° W.; open nets lowered to 1670, 1300, and 510 fathoms.

Lowest (mean) temperatures, 36°, 37°, 46°.

7. Greenland. Mean annual surface-temperature of Southern Greenland, 35° to 40°.

©Oceana’. . {

There can be little doubt that this is a cold-water form. Boeck gives no record of

depth with the Greenland specimen in the Copenhagen Museum, but before 1870 it is

not likely to have been captured from any considerable depth in a Greenland area.

JASSA PULCHELLA, Leach.

The confusion to which this species was reduced, though lately disentangled by

Mr. Stebbing {, yet makes it difficult to trace the records of its distribution. It appears

_ to range as a neritic form from Norway (but not into the Arctic Ocean) by England,

4 France, and Spain into the Mediterranean ) as far as the Bosphorus, occurring also at

Teneriffe and the Azores ||. But, so far as I am aware, it has not been taken as an

oceanic form previously to this cruise of the ‘Research’ (47° 5' N., 7° 45' W., being

roughly 2° 103’ from the nearest land); but, as Mr. Stebbing reminds me, it readily

~ attaches itself to floating objects, and may have put to sea unadvisedly in this manner.

Considering how much is known of northern Crustacea, it seems safe to put its minimum

about 44° or 45°, the mean annual of Trondhjem Fjord.

4 ScINA CRASSICORNIS (Fabricius).

_ This species has a wide horizontal distribution. It was taken at the surface near

173 fathoms and the surface ; but this is due probably rather to the enormous catching-

power of this net than to the organism having been captured at the lower zones of its

course. These, and a haul of the ‘ Pola’ ** at 273 fathoms with the Monaco closing-net

Me . *Chall. Rep. Summary of Results,’ ii. p. 1224.

+ So far as I can ascertain from M. Chevreux’s preface, this is the “ filet pélagique 4 rideau” of the Prince of

Monaco’s paper on gear in Cong. Internat. Zool. i. p. 133 (189), ordinarily known as the ** Monaco net.”

¢ T.R.R. Stebbing: Ann. & Mag. N. H. (7) iii. p. 287.

§ G. 0. Sars: ‘Crustacea of Norway,’ Amphipoda, p. 594.

|| E. Chevreux : ‘ Amphipodes de l’Hirondelle, p. 106.

{| J. Vosseler: ‘ Amphipoden der Plankton-Expedition,’ pp. 116-118.

** T. Garbowski: Denkschr. Akad. Wien, lxiii. Comm. Erforsch. dstl. Mittelmeeres (fiinfte Reihe), p. 113.

“a

48 DR. G. H. FOWLER—BISCAYAN PLANKTON:

in the comparatively warm water of the Mediterranean, seem to be the lowest strata to

which a net containing Scina crassicornis has been lowered, but it has yet to be shown

that it reaches these not very considerable depths in the Atlantic.

Speaking of the Scinidze as a whole, Dr. Garbowski says that they exhibit “ bathy-

metrische Indolenz und Eurythermie” ; and till closing-nets are more used we must be

content with such general statements. But it must be borne in mind that the ‘ Pola’

worked in the Mediterranean only, a “closed sea” where the decrease of temperature

with depth is very slight when compared with that in the open ocean ; and that at the

lowest depth with a closing-net from which Garbowski obtained crassicornis, viz.

273 fathoms, the mean temperature is about 56°. A species may be markedly eurybathic

in the Mediterranean without being correspondingly eurythermic.

At the same time some species of Scinidee, e. g. Clausii, are apparently eurythermic ;

but the family seems as a whole to dislike very cold water, since not a Scina was recorded

by the Norwegian North Atlantic Expedition. The single exception, the one outlier to

the North at present known, is Scina borealis.

ScINA BOREALIS (Sars).

This appears to me to be one of the most interesting finds. Its previous records are

most easily expressed in a table :—

Locality. Depth in fathoms. Net. Temperature. Authority.

Lofoten Islands. BOO een iets | lt s eee M. 39°

fe Crust. Norw. Amphip.

Trondhjem and Dredge or tow- 20

greet 1 iz : ° p. 20.

Christiania Fjords. ete ee { net near dredge. } i

Feroe Channel Norman, Ann. & Mag. N. H.

: 300 : irca 33° to 54° \ 4

TLMS. ‘Triton,’ } ee pen Chane io. (7) v. p. 135.

Feroe Channel, H.M.S. \ 465 to 335 Miecoplacien 31° to 33° baci Proc. Zool. Soc.

‘ Research,’ 1896, 1903, i. p. 128.

Bay of Biscay, } 524 to 0 Dee M. cirea 49° to? Bouvier, Ann. Univ. Lyon,

s.s. ‘ Caudan.’ Camp. de ‘ Caudan.’

3s. ‘ Fram,’ 80° N. 300 to 0 Open. eiroa 32° Norweg. North Polar Exped.,

Sars, Crust. p. 19.

Bay of Biscay, H.M.S. 1250 to 0 Open. 38° to 63°

‘ Research,’ 1900. \ 750 to 500 Mesoplankton. 48° to 49°

Tt seems to be most unlikely that it occurs at the surface or moderate depths in the

North Atlantic, as neither the ‘ Hirondelle,’ ‘ National,’ nor ‘ Buccaneer’ met with it. I

cannot but think that it will prove to be a purely cold-water form, seeking its optimum

temperature at considerable depths in low latitudes.

THE AMPHIPODA. 49

HYPERIOIDES LONGIPES, Chevreux.

The table of occurrences of this species (p. 53) shows conclusively that at the time

of our cruise, and in our area, the 100-fathom horizon was the centre of its vertical

distribution. It occurred in:

86 per cent. of the 22 hauls at 100 fathoms,

6c yo ~ ee eS

”

) 15 ” » 13 2 50 ”

| 8 5 95 12 # Om ates

! 0 ” » 25 ”» 0 ”

and in the two closing hauls 21 (150 to 100) and 21 p (150 to 50). It occurred in not

one of the 35 “ comparable”’ hauls which closed at various depths below the 100-fathom

line. The serial hauls 36g, h, 7, and & were open tow-nets, and may possibly have

captured it at any depth /ess than that to which they were lowered. It is not certainly

apparent from the table that the species rises particularly at night.

The captures by the ‘ Hirondelle’ seem to point to a greater depth, but they would

have carried more evidence had any one of them included more than a single specimen ;

they were as follows :—

Station. Position. Depth in fathoms. Temperature, ° F. jet.

169 44° 49'N., 9°16’ W. 269 M. circa 52° ¢ 4 ressort ” *.

253 46° 38' N., 22° 13' W. 710 M. 42°/3° “4 gouvernail” *,

256 48° 24' N., 20° 38' W. 1201 M. 38°/9° Fe re

258 47° 42' N., 19° 30' W. 426 M. 47°/8° 4 "3

_ The species described by Vosseler as Hyperia sibaginis? does reach the surface rarely ;

er in the Tocantins (mouth of River Para). Mr. Walker records it from the

seana’ collections as having been taken in open nets lowered to 150 and to

0 fathoms.

PARATHEMISTO OBLIVIA (Kroyer).

ing to the small size of the specimens, Mr. Stebbing expresses himself as not

certain of the identification. It is noticeable from the table (p. 51) that as it

> appears in any of the 22 hauls at 100 fathoms, these small specimens, unlike

perioides longipes just mentioned, probably do not live at that depth; in that case the

» specimens from 21m, 21”, and 210 were perhaps adopting a mesoplanktonic

; for from the evidence which I have previously adduced +, it seems likely

thypélagique ” of the Prince of Monaco,

t Proc. Zool. Soc. 1898, p. 583, & 1903, i. p. 126.

50 DR. G. H. FOWLER—BISCAYAN PLANKTON:

when adult; and the largest of these specimens was only 3°75 mm. The adult has

already been recorded* from an open deep net (409 to 0 fathoms) in the Bay of

Biscay. Unfortunately the small number of captures on our cruise does not materially

increase our knowledge on this point, but does extend the epiplanktonic distribution

of the young considerably southwards, Valentia being the most southerly point hitherto

recorded to my knowledge.

EUTHEMISTO COMPRESSA (Goés).

For the distribution of this form, long supposed to be subarctic, compare Proce. Zool.

Soc. 1903, i. p. 127, and Vosseler, ‘ Amphipoden der Plankton-Expedition,’ p. 86.

PRIMNO MACROPA, Guérin.

This seems to be a nearly cosmopolitan species, at any rate if the synonymy referred

to above by Mr. Stebbing be accepted.

BRACHYSCELUS MEDITERRANEUS (Claus).

This widely-distributed species was described by Claus from Naples, and recorded by

the ‘ Challenger’ at various localities in the North and South Atlantic, always at the

surface. By the ‘ Hirondelle,’ in addition to two surface-captures, it was taken with

the “filet & gouvernail” from 710 and 1201 fathoms, by the ‘Oceana’ in open nets

lowered to various depths.

Previous records of the remaining species are most easily placed in tabular form (p. 52),

The following table (p. 51) shows the occurrences of the various species of Amphipoda

expressed as serial numbers in the list of species. The first three hauls are with the

mesoplankton trawl, the remainder with tow-nets ; “‘non-comparable” hauls are marked

with a f.

1. Cyphocaris anonyx, Boeck. 13. Lanceola pacifica, Stebbing.

2. Huswrogenes dolichocarpus, sp. n. 14. Vibilia armata, Bovyallius.

3. Jassa pulchella, Leach. 15. Vibilia propinqua, Stebbing.

4. Archeoscina Bonnieri, sp. n. 16. Phronima sedentaria (Forskal).

5. Parascina Fowleri, sp. 1. 17. Hyperia luzoni, Stebbing.

6. Scina crassicornis (J.C. Fabricius). 18. Hyperioides longipes, Chevreux.

7. Scina edicarpus, Stebbing. 19. Parathemisto oblivia? (Kroyer).

8. Scina marginata (Bovallius). 20. Euthemisto compressa (Goés).

9. Seina Rattrayi, Stebbing. 21. Primno macropa, Guérin.

10. Scina lepisma (Chun). 22. Brachyscelus mediterraneus (Claus).

11. Scina borealis (Sais). 23. Brachyscelus, sp. indet.

12. Lanceola estiva, Stebbing.

* J. Bonnier: Ann. Univ. Lyon, Campagne de ‘ Caudan,’ p. 611.

THE AMPHIPODA.

Horizon. Haul. Species. Horizon. Haul. Species.

500—250 29 at 100—0 21h 18

1500—750 30 at 21 7

2000—1000 2012 22a 18

246 18

23 24d 18

24e 18

19 25d 18

30 9 18

19 30h 18, 21

32 d df, Wis, 210)

327 18

32 n, n' 18, 13

32 p 18

33 d 18, 23

19 345 13

3 34d Ife, alts}

19, 23 35 6 18

35 d 18

3, 19 30 f 16, 18

39 x 6

366 18

19 36 ¢ 18

150—0 36 f a

150—50 21p 18

19 150—100 21a 18, 19

200—0 2la

369 18

6, 19 200—100 216

2lo 19

26e

ath

35m

35 10

19 35 t |

19 250—0 36h 18

18 364 18

250—150 35.0

6 35 p 8

19 35s

300—0 36k 10, 18

15 300—200 2le

19 26f

21 B51

18 350—0 361 12

400—300 21k 1

i) 321 1

19 35 k 4

6 500—400 21m 19

6, 14, 21, 22 35h

18 35%

19, 21 750—500 22b

80k

19 B4e 11

34 f

1000—750 234

18, 19 27¢

19, 21 3d

9 32 f

18 82k

6 1250—1000 24a

27 b

3le

18 1500—1250 25 f

16, 18 307

2000—1500 25

266 5

SERIES.—ZOOLOGY, VOL. X. 9

Species.

Scina edicarpus,

Stebbing.

Scina marginata

(Bovallius).

Scina Rattrayi,

Stebbing.

Seina lepisma (Chun).

Lanceola cestiva,

Stebbing.

Lanceola pacifica,

Stebbing.

Tihilia armata,

Bovallins.

Vibilia propingua,

Stebbing.

Hyperia luzoni,

Stebbing.

38°

DR. G. H. FOWLER—BISCAYAN PLANKTON :

Locality.

HonlaiNes Loca WW.

Warm Atlantic.

47° 38' N., 22° 18' W.

Mediterranean.

1° S5ENE 2 Obes

47° 4'N., 19° 30’ W.

Various parts of

warmer Atlantic.

Between Teneriffe

and Grand Canary.

8° 37’ S., 34° 48! W.

1° 47' N., 24° 26' W.

35° 41'N., 157° 42’ E.

South and Tropical

Atlantic.

S. Equat. Atlantic.

N.E. Atlantic.

25° 30' N., 138° 0' E.

Warm Atlantic.

Homao WN. iis 47 Dy

10° 14’ N., 122° 54’ E.

2'W.

6’8., 88°

Warm Atlantic.

Depth in fathoms.

“ From a depth of

100 fathoms.”

109 or 218 to 0

710

Various.

“ After 9.0 p.m.

from a depth of

360 fathoms.”

426

218 to 0

{ 1670 to 0

874 to ?0

675

1850

2300

273 or 218 to 0

790 to O

Surface.

273 or 218 to 0

Surface.

218 or 109 to 0,

once at surface.

Net.

Open.

Vertical & trawl.

? Monaco closing.

ee neee

? Monaco closing.

Open vertical.

Open serial.

? Closing-net.

Trawl.

Open vertical.

Open serial.

Open.

Open vertical,

Open.

Vertical and

Plankton nets.

Il. THE CLADOCERA.

Temperature, ° F.

M. 56° to 82°

M. 60° to 79°

circa 42° to 82°

circa 47°/8°

M. 47° to 80°

Various.

M. 44° to ?

cirea 38°

36°

35°

Die te.fe eum

M. 44° to 78°

M. 40° to 55°

78°°5

M. 47° to 82°

76°5

circa 80°

59°8

M. 49° to 79°

EvapNE NorpMANNI, Lovén.

Authority or Ship.

‘ National.’

‘ Hirondelle,’ Sta. 253.

Various.

‘ Buccaneer.’

‘ Hirondelle,’ Sta. 258.

‘ National,’

‘Oceana.’

Chun, SB. Akad. Berlin,

1889, p. 533.

‘Challenger,’ Sta. 120.

‘ Challenger,’ Sta. 106.

‘ Challenger,’ Sta. 241.

Bovallius, Svenska Vet.-

Ak. Hdlgr. xxi. p. 69.

‘ National.’

‘ Oceana.’

‘ Challenger.’

‘ National.’

‘ Challenger,’ Sta. 206-7.

‘Challenger,’ Sta. 209.

‘ Challenger,’ Sta, 296.

‘ National.’

There can be little doubt from the table (p. 54) that this is a truly epiplanktonic

species.

It oceurred plentifully in 42 per cent. of the hauls between 100 and 0 fathoms.

Single specimens also occurred in only two out of the possible 86 hauls which closed

before or at the 100 fathoms (34:e, 750 to 500 fm.; 31d, 1000 to 750 fm.).

THE AMPHIPODA.

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DR. G. H. FOWLER—BISCAYAN PLANKTON.

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BISCAY AN PigANK TON.

Part I1I.—THE CHATOGNATHA.

By G. Herzpert Fowier, B.A., Ph.D., F.LS., F.ZS.

(Plates 4-7.)

Read 2nd June, 1904.

Contents.

Page | Page

The Systematic Determination of Chetognatha .... 55 Sagitte spp. indet. of hexapterine type ...... 7

Examination of the * Research ’ Specimens ........ 58 Krohnia hamata, Moebiust....-..+- soe 74

Sagitta serratodentata, Krohn .............. 58 Krohnia hamata, Moebius, var...........+++- 77

Ont UrCatG, SUCIMNAUBS |)... eves cee ss + 63 eGo eaaet GAGS. (CNERIS. Cocdoepcaoenoernede 7

Sagitta macrocephala, sp. 0. ..-...+. 0.24.00 65 General Remarks on the Vertical Distribution .... 79

STIG CALSOAS Site Ge ae Bence cod Dele 67 | Summary of the Observed Distribution .......... 82

Sagitta bipunctata, Quoy et Gaimard ........ 69 | Table of the Occurrence of the commoner Forms.... 84

ISEELLGACLECIPTEIS41SP-\ Te ..c lela wiv elect vie «ee aie 21s 70 | Appendix: Chetognatha from the Falkland Islands. 85

Nr TULCAS PemlNOe tiey Con UlWete-isyelspcleha crti + ele)olls6 ov oie PAMMIIM Utrevee Gime oars coc CORREA DEES Comebrrnaeo ne 85

Sagitta ? planctonis, Steinhaus ............-- ciel | xplanation of thepblatess. <<. cj. o-we asee saieeloe 86

ON THE SYSTEMATIC DETERMINATION OF CHETOGNATHA.

NS - — . 2 2

BISCAYAN PLANKTON: Parr III. CHETOGNATHA.

(Trans. Liv. Soc., Ser. 2, Zoon. x. 55-87 .)

Temporary correction-slip.

Page Line

57 6 Add: “In the measurements of ‘ total length’ and of ‘ tail-segment,’

the tail-fin has been included, greater accuracy with less damage

to the specimen being attained thereby.”

58 5 from bottom. For “ body” read “ trunk.”

63 7 a* » ”

67 10 ad 39 > ”

69 3 Add: “A slight short thickening of epidermis behind the head,

scarcely enough developed to be termed a collarette.”’ =

69 . For “body ” read “ trunk.”

78 5 from bottom. FS Pe 3

78 2 from bottom. For “usually ” read “ unusually.”

pS THIS SWeEpIng stavemeny may yo-s01—ve-awypueew—yuoveerwwvevens — ene -~e ee pep ---y

measurements showing the tail-segment of a species to be 24 per cent., or nearly a quarter, of the total leaner but

e% draws it 31 per cent., or nearly a third. Another writer says that “ the posterior fins touch the vesiculee seminales,”

yet draws them far apart; in another species he describes the tail-segment as a fourth of the whole length, and

* draws it as 35 per cent., or more than a third. When one finds such inaccuracies in easily measurable matters,

b ~ absolutely no reliance can be placed on the figure as a whole.

-_-—« SECOND SERIES.— ZOOLOGY, VOL. X. 10

BISCAYAN PLANICTON.

Part II].—THE CHATOGNATHA.

By G. HeRBerT Fowuer, B.A., Ph.D., PLS, B.ZS.

(Plates 4-7.)

Read 2nd June, 1904.

Contents.

Page Page

The Systematic Determination of Chetognatha .... 55 | Sagitte spp. indet. of hexapterine type ...... 73

Examination of the * Research * Specimens ........ 58 | Krohnia hamata, Moebius.........+..20++0% 74

Sagiita serratodentata, Krohn .............. 58 Krohnia hamata, Moebius, var...........++-+ Gb

agutia furcata, Stemhaus........0022..+-.. 63 Krrohinia subtitles; | Cr assic jc) isi) - «ieee ielei-ie isle 78

Sagitta macrocephala, sp. 0... +... 00 eevee 65 General Remarks on the Vertical Distribution .... 7

STO FAR CS 1 Gos SO ee Hoe Cree 67 Summary of the Observed Distribution .......... 82

Sagitta bipunctata, Quoy et Gaimard ........ 69 | Table of the Occurrence of the commoner Forms.... 84

PSNI RTICENCLECUDTENS (SPs Ts .,5, cls bie. sieiels sos cies oe ss 70 | Appendix: Chetognatha from the Falkland Islands. 85

SEGULACASPHEINGEL AT YUVialeys ciel ye cee sis. oe ss 7 Patter ame vers: <,0-sceheeeetere eae teteyetsne\ei v tates ous sy saterayeecyae 85

Sagitta ? planctonis, Steinhaus .............. CL | Bxplanptionvofthepelabes crs eee ais lels1elo eis oiertehe oto! ie 86

ON THE SYSTEMATIC DETERMINATION OF CHE TOGNATHA.

CONSIDERING the comparatively small number of species, few animals can be more

troublesome to identify than a large collection of Cheetognatha. This results not only

from the inadequate diagnoses by many of the earlier describers, but also from the

scarcity and variability of the external diagnostic characters, the considerable differences

in the proportions to one another of the various parts (produced in the less firm species

by varying degrees of expansion and contraction), and the difficulties of satisfactory

preservation.

Taking these points in a little more detail—Oscar Hertwig reduced to order such

species as came under his notice, but unfortunately these were not numerous. Had all

later observers given equally careful descriptions, our task to-day would have been

easier; but, as if is, cursory descriptions of a few external features, taken apparently, in

many cases, from only one or two specimens, are the rule in the literature of the

subject. Almost more trouble has been caused by inadequate drawings *; considering

a how closely alike at first sight are even such undoubtedly “ good”’ species as heraptera

+ and enflata, no freehand drawing of the outline of a Sagitta can be trusted, because a

quite small error in the proportions of head, body, tail, and fins may easily give the

misleading outline of another species. Every reporter on a collection of Cheetognatha,

who desires to help in placing the genera and species on a proper footing, should give an

* Perhaps this sweeping statement may be held to require justification. Among recent papers, one author gives

measurements showing the tail-segment of a species to be 2+ per cent., or nearly a quarter, of the total length, but

draws it 31 per cent., or nearly a third. Another writer says that ‘ the posterior fins touch the vesicule seminales,”

yet draws them far apart; in another species he describes the tail-segment as a fourth of the whole length, and

draws it as 35 per cent., or more than a third. When one finds such inaccuracies in easily measurable matters,

( absolutely no reliance can be placed on the figure as a whole.

SECOND SERIES.—ZOOLOGY, VOL. X.

56 DR. G. H. FOWLER—BISCAYAN PLANKTON :

outline drawing by camera lucida of a typical specimen of every species, however well

known, wherever possible.

As regards the variability of diagnostic characters, it seems to be very desirable that

for every species in every collection (however common) a table should be furnished

showing at least the proportion of tail to total length, with the numbers of jaws and

teeth at different lengths, until such time as we shall have gained some idea of the

variability within the limits of each species. More measurements would be desirable,

but are often impossible owing to the imperfect condition of the specimens.

As regards preservation, the material from the ‘Research’ and from the ‘ Siboga’

Expeditions leads me to believe that the best method is to preserve each specimen

separately in formalin, at first weak, then in a stronger solution (5-7 per cent.). Neither

sublimate, picric acid, osmic acid, nor spirit (alone or in combination with the foregoing)

gives such good results *.

Some characters which have been used in diagnosis seem to require clearing away.

The projection, size, and shape of the vesiculze seminales appear to depend entirely upon

the sexual condition of the individual at the moment of capture. The size of the ova

seems to me also to be valueless, since one cannot always tell whether they are ripe or

not. The extension forwards of the ovaries has more significance, but too much stress

must not be laid upon it; for example, the mature ovaries reach to the neck in robusta,

never (so far as I have seen) more than halfway to it in enflata, but a developed ovary

of enflata and a half-grown ovary of vobusta are of the same length and have ova of

nearly the same size. Drawings and measurements of the head are diagnostically

almost valueless—its shape, proportious, and apparent size alter so enormously

according to the condition at death, with the extension forwards, outwards, or inwards

of the jaws, with the retrusion into the prepuce, &c.

The presence or absence of two diverticula on the alimentary canal in the neck has

been used diagnostically by recent writers: so far as my experience goes, these depend

on the extent of protrusion or retrusion of the head; at any rate within the limits of

the same species I have found some specimens with, and some without, these diverticula.

The colour of the body does not appear to be diagnostic: specimens from deep water

are often of a salmon-pink; but in the same hauls some specimens of hamata and

macrocephala were pink, others colourless.

If specimens were always perfectly preserved, the fins would be a good guide to

species, and in many cases are of some value when present; but they are so often

shrunken, torn, or rubbed away as to be of no help. The form of the corona ciliata is

useful, when it is retained on a specimen (by no means always the case) f.

* So far as Cheetognatha were concerned, I committed a great error in making the epiplankton hauls too long

(generally one hour: half an hour would have been preferable). Specimens which are caught early in the haul

become compressed against the sides of the net, and the prolonged pressure flattens and otherwise damages them

considerably (cf. the account of S. furcata, p. 64). More numerous hauls of shorter duration would have yielded

better specimens and would ultimately have saved time, at a slightly greater expenditure on bottles, cases, &e.

_ + In order to see this, and to make outline camera drawings of the whole animal, I have found nothing better

‘than a 1 per cent. solution of methyl blue, used for about one minute. The colour soon fades, and leaves the

specimen uninjured for museum purposes. In drawing, I have found the Giltsch-Zeiss support, used with an Abbé

camera, invaluable. ;

THE CHATOGNATHA. 5

It may, then, be asked, what is left by which to distinguish the species of Cheetognatha ?

The general outline of the body counts for something; that is to say, the proportion of

head to body, the position of the thickest part of the bea. the ratio between the lengths

of the postanal region and the trunk. Of these only the last one can, as a rule, be

safely expressed in measurements, as the proportions of head and body vary so much

with the extent of the death-contraction. Other fairly fixed characters are the presence

or absence of a constriction between head and body to form a “neck”; a lateral

expansion of the ectoderm at this point * ; a sudden diminution of the body-diameter at

the anus as contrasted with a gradual tapering, or a marked constriction at the

septum +.

The consistency of the body is of some value: those species with comparatively large

longitudinal muscles and small muscle-free lateral fields (e. g., bipunctata) have a firmer

consistency, and in formalin a more opaque appearance, than species with comparatively

poor musculature and large lateral fields, such as hevaptera; these seem tlabby and

transparent in formalin, and often have a wrinkled appeamance, if not very carefully

preserved when alive.

| As regards the lateral fins, if well preserved, a comparison of their width with that of

_ the body, and a comparison of the widths and lengths of the two pairs, are more safely

expressed by camera drawings than by measurements; their extension forwards as

tested by the ventral ganglion, backwards as tested by the vesicule seminales, centrally

as regards the anal septum, are of great value. The tail-fin is less instructive ; its

_ extension forwards as regards the vesiculze seminales is useful, but its outline is very

readily damaged, and a truncate fin easily splits into an apparently bilobed one, or wears

| into an ensiform shape. Too much stress must not be laid, except in perfectly

preserved material, on the triangular or elliptical outline of the posterior fins: it is

“quite easy to find specimens (e. g., of furcata) with an almost triangular fin on one side

which had been rubbed into an ellipse on the other.

~The most stable parts of a Cheetognath are formed by the cephalic armature—the

jaws (cirrhi, uncini) and teeth {. These are often the only characters by which to

identify a badly preserved specimen, but they must be used with care, since, as I shall

how later in dealing with the various species captured, they are liable to considerable

aviation. Still, allowing a considerable latitude for these variations, their mere

mbers afford a fairly accurate criterion when taken in conjunction with the characters

ready cited. If to these be added a detailed study of the jaw-structure, such as

Dr. Krumbach § has recently worked out for several species, the observer may feel

* For this, which has been termed a “ neck-fin,” [ have used the name “ collarette.’

+ Dr. Krumbach writes that he has worked out the form of the tail-segment as a diagnostic character for

Mediterranean species.

£ The counting of these is often troublesome. I use two short slips of glass cut from a slide, lay one across the

dorsal surface of the specimen just behind the head, and then, bending the head upwards and backwards with a

needle, prevent it from falling forwards again by pushing the second glass slip up against it; and drop a cover-glass

on the whole. ‘This enables one to study the armature from the anterior end, and generally to count the teeth and

_ jaws readily.

} § Th. Krumbach: “ Ueber die Greifhaken der Chiitognathen,” Zool. Jahrb. (Abth. Syst. u.s. w.) xviii. 579

(1908),

10*

58 DR. G. H. FOWLER—BISCAYAN PLANKTON :

himself on safe ground. As a secondary character, I find the form of the vestibular

ridge, which lies just in front of the posterior teeth, to be of assistance. In many

cases below, the anterior and posterior teeth have been figured, but I doubt whether

such drawings have much value; the teeth look so different when viewed at different

angles.

EXAMINATION OF THE ‘ RESEARCH’ SPECIMENS.

The first hauls examined were dealt with very carefully; the dimensions of every

specimen taken, and the jaws and teeth counted, until every common species had the

look of a familiar friend. After that, the epiplankton hauls were sorted, chiefly by a

dissection-lens, measurement and counting being done only in cases of doubt, or as an

occasional check on sorting by eye. Of the mesoplankton hauls, on the other hand,

every specimen (except a few young zetesios) was measured and counted and identified

with care. When the whole collection had been thus sorted into species, every specimen

was re-examined; and as there were over 2100 specimens, the task has not been

light.

It is therefore possible, though not likely, that a few “hexaptera?” have been mistakenly

assigned to furcata. Mistakes are especially likely to occur with very young specimens

(one species excepted), and they have therefore not been recorded when in the least

doubtful: small specimens are often impossible of determination in the present state of

our knowledge, because the numbers of jaws and teeth are then small, and the

proportion of tail to trunk is generally higher than in older specimens; even the

character of the jaws alters with age in some species. The one exception referred to

above is fortunately the interesting hamata, the hooked jaws of which are recognizable

even at 55 mm. total length; in young servatodentata the younger (dorsal) jaws alone

are hooked, and more slightly so than in hamata.

SAGITTA SERRATODENTATA, Krohn. (PI. 4. figs. 1-6.)

Characters.—Head small; body slender, pin-like like dipunctata, thickest about the

middle of its length, tapering gradually forwards and backwards ; a marked neck, but

no collarette; body firm, retaining its shape. Longitudinal muscles broad, but thin ;

lateral fields rather narrow ; no marked constriction at the septum.

Anterior fin long, extending to ventral ganglion, widest near its posterior end.

Distance separating the anterior and posterior fins very short. Posterior fin long,

longer and wider than the anterior, extending to (or very nearly to) the vesiculz

seminales ; about as much on body as on tail; widest point about midway between

septum and vesiculz seminales. ‘Tail-fin truncate.

Ventral ganglion of medium size, prominent. Corona ciliata long, sinuous, extending

from between the eyes to about halfway to the ventral ganglion. Jaws strongly

curved; the younger (dorsal) jaws serrated and slightly hooked at the tip *. Teeth of ~

* For a detailed description, see Krumbach, Zool. Jahrb. Syst. xviii, (1903) 579.

THE CHATOGNATHA. 59

both rows comparatively short and triangular. Vestibular ridge with rounded

prominences fewer than the teeth, ridge about the same length as the posterior row.

At 10:

‘

UL padanoo0 sotoads sty} sSMOYyLT

; | Length in mm. eee of | Jaws

15 26 627

14 25-28 67

13 22-34 6-8

12 a550) | 7

ul 27 | 8

10 30-35 i

9 27-33 6

8 25-31 | 6-7

7 28-35 | 6-7

6 30 | 6-7

5 30-36 | 6

——_ -+,- — ES + Yh

It is fairly obvious from the percentages of

that the expectation of meeting with serratodentata increases with the depth down to

_* This table is to be read asa sentence from left to right.

+ Throughout the discussion of distributions, the “average specimens ” are averaged over all hauls at the depth

mentioned ; not merely over those in which the species occurred. See also note T on next page.

| |

Anterior Posterior

| teeth. teeth.

eo ee = —

| 6 12

| 5-6 10-11

6-7 8-12

4-7 8-13

6 9

| 4-6 7-10

| 4 5-6

3-4 6

ee? 34 2-6

3-4 5-6

2-3 3-4

General Distribution The general table of Chzetognath occurrences and the table

average specimens following show that this form is essentially epiplanktonic.

Signe

3 \ fo}

ple 4 s

Do 40 de

a g | oO

et 96. | g

= } @

=: 3°4, @,

BS ct 4 5

= 5:3 g

| an

LOM |

= g

8 POU; )

— |

¥ oO | &

= —

= tps |p css

> 5 } =

10 / +

hauls in which the species occurred

60 DR. G. H. FOWLER—BISCAYAN -PLANKTON:

100 fathoms. The average expectation of specimens would seem to be greatest at the

surface and 50 fathoms, time of day and other variants being neglected.

From the facts cited above it is obvious that the distribution of this species is

between the surface and 100 fathoms, possibly but improbably, a little deeper.

Reaction to Time of Day, Light, Rain, Sc.

The hauls with open nets in the epiplankton were arranged, so far as circumstances

allowed, to test the alleged nocturnal rise and diurnal fall of the fauna of the upper

strata, and the effect on it of varying physical conditions. I have endeavoured—with

great elaboration, but very little success—to use servatodentata as a test-case, since it

was fairly plentiful at the higher levels.

In the first place, when arranged on the time-depth tables *, the occurrences show no

indication whatever of a nocturnal rise and diurnal fall.

In the second place, with regard to the reaction of this species to light, I adopted

Mr. E. W. L. Holt’s suggestion of a photographer’s actinometer (¢f. supra, p. 6).

The numbers of specimens captured t were arranged by light-intensity at the various

depths down to 100 fathoms into six groups, according as the sensitive paper of the

actinometer reached the standard tint at 2”, 3” to 6", 7” to 10", 11” to dusk or dawn,

or as the night was dark or brightly moonlit. The only thing that seemed definitely

to come out of this attempt was the negative proposition that ser7atodentata has no

special affection for moonlight, since six hauls in bright moonlight produced in all

but five specimens. On the other hand, the largest numbers of specimens taken at the

surface occurred in a 2” light (48 specimens) and between 11” and dusk (51 specimens),

so that the actual light-intensity of the moment in daylight does not seem materially

to affect its presence at the surface.

Now, although the light-intensity of the moment ¢z daytime does not seem to affect

the distribution of servratodentata, nevertheless it would seem that there exists an

oscillation of this species, but it is the exact contrary of that generally alleged to affect

the epiplankton. Dividing the upper hauls into three groups:—(1) daylight, 3 a.m. to

7 p.M.; (2) night, 7 p.m. to 3 a.m.; (3) hauls taken during or after rain, irrespective of

the time of day, and not reckoned under (1) and (2): then we have the following

table, showing the average, the maximum, and the minimum number of specimens

captured :—

* Reproduced on p, 62: the occurrences of the species are marked in heavy type. The construction is described

on p. 7 (supra).

7 In these calculations, nine surface-hauls made with a net of 180 meshes per inch linear have been omitted,

as it was obvious from a comparison with other nets of wider mesh out at the same time that its small mouth and

small filtering area made it useless for catching Sagitta, The numbers actually caught have been treated with a_

time-factor to bring them to the standard one-hour haul, which was the usual period: for example, the numbers

taken in a half-hour haul have been multiplied by 2, those taken in a two-hour haul divided by 2, &c. Single

specimens, however, have not been divided.

THE CHATOGNATHA. 61

= | | Specimens.

Se nee ee

| vo | Average *. | Maximum. | Minimum.

. ry |. va a rr

4 0 Ca Dz |; Bee SS Si —— 2

4 s\| N. | 0-6 2 0

| 25 5 Dz 4:6 17 | 0

| 4 N a | af | 0

| 50 7 D. 9-8 28 | 0

3 N 6 | 2 0

75 - | Dz 40 | 6 i

| | 6 N ly | 6 0

400 _| that Dz 5-0 20 0

| 9 N 2-6 6 | 1

| ay

| joes SS

Ore 2 R. 0-5 l 0

25 | 3 R. 6-6 8 | 6

50 3 R. 18-3 | a RT at”

75 | if | R. 13:0 | 13 13

100 | 2 R. 19-0 28 | 10

The observations are by no means so numerous as one could wish, but on a

comparison with the average catch per haul already given, it will be admitted that this

table appears to bring out clearly two points :—Firstly, that the species seeks the

surface in daylight hours and shuns it at night; secondly, that during or after rain it

descends, being caught in the largest numbers between 50 and 100 fathoms. The two

rain-hauls at the surface were in the bright hours of daylight, when the average eatch is

22:1 specimens.

The average daylight catches at all depths except the surface are very close to the

averages taken over all hauls, whereas the average night catches are well below those

g eneral averages. I cannot account for this, except on the assumption that the species

‘shoals at the surface by day and scatters below by night. Although I never worked

below 100 fathoms at night, I do not believe that this species sinks below that horizon

inder any conditions of life, otherwise I should almost certainly have taken, at any rate,

sccasional specimens in the daylight of early mornitg or late evening in the closing-net.

* Averaged over all hauls, whether the species was captured or not.

FOWLER—BISCAYAN PLANKTON:

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= | Sill se | Bah eee eG) ee ee Ul. pos oe es ae SVS

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“a alk S| = =S eat ee Eas Se ee pa

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| | | | r|

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SAGITTA SERRATODENTATA, Krohn.

THE CHATOGNATHA. 63

Sacirra FuRcATA, Steinhaus*. (PI. 4, figs. 7-15.)

Characters.—Head comparatively small; body thick; neck not well marked in well-

preserved specimens; no collarette. Body nearly equally thick throughout the middle

third, tapering gradually towards the head, very rapidly to the tail; generally a marked

constriction at the septum. Longitudinal muscles broad but thin; lateral fields large;

the body is therefore transparent and flabby, easily compressed in the tow-net.

Posterior fin oval (elliptical), never quite triangular, about two-thirds on the body,

one-third on the tail; its widest part well in front of the septum; it ends at some

distance from the yesiculze seminales, but extends anteriorly nearly to the anterior fin.

Anterior fin widest posteriorly, but not so wide as the posterior fin; it extends nearly to

the ventral ganglion. ‘Tail-fin rounded and (? always) bilobed.

Ventral ganglion small. Corona ciliata resembling that of hexaptera, but almost

entirely on the head, just reaching the neck.

Jaws strong and markedly curved. Teeth long, strong, sharp.

ie | ae.) Inet), Pe

coal

35 | if 6-8 5-7 11-12

33 17-18 7-8 7-8 9-10

31 18-20 8-9 6-7 9-11

28 18-21 [3 6 gett

26 19-21 8-9 6 10 |

23 19 8-9 5 8-9

21 18-21 7-9 5 7-8

19 | 18-21 7-8 5-6 6-8

17 17-23 8-9 4-5 7-8

15 20-23 8-9 4 6

13 17-23 8-9 4-5 5-7

12 | 24-25 | 8 3 5-6

These characters do not in every respect agree with those given by Steinhaus, notably

-as regards the fins. But from his mention of the ‘“ eigenthiimliche Runzelung der

Epidermis,” I gather that his specimens, like the majority of mine, had suffered severely

in the tow-net. As I was in some doubt as to the identity of my specimens with

reata, Dr. Krumbach, with some of Steinhaus’s specimens before him, was kind

* O. Steinhaus: ‘Die Verbreitung der Chetognathen im siidatlantischen und indischen Ozean,’

SECOND SERIES.—ZOOLOGY, VOL. X. 11

64 DR. G. H. FOWLER—BISCAYAN PLANKTON:

enough to inform me that they are specifically identical, even when tested by his new

criterion of the character of the tips of the jaws.

No species, to my knowledge, aiters more from damage in the tow-net and from faulty

preservation than this. In transparent and well-preserved specimens (fig. 7) the lateral

fields may shrink inwards so as nearly to carry the anterior fins out of sight; such

specimens are slightly flattened laterally. But in specimens caught early in the haul,

which were crushed by pressure of the water against the net and were dead before

preservation, notably in such specimens when preserved with picric acid, the trunk, or

the tail, or more often the whole body, has a corrugated appearance, and the epidermis

stands out laterally in a broad selvage, due partly to mechanical dorso-ventral com-

pression, partly, I think, to an actual loosening of the epidermis from the subjacent

tissue. This compression often makes the lateral fins appear much wider than they

really are, and sometimes even produces such a bridge between the anterior and posterior

fins as is attributed to Krohn’s species /yra* (fig. 9).

The lateral shrinkage or dorso-ventral compression made the identification so trouble-

some that, for the benefit of future workers, I have drawn four states of furcata, of

which I take fig. 8 to be the normal.

Distribution.—The general table of Cheetognaths and the figures immediately to be

given clearly indicate that this is an epiplanktonic species. The following table is an

analysis ¢ of the captures with open nets :—

Ate JOue Sime! 18 f

25 16 z& on ee

Se H aa | og

50 =, G4 Ae i A

75 E 100 | = 168 =

100 = 100 | 26:9 E

= ° ) : A

150 : 1 (e 30 3

200 = yk, ie 15 :

ia) =) >

250 = 2 | & 2-0 :

B | = = ad

350 1 Fy) 405 =

It occurred also in the closing-nets :—

150-50 fathoms, average specimens 13-0 ;

200-100 fathoms, average specimens 1°4;

but was not captured below the last zone t. From the above facts it is fairly apparent

that the species is distributed from the surface to 100 fathoms, with a maximum distri-

bution between 75 and 100 fathoms, a few specimens living between 200 and 100 fathoms.

* It is quite possible that the name /yra was given to some other species compressed in this fashion: if one

may judge from the general description and from the number of teeth and jaws, Krohn very likely had furcata

before him.

+ See note, p. 60.

+ Unless the specimens mentioned under lil. (p. 74) are really furcata.

THE CHETOGNATHA. 65

The occurrences at 0 and 25 fathoms were so few that no indication of any reaction

to time of day, light, or rain could be expected, even if such reaction existed. At

50 fathoms and down to 100 the specimens are so closely massed that we may regard

the captures at 25 and 0 as stragglers from the main body, just as those between 200 and

100 fathoms.

SAGITTA MACROCEPHALA, sp. n. (PI. 5. figs. 16-21.)

This species, coming only from considerable depths, presented but few specimens in

sufliciently good condition for accurate description. The following points, however,

will serve for diagnosis until better specimens are recorded by other observers.

Characters.—Head very large, forming when fully expanded a truncated triangle.

Neck narrow and without a ‘‘collarette.” Body slender, firm, but much thicker in the

middle than anteriorly ; lateral fields not large. Tail-segment about one-third or more

of the total length ; tip of tail generally bluntly conical. —

Anterior fins small and (?) rounded; posterior fins larger, rounded rather than

triangular, about equally divided between trunk and tail; tail-fin often pointed

posteriorly.

Jaws curved throughout their whole length, sharply so in the distal fourth. Teeth

very dark in colour, borne on an unusually stout bar. Teeth of the anterior row long

and slender, slightly curved inwards to the middle line, their bases touching, but in

complete expansion of the head they project radially outwards as a half-cirelet. Teeth

of the posterior row very numerous, closely set, long, and slender; in complete expansion

of the head they form a curve which goes completely from the dorsal to the ventral

surface, so that the dorsalmost point outwards, the ventralmost inwards.

Corona ciliata not observed. Vestibular ridge covered with a thick cuticle; it extends

externally for the whole length of the row of posterior teeth, internally somewhat

further, and carries irregular prominences fewer in number than the teeth.

Body sometimes salmon-pink, sometimes colourless. As the generative organs were

quite rudimentary in even the largest specimens, it is probable that only imimature

specimens were captured.

The great size of the head and the large number of teeth, compared with the size of the

body, mark this species off from all others hitherto recorded.

‘The following table* covers all measurable specimens captured; where the per-

Distribution.—Vhe vertical distribution of this species is conspicuously shown in the

able p. 84, and the diagram Pl. 7. It occurred in 63 per cent. of the 19 hauls which

closed at or beiow 400 fathoms; the only other certain captures were in deep hauls open

rom 1250 fathoms to the surface (27.4, 27a’). Six very small specimens from 82 J,

35 k, and 36 1 may be larvie of this species (macrocephala). It failed entirely in the

* The six specimens below the transverse line in the table include all the specimens from 32 1, 35,36 1—that is,

al the shallower occurrences. I think that they are larval macrocephala, but’ they are very small and the number

of posterior teeth drops rather suddenly. They are included in the curve macrocephala on Pl. 7.

DR. G. H. FOWLER-—-BISCAYAN PLANKTON;

18-0 28 iT 8-9 27

18-0 33 10-11 57 25-29

17-0 32 9 5-6 32

| 16:5 33 10 8 27-28

| 16-0 ‘a u 8 31

155 32 11 8 ” 33

15-0 36 iL fi 26-27

15-0 33 11-12 7 23004 ae

15-0 338 it 8 29-32

13-0 x 12 8 25

13-0 4 10-11 9 27-30

13-0 34 ul 7-9 23-24

12-0 ¥ 9-11 7-10 28-29 |

12-0 y 10 8 27

12-0 33 9-10 7 21

12-0 37 10 7 21

115 30 11-12 9 21-28 |

11-0 31 9 7 21

11-0 36 10 6 20

10°5 38 rfl 9 27 |

10°5 33 7 5 21

10-0 x | if 8 21-22

10-0 35 10-11 9 29-93

10-0 35 10-11 6 17-20

10-0 40 ul 6 18-20

10-0 33 12 7 22-93

9-0 oa Bl 5-6 14-16

9-0 33 | 9 10 20

9-0) 33 nf 6 19

9-0 38 10 6 17-18

9-0 33 1 7 19

8-0 43 9-10 6 15

7-0 10 5 12-13

7-0 35 9-11 5-6 14-15

7-0 10-11 3 6-7 :

65 38 10 7 5-7

| 6-0 41 9-10 4-5 1011

5-0 9 3 5

50 ie 10 4 7-8

5-0 40 1 4 8

THE CHARTOGNATHA. 67

15 hauls which closed between 300 and 50 fathoms, and in every haul with an open net

in which the greatest depth touched was less than 850 fathoms. 8. macrocephala was

therefore undoubtedly mesoplanktonic.

SAGITTA ZETESIOS, sp. n. (PI. 5. figs. 22-27.)

Characters.—-Head proportionately of medium size, larger than the body immediately

behind it, thus exhibiting a marked neck. Body fairly stout (stouter than bipunctata),

tapering from the middle gradually towards each end ; a collarette present; lateral fields

rather narrow, longitudinal muscles well developed; tail 25 to 33 per cent. of the total

length.

Posterior fin triangular, slightly more on the body than on the tail, its widest part at

or slightly in front of the septum, not extending backwards to the vesiculee seminales.

Anterior fin well separated from the posterior, longer and narrower than the posterior,

wider behind than in front, not quite or only just reaching the hinder end of the ventral

ganglion. ‘Tail-fin truncate.

Jaws very slender and strongly curved.

Teeth very long and slender, light-coloured (unlike macrocephala); the anterior teeth

increasing in size ventrally ; the posterior teeth at first increasing in length inwards,

then decreasing again in the few innermost.

Vestibular ridge well developed, but covered by a thin cuticle only, very slightly

mammillated by numerous small and irregular prominences, not extending for the

whole length of the row of posterior teeth.

Corona ciliata not observed.

This is a fairly well-marked species. The large numbers of posterior teetii are enough

to separate it from all but servratodentata, bipunctata, Bedoti, hispida, and elegans.

From serratodentata the absence of serration on the jaws is enough to distinguish it.

As compared with dipunctata, the head is larger, the body stouter, the lateral fins

wider, the teeth very much longer. Bedofi (Béraneck), of which I have specimens

from the ‘Siboga’ Expedition, has a much slenderer outline, and zefesios may be

distinguished readily by the larger number of jaws and smaller numbers of anterior

and posterior teeth in specimens of the same size. §. elegans (Verrill) has been

insufficiently described and figured, so that it is not easy to point to salient characters

for differentiation ; but at least the proportion of the tail-segment to the total length and

the number of jaws are easily checked. 8. hispida (Conant) has a quite different form:

the absence of a neck, the length and shape of the posterior fins, and the slender body

all mark it off from zetesios, though the numbers of jaws and teeth are almost identical.

The following table has been summarized from 388 specimens. The smallest specimen,

8 mm. long, is possibly referable to some other species.

The specimen of 32 mm., which is at the head of the table, is represented in fig. 23.

I have no doubt that it really belongs to this species, but that some curious action of

he preserving-Aluid has swelled out the epidermis in front of the anterior fin in a way

Which is common in my specimens of furcata and some other species. This was the

only specimen in which the vesiculze seminales projected noticeably. The vestibular

68 DR. G. H. FOWLER-—BISCAYAN PLANKTON:

Tenet Gham. Tail as p.c. of ee Anterior Posterior

2 length. teeth. teeth.

is wo icine TS | ee A if aH

| 32 25 8 8 W517)

21 33 8 9 15-18

20 25-28 8-10 7-9 17-19

19 26-28 8 7-8 15-18

| 18 OE 9 6 16

| 7 29 9 9 18

16 26 9 6-7 15 |

15 30 8 6-7 13-14

| 13 26-30 8-10 57 11-14

12 25-29 8-9 5-6 11-14

11 27-31 8-9 5-6 se

10 | 25-33 9 4-6 9-12

| 9 27-338 8-9 4-6 8-12

8 25 8 + 5-6

ridge was slightly more mammillated than in other specimens, in all other respects it

agreed with the characters of the species as given above.

The vertical distribution of zetesios agrees in its general features with that of hamata ;

and as both the occasions of capture and the specimens were Jess numerous in this than

in the latter case, it is fortunate that they thus receive corroboration. It failed at all

depths less than 100 fathoms, and occurred at all depths, though sparingly, between

1006 and 100 fathoms.

The table following seems to show that, as in hamata, only small specimens are found

near the upper limits of its distribution, the larger specimens are only found deeper.

Length.

| |

| Specimens. | |

| | Max. Min. | Average.

| mer, : | | |

I. Open nets lowered to 100 fathoms .......... | 5 11 | 9 | 10

| 1H, 5p 3 150, 200, 250 fathoms . .| 41 15 8 | iat

1000 ae a 300, 350 fathoms .... } | 1b 20 8 | 12

| Closing-net _,, 300-200 fathoms .... } | | |

| IV. Closing-net, various depths between 1000 Sa | 7 39 13 19

| 300) fathoms... dic oaae aera aes |

THE CHATOGNATHA. 69

SAGITTA BIPUNCTATA, Quoy & Gaimard. (PL. 5. figs. 28-31.)

Characters.—Head small; body slender, the middle third nearly of the same thickness

throughout, tapering slightly towards the head, more sharply towards the tail. Body

when preserved firm, not flabby. Longitudinal muscles broad, but not stout; lateral

fields of medium development; the sides of the body often shrinking inwards in

preserved material, so as nearly to conceal the anterior fins. Tail very slender.

Posterior fins fairly long, more on the body than on the tail, widest nearly opposite the

septum; shorter than in serratodentata, and not extending backwards nearly to the

vesiculee seminales. Anterior fins well separated from the posterior, very narrow, not

reaching to the ventral ganglion, shorter and narrower than the posterior. Tail-fin

rounded posteriorly.

Jaws strong, sharply curved in the distal half. Teeth broad below, closely apposed,

rather short and stumpy. Vestibular ridge with very slight prominences, about the

same length as the posterior row, projecting markedly at its external end *.

Haagen, Tene cE | Sag, | Antanas

20°0 22 10 5 13

19°5 25 10 4 18

18-0 22-25 9-10 6-7 13-17

160 | 21 10 5 15

140 | 21 9 5 14

130 | 23 9-10 5 10-12

120 25 9 5 12

tics. 9 22 9 5 8

LOO. 1" 20 8 4 8

90 22 9 5 10 |

A curious feature of the collection was the scarcity of this species, although, if the

determinations of some earlier observers are to be trusted, a plentiful supply might have

been expected. The explanation is probably correctly given by Steinhaus} in saying

dadurch 2u erkliren, dass sie mit der Stromung so weit yom Lande abgetrieben ist.”

On the other hand, during the homeward voyage, a haul in about 40 fathoms on

* Only traces of the corona were retained in my specimens. A good figure is given by Hertwig, Jen. Zeitschrift,

L880, pl. iv. fig, 20.

70 DR. G. H. FOWLER—-BISCAYAN PLANKTON :

Parsons Bank at the entrance to the Channel produced such hundreds of dipunctata

that the contents of the bottle looked more like vermicelli soup than the results of a

tow-net.

The captures in the Bay of Biscay were only six in number (seven specimens in all),

and all occurred at less than 200 fathoms in open nets; the hauls were 25g (50-0);

33 h (75-0); 32d, 827, 32 p (100-0); 386g (200-0). From the Parsons Bank specimens

T have deduced the preceding table, and have given a definition and figures to bring the

species into line with the others here described.

SAGITTA DECIPIENS, sp. n. (PI. 5. figs. 32-35.)

Characters.—Head and body of the proportions of bipunctata or serratodentata, to

both of which it bears a strong resemblance; it carries, however, large ova at a very

much smaller size. Body very slender, thickest behind the middle of its length,

tapering very gradually towards each end. Neck not well marked; collarette very slight.

The whole body very transparent, but firm, and retaining its shape. Anterior fin long

and narrow, not reaching to the ventral ganglion. Posterior fin about the same length,

broader, more triangular; about equally on trunk and tail, widest part at or just behind

the septum. ‘Tail-fin truncate. Corona not observed; ventral ganglion prominent.

Ovary short and thick, very opaque in the transparent body, extending when apparently

ripe as far as the anterior end of the posterior fin. Ova comparatively very large.

Jaws curved slightly, slender; external pillar small or absent. Posterior teeth long

and closely apposed; anterior teeth shorter, triangular, with broad bases. Vestibular

ridge prominent, with thick cuticle; a very strong process, sometimes forked, at the

external edge, extending further at both ends than the row of teeth.

The following table has been summarized from 20 specimens.

| |

insets | TRE | ery || ee

115 30 5-6 | 6-7 15

10°5 28 6 | 7-8 i sreaae

10:0 25-30 Fa | 6-9 | 1-17

9-5 31 6 | 6-7 | 13-15

| 9-0 33 526 5-10 12-18

| 8-0 30-37 5-6 8-9 13-16

| 75 40 6 | 8 14

6 6 | 9 16

Distribution.—As regards the distribution of this form, the occurrences as recorded in

the general table, although correct so far as they go, must not be taken necessarily to

indicate the extremes of its habitat upwards or downwards; this follows from its small

THE CHATOGNATHA. TT:

size, which makes the separation of young specimens from young of serratodentata and

similar forms extremely difficult. The table at least yields positive information of its

occurrence as high as 100 fathoms or less, between 150 and 50, and between 200 and

100 fathoms. Below the latter zone it failed in the closing-net, and probably does not

exist. But it may have reached a higher level than 100, for in three hauls in the open

nets at 75 and 50 fathoms I took young specimens which I cannot satisfactorily identify.

The foregoing species were for the most part abundant and well-characterized.

But there remain a few specimens to which I dare not give a definite name, for want of

sufficient material. As they may help to extend the observations of some future worker,

I append a few notes on them.

SAGIrra sp. indet. ? juv.

In open nets lowered to depths between 50 and 250 fathoms, and in one closing-net

(200-100), there occurred a number of small and immature specimens of a very slender

type, which I dare not assign to any species. Their figures, when summarized, are as

follows :—

| | | |

: Tail as p.c. of : Anterior | Posterior

genau length. Jaws; teeth. teeth.

9 27-33 6-7 5-6 8-11

8 25-31 6-7 4-6 8-9 |

i 28 7 4-5 8-9 |

They occurred in the following hauls :—

25e 35 e 369 36%

35 b 35m 36h 36k

35 d 36 e

They resembled young serratodentata, but showed neither the characteristic hooks nor

serrations of the jaws. They bore a still stronger resemblance to decipiens, but the

posterior teeth seemed hardly numerous enough for that species. They might be young

decipiens, or zetesios, or possibly a separate species, but they are almost certainly not

— young furcata or macrocephala.

Saeirra ? PLANCTONIS, Steinhaus. (Pl. 6, figs. 36-40.)

Under this head I rank three well-preserved specimens of doubtful relation. They

bear a close general resemblance to zefesios, but differ in that the anterior and

posterior fins are nearer together, the anterior fins reach further forward (in one to the

end, in two to the middle of the ventral ganglion), the widest part of the posterior fin is

SECOND SERIES.—ZOOLOGY, VOL. x. 12

72 DR. G. H. FOWLER—BISCAYAN PLANKTON :

level with or behind the septum, the posterior fin is rather more on the trunk than on

the tail; the teeth are shorter and thicker, and less closely appressed together; the

numbers of posterior teeth are much smaller for the length.

In general characters and in the numbers of the armature they stand closest to

planctonis, Steinhaus, except for the fact that the anterior fin is rather wider posteriorly

and a slight collarette is present: of the detailed characters of the jaws and teeth in

planctonis we have no information.

SS YOSSH Gar cnc 22 | 25 8 6-7 9-10

B Dili eas. cee 16 25 9 4 7

a { DAW chit. cee 14 28 8 4-5 i

( planctonis, Steinhaus ..........) 25 8 | 5-6 up to 12

| furcata, Steinhaus ............ | 20 7-10 | 6 | 8

g tepeneeasaGuoy et Gaimaraiat | 25 | eaieatne 4-8 10-15

: neglecta, Aida* .........0.0.. 25 | 8 4-5 10-12

8 | regularis, Aida .........00... 30 | i. 2-4 5G

a | Méspida, Conantiteen t:): 60s 25-33 | 7-9 | 4-8 8-17

Ee flaccida, Conant .............. 16 | 8-9 (pe 10-12

8 ZenwWism COMA Meta «cr. iors 25 | 7-8 4-5 | 7-10

r Ghats, Vicia, 5 os eeae seer ao. 20 | 8-12 5-7 | 12-15

\\ pulchra,; Doncastery........ 5.2. | 16 6 6 +10

1 Aida’s neglecta is almost certainly bipunctata, Quoy et Gaim., and his bipunctata = Bedoti, Béraneck.

It is not worth while to enter into detailed differences between all these species * and

my specimens, but the following rough points will serve to differentiate them :—They

are stronger in build (7. e. stronger longitudinal muscles and smaller lateral fields) than

Jurcata, much broader and less pin-shaped than bipunctata. The description and figure

of neglecta are so generalised and give so little detail that it is impossible to say whether

this, if a “ good” species, has any relation to our specimens. From regularis they are

readily differentiated by general outline (¢f Aida’s fig. 17). They are too stoutly built

* If is hard to believe that all the above are separate species. It is even harder to reduce their number, since most

of them are quite insufficiently described, and the figures (when they exist) are generally as inadequate as the

descriptions.

THE CHATOGNATHA. 73

to be flaccida or tenuis, and the general outline is quite different from that of hispeda.

Elegans is said to be very much like dipunctata, which cannot be said of these specimens.

The limitation of the corona ciliata to the body sufficiently separates it from pulchra.

There remains a certain number of specimens with more or less hexapterine numbers

of jaws and teeth, and of the pliant flabby hexapterine type and proportions. These

may include more than one species, but the examples are either so few or so badly

preserved that, not having handled as yet large numbers of undoubted hevraptera, I

prefer to leave them somewhat vague. So far as the numbers of teeth and jaws are

concerned, most of them can be fitted only into heraptera (d’Orb.), magna (Langerhans),

or tricuspidata (Kent). Dr. Krumbach has already expressed his belief that hevaptera

and magna are synonyms: with this I agree (so far as is allowable without a comparison

____ of type specimens), at any rate as regards the magna of Langerhans; whether Grassi had

the same species before him, or not, is hard to say. I incline further to add ¢récuspidata

as yet another synonym, having before me large specimens from the ‘ Siboga’ expedition,

which by the numbers of the armature are ¢ricuspidata, but in other respects agree

sufficiently with hexaptera. Kent’s original diagnosis of tricuspidata was not adequate :

except for the armature numbers, it might be applied to several species, and his figure

_ might stand for an inflated hexaptera ; it has certainly a more apoplectic look than most

hexaptera, but the proportions of the body alter at death in very different directions

_ among these less rigid forms, and I have noted a greater difference in general form

_ between two specimens of furcata than exists between Kent’s figure of ¢ricuspidata and

the ordinary drawings of hexaptera.

(i.) A few of these specimens are probably attributable to Sagitta? hexaptera,

d’Orbigny, itself. They occurred as follows :—

| | |

ve eed 7 ;

BEES Wats lacre si «:a 14 21 | 7 3 3

2 GSO SORE ee 11 22 ul 3 2 |

Bee a... 36 25 6-7 4 4

Species indeterminate.

(ii.) From several hauls came specimens of which the cirrhi were either in excess of

those recorded for hevaptera, or were present in very small specimens to the

number of eight, the maximum number in the largest hexaptera as yet recorded

(if Grassi’s magna be omitted). Some of these were probably young Surcata,

: others may be the young of other species.

They may be summarized as follows :—

32¢

74, DR. G. H. FOWLER—BISCAYAN PLANKTON :

| |

tinge ma, | TA ESMt el e! | Bat

22 26 | 10 5 5

| 20 22 8 5 3

19 21-26 8-10 3-4 4

| 15 26-31 | f 3 2-4

13 23 | 8 3 4

12 25808) Vail WMesig 3-4 2-3

10 25 | 8 2 3

| 9 07-33 | 84i 2-4 2-4

They occurred sparingly between 50 and 500 fathoms.

(iii.) Three large specimens of hexapterine appearance, much compressed, will probably

be easily identified by any future observer who takes this species, from the

remarkable character of the most dorsal (youngest) jaws (Pl. 6. fig. 41).

These specimens came from 500 and 250 fathoms.

Haul. Length in mm. iene vs Jaws. a ar ee

E a

ZO Ga aime nicer 33 NG 6 7-8 8

ZONA justo veuere 29 20 ii 4-5 8

PA Ree oa cee 28 18 3 7 3

The last specimen had certainly lost some jaws, of which the sockets were to be seen,

and probably some posterior teeth. They might possibly be fwrcata, dead and sinking,

for the younger jaws in this species resemble those figured in form, but are less strong:

against this was the length and sharpness of the teeth, nor did the fins exactly resemble

those of furcata.

KRrounia HAMATA, Moebius. (PI. 6, figs. 42-46.)

Characters.—Head small; body slender, resembling bépunctata, firm, retaining its —

shape (except when considerably damaged), thickest in the middle third, tapering

gradually to both ends; neck fairly well marked; no collarette. Lateral fins long, not

extending posteriorly nearly to the vesicule seminales, but beginning only a little way

behind the septum; widest point at or just in front of the septum; fin-rays extending

about as far in front of the septum as the fin does behind it, but the fin continued

THE CHATOGNATHA. 75

forwards * as an expansion of the epidermis up to or to the middle of the ventral

ganglion. Tail-fin truncate.

Jaws slender, not strongly curved, the tips bent through nearly 90° into a hook f.

Teeth broad below: in old specimens very closely set, long, and sharp. Corona ciliata

not observed f.

Distribution—Some years ago, in a most instructive paper, Prof. Chun § discussed

the known occurrences of this species, and utilised them to illustrate the theory that the

alleged similarity between the epiplankton of subarctic and subantarctic || regions

might be explained by these two cold-water faunas being really continuous by way of

the cold deep water of the main oceans.

According to the theory, hamata, an essentially cold-water form, should at low

latitudes (high upper temperatures) fail in the epiplankton, but be captured in the

mesoplankton.

In my Faerce Channel cruises, hamata was fairly plentiful in the epiplankton, but

occurred with even greater regularity in the mesoplankton ; apparently like some other

supposed subarctic forms, it showed even at that latitude a preference for the deep cold

water, water which in that area was purely of arctic origin.

It is, therefore, very interesting to find that, even as far north as our positions during

the 1900 cruise, it failed altogether in hauls at the surface or 25 fathoms; it appeared

once only at 50 fathoms J, twice at 75 fathoms, but regularly at deeper horizons down

to 2000 fathoms.

7 At 0 fathoms it occurred in 0 out of 25 hanls = 0 per cent.

oy) 25 ” ” OTF: 2 , = 0 ”

» 50 »” ) l 5 13 ” =7 »

»” 75 ” 5B) 2 ” ll ” =18 ”

” 100 ” ey) 14a 35 =63 »

1000

» | to ‘ ” ” 22 , 9380 ,, =73 ”

100

2000

” | to ‘ ” ” lies ie 35 =14 ”

1000

This table shows clearly that while odd specimens (and, as a matter of fact, tiny

specimens) may range exceptionally as high as 50 fathoms, it is between 2000 and 100

fathoms that this species is to be sought. Below 1000 fathoms it was only captured

* This is so constant in apparently perfectly preserved specimens that I have no doubt that it is a normal

structure.

+ This is less marked in tho older (ventral) teeth of old specimens, probably the result of wear.

' ¢ Figured by Strodtman, Arch. Naturgeschichte, 1892, pl. xvii. fig. 18.

§ C. Chun, ‘ Beziehungen zwischen dem arktischen und antarktischen Plankton,’ Stuttgart, 1897.

|| In the discussion of this alleged ‘ Bipolarity,” the issue has been obscured to some extent by loosely terming

the regions under discussion “‘ arctic ” (Labrador, Greenland, Iceland, N. Norway, cc.) and “ antarctic” (Patagonia,

§. Georgia, the Kerguelen area, &c.). These regions are more correctly classed by temperature as subarctic and

“subantarctic : between the faunas of truly arctic and antarctic regions, with a permanent sea temperature of 0° C. or

thereabouts, no real resemblance has been shown.

4 This haul, 25 ¢, is under suspicion: it may be a portion of 25 d, 100 to 0,

76 DR. G. H. FOWLER—BISCAYAN PLANKTON:

once by the closing tow-net, but large specimens were also captured by the closing trawl

between 2000-1000 and 1500-750 fathoms. The species, then, in this area is meso-

planktonic, and certainly ranges as deep as to the zone 2000-1500, probably to deeper

water still.

The captures, however, enable another point to be made, namely :—that older (larger)

specimens do not frequent even the upper zones of the mesoplankton, but the deeper

strata only. Specimens more than 17 mm. in length—and this is small for hamata—

were met with only below 500 fathoms.

Hoszonlsn Number of = Maximum Average

3 ‘ specimens | length length

| HBUDO RE | measured. | in mm. | in mm,

| Open tow-nets ....| 0

| 25 | |

50 | 2 11:0 | 10:0

7B. cogil 4 [PSE \ae 108

100 98 135 | 105

| 150 27 15:0 11-9

200 ial 13°0 11-4

| 250 | 139 155 13-9

300 53 | 17:0 13:6

350.. | 38 |= ale=0 127

Closing tow-net ... | 500 to 100 | 28 17:0 11:8

| 750 to 500 | 16 27:0 18:8

| 1000 to 750 | ll 28-0 21:3

| 2000 to 1000 | 1 | 200

Closing trawl ...... | 1500 to 750 | 1 | 33:0

| 2000 to 1000 | ey me 23-0

We may fairly conclude from this table that in the area studied the older specimens

are to be found in the deeper strata of the mesoplankton only, though the young forms

may frequent higher levels. Only small specimens occurred above 500 fathoms, large

specimens only below 500, but small specimens also occasionally occur below 500.

This touches a question of great interest, at which, so far as I know, no connected

work has been done. The young of epibenthic and epiplanktonic forms mostly spend an

early or larval life at the surface: where do deep-water oviparous forms, whether

plankton or benthos, spend their early life? Do they similarly seek higher levels? and,

THE CHATOGNATHA, vir]

if so, do they range also to the surface ? The answer for hamata appears to be, that

they rise higher, but stop short of the surface; zefesios apparently follows the same

habit. Of course where, as in the subarctic region, the species is epiplanktonie, the young

are also epiplanktonic.

The materials are now to hand for a fairly complete idea of the distribution of

K. hamata in the Atlantic. As an epiplanktonic and mesoplanktonic form it ranges

from 81° N. (Romer and Schaudinn) over the North Atlantic, from Greenland and the

Labrador Current in the west to Spitzbergen and Lofoten in the east, occasional drifted

specimens reaching along the Norwegian coast into the Baltic. In the Faeroe Channel

with comparatively high surface-isotherms, it shows a preference for the mesoplankton,

although also occurring less plentifully in the epiplankton *. Passing southwards—in

the Bay of Biscay it was purely mesoplanktonic. In the South Equatorial Current the

same holds good; only young specimens were obtained by the ‘ National,’ and only by the

closing-net at considerable depths +. Still further south, young specimens were obtained

from a depth not greater than 38 fathoms, at 40°S., by Dr. Schott and Captain Bruhn ¢ .

in other words, the species rises nearer to the surface at high latitudes with a lower and

more suitable surface isotherm. Lastly, I am glad to be able to complete the series by a

well-preserved and unmistakable specimen captured at or close to the surface by my

friend Mr. Vallentin at the Falkland Islands, well within a subantarctic district.

Krounia HAMATA, Moebius, var. (PI. 6. figs. 47-49.)

Among the hamata were a few specimens which could not be quite reconciled with all

the characters of Moebius’s species, although probably only a variety. There were two

well-preserved specimens of 23 and 12 mm., the smaller serving to connect with some

yet smaller larvee. They differ from hamata in the possession of a stouter body, with a

less marked taper, of somewhat more curved jaws which seem longer in comparison

with the head; the tips of the jaws are longer and only slightly bent. Fins similar in

both.

The specimen figured (30e, 23 mm. long) exhibited the characters thus described ;

there were also heads and damaged specimens from some other hauls, of which at any

rate the jaws and teeth showed the same or an intermediate variation from hamata. So

likewise did the five small specimens in the table; these were further characterized by

a ferocious-looking sagination of the jaws: a similar sagination has been described by

Strodtmann in some young specimens of hamata, which I can confirm from Faeroe

Channel material. The saginate jaws are the more ventral (older). ‘The 12 mm.

specimen seemed to suggest that the ultimately smooth outline of the jaw was attained

by a filling-up of the spaces between the saw-teeth.

The occurrences of this variety have been reckoned as hamata in the previous calcu-

lations, in the notes on general distribution (p. 81), and in the diagram (PI. 7).

* The observations on which this statement is based have not yet been published.

t O. Steinhaus: op. cit. supra, p. 34.

} O. Steinhaus: op. cit. supra, p. 47.

78 DR. G. H. FOWLER—BISCAYAN PLANKTON:

Haul. aH pa aa es 2 Jaws. Teeth.

AOGe5e0cscg06 23 26 12-13 13

DGiO aie airetndere 20 25 9-10 9

De atoietrene | 12 25 10-11, 3 saginate. 10

BPasocudoade 9 27 HORST es 5

| Beas mete 8 25 TIE ne 4

| SU seeepeteietere if 28 Ma 3-4

eel ae don ac 6 33 OnOM aes 2

KROHNIA SUBTILIS, Grassi. (PI. 6. figs. 50-52.)

Characters.—Head of moderate size; body extremely long and slender, transparent,

not firm and rigid like hamata at a corresponding length; thickest at about the middle of

its length, but even here only slightly thicker than at the neck, the taper extremely

gradual. Neck fairly well marked; a slight constriction at the septum. Lateral fins

very long, reaching from the vesicule seminales to a third of the distance between

Delia | al re ee

ee 36 7-8 11-12

15 40 7 a

a 35 7-8 u

F 35 7 12

ey 35 8 10-11

Bs 30 9 u

12 33 8 s

W 36 s 9-10

9 33 6 10-11

8 | 37 8 7

septum and ganglion, about two-thirds on the tail and one-third on the body, widest at

or in front of the septum; fin-rays present throughout its length. Tail-fin truncate,

extending anteriorly to the vesiculee seminales. Jaws strongly curved, very sharp,

usually thin when viewed from the outside. Teeth similarly thin plates, bayonet

shaped *. Vestibular ridge (apparently) absent ; corona ciliata not observed.

* Compare Grassi, pl. i. figs. 9, 10.

THE CHATOGNATHA, 79

I can find no distinction between this species and Aida’s pacifica except in the corona,

which in pacifica is confined to the trunk, and in subtilis extends also on to the head.

As, however, it was not figured by Grassi, and is only one out of several characters, it

seems fairly safe to put the two species together. ‘The teeth are not always so numerous

as Grassi’s number of 18, nor does the head look large unless the cheeks are thrown out

and the jaws turned in, in the death contraction.

Distribution—This species was comparatively scarce. It failed altogether at the

surface and 25 fathoms, and was taken only six times in all (18 per cent.) at 50, 75, and

100 fathoms. It failed in all the closing-nets, but appeared in hauls with open nets at

200, 250, and 300 fathoms. The only positive evidence therefore of its distribution

points to its habitat being between 50 and 100 fathoms; but the species being so scarce

in the locality, too much weight must not be laid upon this.

GENERAL REMARKS ON THE VERTICAL DISTRIBUTION *.

In handling the captures as a whole, the hauls with open tow-nets can be compared

together with fair accuracy, and the hauls with the mesoplankton nets are similarly

comparable amongst themselves. But while the former were lowered to a set depth, and

towed horizontally at that level for a fixed time (generally an hour), the mesoplankton

closing-net was opened at the lowest depth and drawn up vertically through a compara-

tively small quantity of water before closure f.

The mesoplankton net therefore cannot be expected to capture so many specimens as

the open nets used at higher levels. At the same time the hauls were so numerous, that

only rare species can have uniformly escaped.

In the following tables, therefore, all hauls which could be usefully compared have

been divided between the open nets and the closing-nets.

1. Hauls with open nets.

At 0 \ 169 | 81 \ Tolie = 106

25 52 7 | & 12 = 43

BO | 239 | 100 g 13 2 188

75 241 | 2 LO ea, «lt 2% 21:9

Ho | 5 881 | £ 100 / | 8&2 400

150 | 8 21 | 8 i se 21-0

200 | & 2 | = 1| 8 120

250 | 101 2 ms 50°5

300 37 a a

350 33 De fin Bs ll S80

* As in dealing with serratodentata and furcata above, nine hauls with a small-mouthed net and 180 meshes

per linear inch have been omitted from the following calculations. The captures in al] open nets have been treated

with a time-factor to bring them to the standard one-hour haul. The captures by the closing-net towed through

250 fathoms have been divided by 2°5, and through 500 fathoms by 5, to bring them to the standard 100-fathom

haul. 21 (open for 50 fathoms only) and 21 @ (a closing-net which arrived open at the surface, a miss-fire of the

gear) have also been omitted as not being in line with the other mesoplankton hauls.

+ Compare supra, p. 4.

ECOND SERIES.— ZOOLOGY, VOL. X. 13

80 DR. G. H. FOWLER—BISCAYAN PLANKTON :

From this table it may be inferred that Cheetognaths were less plentiful (or more

migratory) between 0 and 50 fathoms: that the population increased down to 100 fathoms

at least. Below that level the hauls were scanty and the figures therefore are much less

reliable: not only so, but it must be remembered constantly that these open nets,

and especially the deeper hauls, pick up a large quantity of specimens on their upward

journey which belong to shallower horizons*. The 250-fathom hauls, for example,

represent not only the captures in an hour's slow horizontal towing (say a mile and half),

but also those of 250 fathoms vertical towing at a greater pace— a very considerable

addition. Now it is a fair inference from the above, that if the population below

100 fathoms were as large or larger than at that horizon, the average captures should

number considerably more, whereas, except in one instance +, they are less than at

100 fathoms. Hence we may conclude that the’ population diminishes below 100 fathoms

or thereabouts. This conclusion is confirmed by the more accurate method of the

closing-net.

ii. Hauls with the closing-net.

Between 150-50 \ 16 ‘N 1 \ 1 \ a 16:0

200-100 dg.) 6 | 7 ea)

250-150 | in| 2 3 E25

s00s200 © |) Mar! vert) 8 RS 3 | gs 20

400-300 8 SN i | hes ~ 2 3-0

500-400 | 3 107" 5 3 a 3 = 3 3:3

750=500 "|" 2 “164r iF a ae oe oe Be 41

1000-750 | 8 | 11-2 |e aan eee a ae

1250-1000 1:2? 3 3 3 0-4.

1500-1250 ol 0 2 8 0-0

2000-1500 } 1-22 1 ay * 0-6

* Number captured divided by 2:5. * Number captured divided by 5:0,

The sudden drop in the last column after 200 fathoms is most instructive: from 200-

1000 fathoms the figures are small, but as steady as could be expected from the com-

paratively small number of hauls. Below 1000 fathoms is apparently another drop;

but even at this deepest stratum there can be no question of the presence of quite large

numbers of Cheetognaths even at the lowest depth investigated; for example, the three

hauls 1250 to 1000 fathoms filtered only a cube of about 16 feet each, but produced

one specimen each. Haul 260 (2000-1500 fathoms) was towed at about 1900 fathoms

* Of course exactly the same criticism applies to my hauls with open nets at 25, 50, 75, and 100 fathoms; but

with much less force, for these hauls were only towed upwards through a small fraction of their horizontal tow

(instead of a large one), and were made in such numbers as practically to eliminate error by comparison. Below

100 fathoms the ratio of vertical to horizontal tow becomes serious, unless very prolonged horizontal hauls be taken,

which is bad for the material captured.

+ Namely 250 fathoms. Of the two hauls concerned, the one contained considerably more (72), the other

considerably less (29), than the average for 100 fathonis.

THE CHATOGNATHA. Sl

for an extra twenty minutes, as a steamer collided with us in the middle of the operation

and stopped proceedings for that period; it produced five specimens belonging to two

species.

In the diagram, Pl. 7, I have endeavoured to express the comparative distribution

of Cheetognaths as a whole at all depths, and also some points in that of the common

species. (1) The lines labelled decipiens and zetesios merely record the vertical extension

of these two species from positive observations (that is, closing and shallow open nets ;

the deep open nets being regarded as untrustworthy): they did not occur in sufficient

numbers to give any indication of a centre of distribution. (2) The three diagrams

marked serratodentata, furcata i., and hamata i. represent, as ordinates to the curves,

the average number of specimens per hour haul by open nets at various depths. They

seem to show that serratodentata is most plentiful down to 100 fathoms, furcata most

plentiful from 50 to 150 fathoms, and that these upper hamata (which are all very young

specimens, p. 76) are numerous between 150 and 300 fathoms *. These three diagrams

are all drawn to one scale, and the ordinates to the curves are placed at the lowest or

towing-depth of the net. (3) The remaining four curves deal with the closing-net, and

are also all drawn to one scale. They are not to be compared with the foregoing curves,

because they represent, as ordinates to the curve, the average number of specimens per

100-fathom haul of the closing-net at various depths. The ordinates in this case are

placed in the centre of the zone studied: thus the ordinate for 150-50 fathoms is drawn

on the 100-fathom line. The curve marked furcafa ii. shows that the population, high at

150-50, drops suddenly between 200-100 fms.; below this zone the species was not

captured in closing-nets, and presumably does not occur t¢. The curve marked hamata ii. ¢

shows clearly enough the influence of a large number of young specimens between 200-100

fathoms. Both hamata ii. and macrocephala curves seem to show a rise in population

between 750 and 500 fathoms, as indicated by the ordinate on the 625-fathom line: this

is of course repeated in the curve of general capture of all species. Whether this really

indicates a zone of thicker life here or not, will be more easily seen when other groups

have been worked out, but I certainly noticed the same rise in population when counting

the Copepods in a series of typical hauls. The curve marked “all species together ” is a

graphic expression of the last column in the table on page 80. Unfortunately it by no

means agrees with the only previous attempt to deal with the vertical distribution of

Cheetognaths as a whole.

Last year Mr. R. T. Giinther published a paper “ On the Distribution of Mid-water

Cheetognatha in the North Atlantic during the Month of November” (Ann. Mag. N. H.

(7) xii. p. 384). Of his main general conclusions, the most important—namely, “ that

the upper hundred fathoms contain but few individuals as compared with the deeper

* The drop in this curve at 200 fathoms, based on a single observation, would probably have flattened out as

indicated by the dotted line if more observations had been taken,

T The specimens recorded in open nets below 100 fathoms were therefore probably caught in the vertical journey

upward : an instance of the deceptiveness of the method of open nets,

+ This includes hamata, var., p. 77.

13*

82 DR. G. H. FOWLER—BISCAYAN PLANKTON :

waters of the Atlantic ’—is, to my belief, absolutely deceptive, and must be attributed to

the faulty method of capture employed and to the consequently inadequate evidence laid

before him. In the first place, if one may argue from his diagram *, no hauls were taken

at depths between 50 and 200 fathoms. Now, as has been shown above, this includes

the most populous zone in the ocean, and is well known to be so from the results of other

expeditions. Apparently it was entirely passed over in these collections. In the second

place, the species not having been identified, the deduction entirely neglects the fact that

different species inhabit different depths. Lastly, the conclusion takes no count of the

weakness of the method of serial open tow-nets at great depths—namely, that it does not

eliminate the organisms captured in the upward journey at higher levels: this alone is

enough to vitiate the conclusion. The effect of the upward journey through what

(according to my results) are more populous zones can to some extent be gauged ‘from

the following observations :—My average specimens between 1250-1000 fathoms were

0:4; now hauls 27 4 and 27 a! missed fire, and the closing-net failed to close, its contents

therefore represent specimens obtained on the upward journey only. These two hauls

contained no less than 89 specimens belonging to six species; ten specimens belonged

to serratodentata and furcata, of which I was unable to prove the occurrence below

200 fathoms by the closing-net !

The closing-net brings comparatively little to the surface, but of this little we at least

know accurately where it was caught +; and when my curve of “all species together ”

is compared with Mr. Giinther’s result, there can be little doubt that a large proportion

of his specimens were caught on the upward journey.

With Mr. Giinther’s second conclusion—that small specimens are more plentiful at the

higher levels, large specimens are more characteristic of greater depths—I am in entire

agreement, although I fear we might not agree exactly as to levels. But, so far as my

results go, this follows from the presence at higher levels of young specimens which seek

deeper water when adult (compare pp. 68 and 76).

The only other attempts to record the vertical distribution of Cheetognatha as yet have

been made by Strodtmann and Steinhaus on the materials of the ‘ National’ (German

Plankton) Expedition. Unfortunately the results of the surface and horizontal hauls

have not yet been published ; only vertical and closing nets are available, and these only

for parts of the cruise. It is, therefore, of no value at present to compare the results of

the ‘ National’ and ‘ Research’ in detail; in so far as they overlap, they agree in the

main, except in that the ‘ National’ failed to prove the existence of Chzetognaths below

1500 m. (812 fms.).

SUMMARY OF THE OBSERVED DISTRIBUTION.

These conclusions are stated less dogmatically in the foregoing text: a reference to

* No detailed list of the hauls on this cruise has been published. Since the above was in print, I learn through

Mr. Y. H. Blackman that two hauls were made between the depths mentioned.

+ By disconnecting port and starboard engines, and using them separately as required, we were able to keep the

wire rope straight up and down: Mr. George Murray’s criticism of the uncertainty of the horizon therefore falls

(Journ, R. Geog. Soc, xiii. p. 153).

THE CHATOGNATHA. 83

the pages cited will give the necessary qualifications and the evidence. It is hardly

necessary to remark that all these statements refer exactly only to the area studied and

to the period of the cruise. They are not necessarily, many of them not even probably,

true for distant localities under different conditions.

Sagitta serratodentata was epiplanktonic, extending from the surface to 100 fathoms,

with the highest number of average specimens at about 50 fathoms (p. 59). It showed

no indication of a nocturnal rise and diurnal fall (p. 60). On the contrary, although not

affected during the day by the actual light-intensity of the moment, still on the whole it

sought the surface by day and deserted it by night (p. 61). During or after rain it

abandoned the surface even in bright daylight, the largest number of specimens being

then found from 50 to 100 fathoms (p. 61).

S. furcata was also epiplanktonic, with a maximum distribution between 50 and

100 fathoms (pp. 64, 81). Occasional specimens reached the surface and 25 fathoms, but

it was not taken below 200 fathoms (p. 64).

S. macrocephala was purely mesoplanktonic, ranging from 400 (?300) to 2000-1000

fathoms (pp. 65, 67).

S. zetesios was also mesoplanktonic, ranging from 100 to 1000-750 fathoms {p. 68).

At less than 300 fathoms only small specimens were taken ; the large specimens were all

from greater depths.

S. bipunctata, being apparently a neritic form, occurred very sparingly in the epi-

plankton (p. 70).

S. decipiens belonged to the upper mesoplankton; it was taken with certainty only

between 100 and 200 fathoms (p. 70).

Krohnia hamata was mesoplanktonic, never reaching as high as 25 fathoms, but

extending to the 2000-1500-fathom zone (p. 75). Above 500 fathoms only small

specimens of 5-17 mm. were found, extending into the lower epiplankton (p. 76); the

length of these smaller specimens on the whole increased with the depth, and

their maximum distribution was about 150-250 fathoms (pp. 76, 81). Only below

500 fathoms were large specimens to be found, mixed with a few small specimens, possibly

corpses.

K. subtilis occurred only in the upper mesoplankton and lower epiplankton, in too

small numbers for accurate deduction.

Chetognatha as a whole increased in numbers as one passed from the surface to

100 fathoms (p. 79), and diminished again in numbers between that level and 200 fathoms

(p. 80). At about 200 fathoms there was a sudden drop in the population, which then

remained fairly steady down to about 1000 fathoms (p. 80), with a possible indication of

a slight increase in the 750-500-fathom zone (p. 81). Below 1000 fathoms was a second

sudden drop (p. 80). Chzetognaths occur, however, in considerable numbers even at the

lowest zone studied, 2000-1500 fathoms (p. 80).

In the following table the first three hauls refer to the mesoplankton trawl, the

remainder to tow-nets of “ comparable ” hauls.

nay

pei

84 DR. G. H. FOWLER—BISCAYAN PLANKTON:

TABLE OF THE OCCURRENCE OF THE COMMONER FORMS.

Ss 3 S S

Depth i 3 3 Depth i s 3

epth in 5 SS Bs e in S ~ “8

fathoms. Ebb aS 8 3 g = Ss futons: Haul. ~ S yy 3 s

B 1 28 | 68S 4) alee £8 A Ae alae

Pe 5 SI $s SS) s = & 8 s =]

Soe | Sas ol aes S| ag i) Se all anes

500—250 29a 100—0 21h + + ore

1500—750 30a oe a6 re ais oo + 211 de +

2000—1000 | 30e An oe aS te + 224 a5 +

——_—_ ee (St a a ee a ee eee 246 ak =e aL ai

24d sc +

0 2Qle + 24e ate a5 ar ar

21f 25d + + Ps AS an

217 30g | + | + Arelh 8

0g. al eeemel wets 30h ae dhe Apo

We + 82d = ah aR +

229 + 327 si + bo i

236 a ee Bon | ot: | ae oa ees

23. 32 p + ote an sr

23d + ab 33 + +

23 e ye + 346 oe +

24e 34d oh ate

24 f ys fk 35d + + apo | ar

249 + 35d + + 30 +

24h oof + + +

247 -b 85x + +

24k 366 “ +

2a me + 36e + + + + +

256 + 150—0 36f +] + + | Shoal

5h ae 150—50 21p % + ais ate

25% 150—100 Qin of ar

251 200—0 Qla +

30¢ 369 Ke + + + +

32¢ 200—100 216 ao Me A xe =e

38.4 21o us + ‘ ae +

336 26e Dio +

25—0 26a + 84h + i oF

306 + 35m + + +

30 m + 3on + + + /

8la + | 85t ;

326 250—0 36h + + + +

32e Te 367 ar aif oe +

33. ae ae 250—160 850 sf + +

339 ap | 35p

84a 35s a ee aa ss is =

34g 300—0 36K ar et on aR ot +s

35 w oe 300—200 2le a ifs + a ae

36¢ oS eee 26 f 4 |e |

50—0 21g + 351 a Be i as 3 a

25e ar an ae 350—0 361 ots + P ar + SP

25q ae ae 400—800 Qk ‘2 xe 36 ah oleate

25k fic ar 821 P ace bo +

26¢ + + 35k ?

| 30d + + 500—400 21m aa + Ms +

307 + Te 35h cts Bs + |

316 ar + 357 + vo : a

32a + a 750—500 | 226 ak x Z co

82h + + 30% + 2 i" + |

33 ¢ si + 34e + ar 5 SF

33 f ls + 34f + ar 4 ts

36d Sic + 1000—750 23.4 + 5 : +

75—0 30f a + 27¢ '

329 + ae 31d = ae

| 32m + at | 32 f .

| 320 + aie 32k A ats + ta

83h SL + 1250—1000 | 24a 20 cin P

84e Fr ak 276 : ar

35a + at + 8le an

35¢ + ae 4 | 1500—1250| 25f

85 e + ab 307

B5y + aie 2000—1500 | 25e

36a + + 266 +

a78 he si

THE CHATOGNATHA. 85

APPENDIX.

CHATOGNATHA FROM THE FALKLAND ISLANDS.

My friend Mr. Vallentin was kind enough to send me six specimens which he collected

at Port Stanley in 1896. They included only two species.

KRoHNIA HAMATA, Moebius.

A well-preserved specimen of this interesting species has been already mentioned

(p. 77) as completing the chain of occurrences required by Chun’s theory of the con-

tinuity of the subarctic and subantarctic Plankton through the tropical Mesoplankton.

The specimen, from between the surface and 6 fathoms, was about 18 mm. long, with

at least 8 jaws and 11 teeth; the exact numbers could not be given without damaging

the specimen, as both jaws and teeth were turned strongly inwards in contraction.

SAGITTA SERRATODENTATA, Krohn.

There were five specimens, from the surface to 6 fathoms, quite indistinguishable from

the Biscayan specimens and agreeing with them in numbers.

Length. Tail as p.c. of if Anterior Posterior

mm. total length. sats teeth. teeth,

9 33 6 2-3 3

15 26 7 8 7-8

This species has already been recorded from the subantarctic region, obtained by

the Hamb. Magalhaens. Expedition (Steinhaus).

LITERATURE.

A list of the literature of Cheetognatha was published by Strodtmann :—* Die Syste-

matik der Cheetognathen,” Archiv fiir Naturgeschichte, lviii. p. 833. This was supple-

mented by Steinhaus, ‘Die Verbreitung der Cheetognathen im siidatlantischen und

indischen Ozean,’ Inaug. Diss. Kiel, 1896. Since then the following papers on the

system of Cheetognatha have appeared :—

T. Ama.— Cheetognaths of Misaki Harbour.” Annot. Zool. Japon. i. p. 13 (1897).

L. Doncasrrr.—“ Cheetognatha.” Fauna and Geog. Maldive and Laccadive Archipelagoes, i. p. 209.

T. Krumpacu.— Ueber d. Greifhaken d. Chitognathen.” Zool. Jahrb. (Abth. Syst. &e.) xviii, p. 579

(1903).

O. Srzinnavs.—“ Chetognathen,” in Hamburg. Magalhaens. Sammelreise, Lief. y. (1900).

86 DR. G. H. FOWLER—BISCAYAN PLANKTO:

EXPLANATION OF THE PLATES.

PLATE 4,

Tig. 1. Sagitta serratodentata. x7.

. Ajaw. 105.

. Tips of two jaws. x 430.

. Teeth of the left side, from the ventral surface. x 210.

. Vestibular ridge of the left side, from the ventral surface. The tips only of the posterior teeth

are shown. x 210.

ob Oo wo

6. Dorsal view of the anterior end, showing the corona ciliata. x 24.

Fig. 7. Sagitta furcata, Stemhaus. Very well preserved, except for a shrinkage inwards of the lateral

fields, which carries the anterior fins nearly out of sight. x 35.

8. The same, perfectly preserved, representing the supposed living outline. x 3:5.

9. The same, badly preserved and dorso-ventrally compressed : the epidermis in the posterior two-

thirds flattened and loosened, making the fins appear too broad, and forming a /yra-like bridge

between the lateral fins. x 3°5.

10. The same, very badly preserved, violently contracted antero-posteriorly and somewhat compressed

dorso-ventrally. The epidermis very greatly flattened and corrugated. x 6.

11. Corona ciliata and eyes. x 60.

12. A jaw. x60.

13. Anterior and posterior rows of teeth, from a cleaned specimen. x 106.

14. Vestibular ridge, ventral view. x 106.

15. Vestibular ridge, anterior view with teeth in place. x 106.

PuateE 5.

Vig. 16. Sagitta macrocephala, sp.n. x9.

17. The head, from the ventral surface. x 24°5.

18. The vestibular ridge and posterior teeth of the left side, from the ventral aspect. x 105.

19. Ajaw. x49.

20. The first and last tooth, and four from the centre, of the posterior row, from a cleaned specimen.

The thickness of the bar 6 is also indicated. x 105.

21. a. The teeth of the anterior row, from a cleaned specimen, seen from the anterior end. 6. The

smallest tooth, from the dorsal surface. x 105. .

Vig. 22. Sagitta zetesios,sp.n. X4.

23. Specimen 32 mm. long, probably referable to this species, with an (artificial ?) expansion of the

epidermis in front of the anterior fin. x2.

24. Vestibular ridge of the left side. x 60.

25. Anterior teeth, from a cleaned specimen. x 105.

26. Posterior teeth, from a cleaned specimen. x 105.

27. Ajaw. x3.

Fig. 28. Sagitta bipunctata, Quoy et Gaimard. x3.

29. Ajaw. x 140.

30. Anterior and posterior teeth of the right side. x 140.

31. Vestibular ridge, showing position of first and last tooth. x 140.

Fig.

. Vestibular ridge of left side, ventral view. x 140.

. Anterior teeth of right side, in situ. x 140.

. Posterior teeth of left side, in situ. x 140.

4l.

. Krohnia hamata, Moebius. x4.

. Ajaw. x106.

. Tip of ajaw. x 520.

. The teeth. x 210.

. Corona ciliata. x61.

THE CHATOGNATHA.

. Sagitta decipiens, sp.n. x7.

.Ajaw. x140.

. Anterior and posterior teeth of left side, nearly from the anterior aspect. x 210.

5. Vestibular ridge, showing position of first and last tooth. x210. The strong cone on the

external surface is not always so well developed.

PLATE 6,

. Sagitta ? planctonis, Steinhaus. x6.

37.

Dorsal view, showing relation of coroua ciliata to head and to ventral ganglion, patches of

sense-cells, “neck-fin,” &c. x17.

Sagitta sp. indet. (iil.), p. 74. Three jaws. x19.

. Krohnia hamata, var. x4.

. Tip of ajaw. x 290.

. Saginate jaw of young specimen. x 290.

. Krohnia subtilis, Grassi. x 4.

. Ajaw. x 106.

. The teeth, drawn in place. x 210.

All figures have been drawn with the Abbé camera. The letters E and I indicate

respectively the external and internal aspects of the teeth, the vestibular ridge, &e.

PLATE 7,

Table of frequency of species of Cheetognatha according to depth.

SECOND SERIES.—ZOOLOGY, VOL. X. 14

Fow er. TRANS. LINN. SOC. SER. 2, ZOOL. VOL. X. Pl. 4.

11.

G. H. Fowler del, Langley photose.

BISCAYAN CHAZ TOGNATHA.

Figs. 1-6. Sagitta serratodentata ; 7-15. Sagitta furcata.

Fowzer. TRANS. LINN. SOC. SER. 2, ZOOL. VOL. X. PI. 5,

2 2 ae

—- >:

31. 35, a3 32

G. H, Fowler del. Langley photose

BISCAYAN CHATOGNATHA.

Figs. 16-21. Sagitta macrocephala ; 22-27. Sagitta retesios ; 28-31. Sagitta bipunctata ;

32-35. Sagitta decipiens.

Fowter. TRANS. LINN. SOC. SER. 2, ZOOL. VOL. X. Pl. 6.

SQ,

E I

A2.

sce

47.

G, H. Fowler del. Langley photose.

BISCAYAN CHATOGNATHA.

Figs. 36-40. Sagitta ? planctonis ; 41. Sagitta sp. indet. ; 42-46. Krohnia hamata ;

47-49. Krohnia hamata, var. ; 50-52. Krohnia subtilis.

suaidioep

8018999x

YBHLS9OL SNAWID3dS W1v

SER. 2, ZOOL. VOL. X. Pl.

SOC.

TRANS. LINN.

1 vypwny

DDYda00190UL

anaes Dre ee ae

1 vyp0inf~

[ 5 DID} UapoIv11asS

O ooze OOt 009 009 oooL 00z!

Fow er.

ogst swoyIng

TABLE OF FREQUENCY.

[ 89 ]

BISCAYAN PHANKTON.

Part IV.—THE THALIACEA.

By G. HERBERT Fow.er, B.A., Ph.D., F.LS., FZ.

(Plates 8 & 9.)

Read 2nd March, 1905.

Contents,

i, CycLomyaRia. Page

a. Gonozooids. Doliolum Tritonis, Herdman.............20.eeee0e 89

DBoliotum Kroknt, Werdman) 922+ -4s0 00 nee eee 90

DoliotumeNationalis, Borgertes\s acces oe eerie 90

Ol OLUTEDs, ebOrferbameeieie ee cea eee 90

6. Phorozooids. Doliolum Tritonis, Herdman ...............0-0+00- 91

DOV GWU SD, BOL BEL anette sa oernaiente tree ieee eialia= 91

c. Blastozooids. A (?= D. Tritonis, Herdman) ................:..- 93

UB Ee yeyaisy chey cies crore 8 wenn syatemeteuete rarenavehey nce cree Pee Ose: ce eNS 97

Doom: Arohni., Werdmanw. ariepremierisciteiseteiaeie 97

d. Trophozooids. A (? = D. Tritonis, Herdman).................--- 97

Disjovaransta¥n sieve a0! oduct le OO RPC LORE EET oa as eters 98

ii. Hemrmyarra.

Salpa runcinata-fusiformis, Cham. Cuv. .......0-e.ece cee eee ce eees 99

Stilyalee CAC GUL, aN bid) eee etic 5 CSB cicero ORE ao OOOO ETGne 99

Salpa democratica-mucronata ?, Forskfl ,......0.cceeece ee cceecece 99

i, THE CYCLOMYARIA.

Tis suborder was represented only by known species of Doliolum, but the collection

contained four apparently undescribed phases, two of which I believe to be the blasto-

_ zooid and trophozooid * of Doliolum Tvritonis. Of the four polymorphic life-phases of

_ Doliolum, the gonozooids alone have been adequately described for most species; in a

recent account of the genus, Dr. Borgert + gave a synoptic table which covered the

- gonozovids of all admitted species, but he did not attempt it for any other of the three

forms presented by this remarkable organism. It will be most reasonable, therefore, to

begin with the gonozooids; to pass to the phorozooids (since they are stated to be

structurally identical with the former, except internally for the absence of the generative

organs, and externally for the presence of the ventral outgrowth on which the gonozooid-

buds are borne and for the absence of the dorsal outgrowth); and to conclude with the

_ blastozooids and trophozooids.

a. Gonozooids,

Do1io.um Trironts, Herdman.

This cecurred at all depths down to 100 fathoms, but never below that horizon; it is,

therefore, epiplanktonic. But it did not occur in sufficient numbers (111), nor on

* Blastozooid = Amme. Phorozooid = Pflegethier. Trophozooid = Nihrthier. Gonozooid = Geschlechtsthier.

t A. Borgert: ‘ Plankton-Expedition. Thaliacea—C. Vertheilung der Doliolen.’ I follow his synonymy.

SECOND SERIES.—ZOOLOGY, VOL. X. 15

90 DR. G. H. FOWLER—BISCAYAN PLANKTON :

sufficient occasions (12), for inferences to be drawn as to its habits. Only small specimens

were captured ; the largest was about 5 mm. long, and many were less than 2 mm.

DoriotuM Krount, Herdman.

Two gonozooids only of this species were taken, one in 214, one in 30 h, both in 100-

fathom hauls.

DottoLtumM Narronatis, Borgert.

One specimen in 307 (50 fathoms) was apparently referable to this species.

Do.iouvM sp., Borgert.

Dr. Borgert (op. cit.) records specimens from the hauls of the ‘ National’ (coming,

with a single exception, ‘“‘aus etwas grésseren Tiefen,’ many of them from the closing-

net), which showed a marked resemblance to Krohni, Herdman, as regarded the

formation of the gills and alimentary canal, but recalled rarwm, Grobhen, in the form

of the generative organs. ‘To this unnamed species may be referred two specimens from

36 7 (350 to 0 fathoms). On comparison with Avohni, the main differences recognizable

were of the character noted by Dr. Borgert :—

Doliolum sp., Borgert. Doliolum Krohni.

Endostyle. . . . 1st intermuscular space to 2nd iatermuscular space to

5th muscle, 4th intermuscular space.

Gill-plate. . . . 4th to about 6th muscle. 5th muscle to 6th inter-

muscular space.

But he did not record, what was very noticeable in my specimens, the extreme thinness

of the muscle-bands, for they were as thin comparatively as in Nationalis, far thinner

than in Krohni. The gill-slits were not exactly countable, owing to poor preservation, —

but appeared to be about 16 to 20 in number.

Being unable, in a single case, to find a ripening ovum in this unnamed form, Borgert

suggested as a possibility that the specimens were examples of Avohni which had failed

to reach sexual maturity (supposing them not to constitute a separate species); or, as

an alternative, that the differences between them and Avrohni might be of a pathological

nature due to the depth at which they lived. There is, of course, also a third possibility,

namely, that these forms are really Krohni which, dying before sexual maturity or after —

sexual exhaustion, are sinking to the bottom, and that the differences in position of some —

organs are attributable to post-mortem shrinkage and to distortion due to tow-net

pressure. Like Borgert, I failed to find ripening ova, the cells of the ovary seemed to

be all approximately equal in size; but the whole appearance of this form is so different .

from Krohni, its muscle-bands are so thin, its test so slight, that I believe it to constitute

an undescribed mesoplanktonic species. My specimens are hardly good enough to allow

of a diagnostic description and figures. I suggest that it is a mesoplanktonic species,

not only from the ‘ National’ captures, but also from the distribution of the phorozooid

in the closing-net (p. 91).

THE THALIACEA. 91

b. Phorozooids.

DoxtiotuM Tritronts, Herdman.

This was taken in 138 hauls, all between 100 fathoms and the surface. Of the 119

specimens which I have assigned to it, a few may have been young gonozooids; but the

greater number (31) of minute specimens, which did not clearly show either generative

organs or dorsal outgrowth, have not been reckoned as either gonozooid or phorozooid.

No specimen exceeded 4 mm. in length. As we do not know at what length the phoro-

zooids become freed, and as so many minute but recognizable gonozooids were captured,

it must be left uncertain whether the larger phorozooids had been knocked off the dorsal

outgrowth of a blastozooid, or were leading an independent existence ; the former was

probably the case. Blastozooids which I refer to Trétonis were present in all the hauls

in which these phorozooids were taken.

Doniouvm sp., Borgert.

To this may be referred two specimens (35 0, 250-150 fathoms; 35 £, 430-300 fathoms) ;

and, with less certainty, on account of imperfect preservation, eleven further specimens

(21 m, 500-400 fm., 4 specimens; 21¢, 300-200 fm., 1 specimen; 31d, 1000-750 fm.,

1 specimen ; 27 a, 1250-0 fm., 5 specimens). No generative organs were seen, and the

specimens were therefore probably phorozooids.

ce. Blastozooids.

Very little is known of the specific characters of blastozooids. From the text and

figures of the more recent authorities I have compiled the following table, omitting,

however, two characters which are found in some definitions—the thickness of the

muscle-bands, because this seems to depend upon age and size; and the shape of the

true stolon, which appears (from my specimens, at any rate) to alter in successive phases

of maturation and germination.

In the table, to save space, the muscle-bands are represented by i, ii, iii, &c., the intermuscular spaces

by i-ii, ii-iii, &e. The authorities, indicated by square brackets in the table, are :—

A. Borgert: ‘Plankton-Expedition. Thaliacea.—C. Vertheilung der Doliolen’ (Krohni, pl. vi.

fig. 13).

C. Grobben: Arb. Zool. Instit. Wien, iv. 201 (Miilleri, pl. iii. figs. 16-18; denticulatum, pl. i.

figs. 3-5, pl. ii. fig. 7).

B. Uljanin: Fauna u. Flora d. Golfes v. Neapel, Monographie Doliolum (Miilleri, pl. vii. fig. 11,

pl. ix. fig. 6; Ehrenbergi, pl. xii. fig. 8). On p. 128 the anus of Miil/eri is described as opening

in v—vi, but is drawn as lying in vii—vili on pl. vii. fig. 11: this figure seems to be wrong in some

other respects—for example, the eighth muscle-band curves into the dorsal stolon and not the

seventh.

15*

92 DR. G. H. FOWLER-——-BISCAYAN PLANKTON:

CGsophagus

Intestine. Endostyle. et Anus. Gill-slits. Otocyst.

Miilleri, Krohn with U flexure. ii-ili toiv-v. under vi [U]j.], in y-Vl. v-vi to vi-vii, touching iv

[U]j., Gr.]}. in v-yi [Gr.]. small, [U]j.], on

iv [Gr.].

Krohni, Herdman with U flexure. ii-iii to iv-v. es. under vi, under vi. v—vi to yi-vii, ‘touching iv.

[ Borg. ]. stom, in y—Vi. small.

denticulatum, nearly straight. i-iii to iv—v. in y-vi. under viii. vy to vi-vii, in ilj-iv.

Q. & G. [Gr.]. large.

Ehrenbergi, Ulj., nearly straight. ii to iv—v. in y-Vl. under viil, v to vi-vii, in iii-iv.

not Krohn large. ’

[U]j.].

Blastozooid A nearly straight. —_ii-iii to y. in y-vi or from under y-vi to vi-—vii, in iji-iy.

“(2 = Tritonis, under vi. viii to ix. large.

Herdman) .

[G. H. F.].

Between the first two there is practically no difference, and but little distinction can

be drawn between the last three. Although the separating characters are not the same

in the two generations, the gonozooids of the first two species similarly belong to one

group of gonozooids, those of the last three to another.

Out of the numerous well-preserved blastozooids in the collection, not one had retained

on its dorsal outgrowth phorozooids of sufficient size to be identified specifically. The

experience of the ‘ National’ was similar; the older buds become very easily detached.

It is only, therefore, through indirect evidence that the blastozooids and trophozooids can

be linked with their proper species. Such evidence I propose now to attempt.

In 14 out of the 50 hauls at 100 fathoms or less which contained Doliolum of any

kind, occurred either gonozooids or phorozooids, or both, referable to 7riéonis, amounting

in all to 111 * gonozooids and 119* phorozooids. In 2 out of these 50 hauls were

found gonozooids referable to Krohni; in 1 only a gonozooid belonging to Nationalis.

Expressed in a comparative table, of the total gonozooids captured :

97°3 per cent. were referable to Tritonis,

ez 33 Sy ie Krohni,

8 y a S Nationalis ;

and there occurred gonozooids of :

Tritonis in 28 p.c. of hauls containing Doliolum,

Krohvi in 4 55 3 4

Natvonalis in 2 ., x er

Jn every one of the 50 hauls at 100 fathoms or less which contained Doliolwm of any

kind occurred blastozooids, amounting to 922 specimens. In about sixteen of these

* Actual numbers, not multiplied by time-factor ; all nets at 100 fm. or less.

—-— "F

ae ae

THE THALIACEA. 93

cases occurred small specimens, some 400 in number, which had not begun or had not

completed their degeneration, and therefore showed their characteristic structure: they

were demonstrably of a type hitherto undescribed. The remaining blastozooids

(excepting four, possibly five, specimens to be dealt with later) appeared to pass by easy

gradation into this type, though altered by the usual metamorphosis and degeneration.

In every case in which phorozooids of Tvitonis were captured this blastozooid occurred.

The presumption is that this undescribed blastozooid belongs to one of the species

already captured in the North-eastern Atlantic, namely, to denticulatum, Nationalis,

Krohni, Tritonis, or sp., Borgert *. Of these, denticulatum is known only as a warm-

water form, and has not been taken north of 42° N.; D. sp., Borgert, is apparently a

deep-water form, and I did not take it above 250-150 fathoms; the blastozooid of Krohn

has been well figured and described, and does not agree with the one before us; there

remain Nationalis and Tritonis. As between these two, the presumption is enormously

in favour of the one to which belong 97 per cent. of the gonozooids and all the

phorozooids. In default, therefore, of characters which enable older blastozooids to be

specifically differentiated, I refer all blastozooids from the epiplankton (except the five

already referred to) to

Buastozoorp A (? = Dottotum Tritonis, Herdman).

The table (p. 92) and the drawing (Pl. 8. fig. 1) sufficiently show the diagnostic

characters.

In the case of the Thaliacea, as in that of the Chetognatha, I have endeavoured to sort out every

specimen in the collection. That this is practically impossible, especially when dealing with minute

specimens, I know well; even if every particle of the catch were sorted out into its respective Order

(which has not in every case been done), there would remain, in rich hauls from 100 fathoms particularly,

specimens tangled together in clots from which they can only be freed by tearing them. In such hauls

the error in minute specimens may perhaps be as much as 10 per cent.t; in the poorer hauls it drops

proportionately, till it becomes zero. But I believe the approximation to accuracy to be close enough

to allow one to handle the resulting statistics of population (compare Methods and Data, p. 7, supra),

and in any case the conclusions based on counted specimens can only be put forward provisionally for

confirmation or refutation by future observers.

The hauls used for statistics may be regarded as fairly comparable, except for the varying rate of the

ship’s drift: for this factor no proper correction can be made. Hauls made with a small-mouthed net

of 180 meshes per linear inch have been neglected, as in the case of Chetognatha, because the catching-

power was obviously so slight (simultaneously, 180 meshes caught none, 60 meshes caught 68 specimens ;

180 meshes caught none, 60 meshes caught 10 specimens). Hauls with a net of about 18 meshes per

linear inch, and a diagonal of the mesh-aperture about 1°5 mm., have also been omitted (but not in the

case of the larger Cheetognatha), as allowing small specimens to slip through.

In the course of the second day’s work (July 8) we struck a “swarm” of Doliolum, a

remarkable feature of which was that, unlike the swarms of gonozooids hitherto described,

* Vide Chart, Pl. 9. >

+ Mr. J. J. Lister, testing this in Hastigerina, found in rich hauls an error in my sorting of 5 to 6 per cent.

94. DR. G. H. FOWLER—BISCAYAN PLANKTON:

it consisted almost entirely of blastozooids. For example, haul 214% at 100 fathoms

yielded the following determinable and measurable specimens * in half an hour :—

Blastozooids: 2mm. andlessinlength . . . . . 9869

3 be % ices ai <lMeAd

4 5; r 16

5 % 3 a Gy eee pu)

6 ” 9 se eso, ee gor TO)

i op 5 4.

9 > 5 1

Gonozooids: 2 Pe 35 2

3 1

This puzzling appearance of numerous specimens of the same generation termed a

“swarm ” has been discussed at some length by Dr. Borgert. He refers the swarming to

the more or less seasonal occurrence of optimal conditions, such as food and temperature

(op. cit. pp. 61-68) ; but he rejects (op. cit. pp. 49, 50) the idea that species of Doliolum

have regularly recurrent periods of reproduction, on the following grounds :—(1) that all

the eggs of the gonozooid do not ripen simultaneously, and therefore the resulting blasto-

zooids will be of different ages and sizes; (2) that the blastozooids and phorozooids are

productive for a considerable time, and their successive “progeny” therefore will

be even more markedly of different sizes and ages: thus the effect of a swarm produced

under optimal conditions will be dissipated and untraceable in the course of a complete

cycle of reproduction.

On the other hand, the presence of such large numbers of minute blastozooids as were

taken on July 8 certainly seems to me to demand the pre-existence of a “swarm” of

eonozooids, since the ovary of the specimens examined contained generally only one

large ovum, although plenty of smaller ova.

The swarm was apparently confined to a small space; on the next day, July 9, at

a distance varying from 8 to 20 miles away ina N.W. direction, it was not certainly

recognizable. On July 11 we were again 8 miles from the original position, this time

a little N. of E.; the average catch per haul that day was 2°6 instead of 314, On

July 12, 9 miles S.E. of the original position, the average catch + per haul was 4°5.

Yet the whole area covered by our stations was so small that the conditions of food

and temperature were presumably uniform throughout, and, if optimal at one point,

ought, on Dr. Borgert’s theory, to have affected the whole area, and to have produced a

uniform swarming: this was obviously not the case.

But though the “swarm” was apparently local, yet sporadic sexual reproduction —

appeared to have taken place simultaneously over, at any rate, a large part of the area

under observation. This would appear from the following table { :—

* Actual numbers, not multiplied by a time-factor.

+ The daily average catches per haul have been plotted on the chart of positions, but yielded no obvious result.

+ Days of 24 hours, midnight to midnight. The specimens were roughly measured as 2 mm. or less; 3 mm. or

less, but more than 2; 4 mm. or less, but more than 3, &c.; and the average length struck on these measurements.

They seem to show the comparative daily lengths, but would not be accurate enough to determine (say) rate

of growth.

THE THALIACEA. 95

After this there was a break of five days in the observations, due to deep-water work

and to our running into Brest for coal; except on the 19th and 20th we caught few

specimens, and the figures, both of average specimens per haul per day and of average

and actual lengths per day, are orderless. That sporadic sexual reproduction had

occurred subsequently to the first ‘‘swarm” is, however, seen from the fact that

specimens of 2 mm. and less were caught (for the last time) on the 19th.

We may conclude from the above: that a swarm of blastozooids may be formed, as

well as a swarm of gonozooids; that it seems to demand the previous occurrence of

a swarm of gonozooids; that some further explanation of the production of the swarm

is required than mere optimal conditions of food and temperature, because the swarm is

so local, even when sporadic reproduction is going on in the surrounding area.

I had hoped that these blastozooids were present in sufficient numbers and occurred

on sufficient occasions to enable a test to be made of their reaction to light by the

method used for Sagitta serratodentata (Part III. pp. 60-61, above). But the attempts

at this were invalidated by the presence of the “ swarm,” which sent up the values of the

depths (50 and 100 fathoms) at which it occurred in a manner quite disproportionate to

those obtained for the remainder of the cruise. For example, the average specimens *

per hour haul at 100 fathoms between 3.0 a.m. and 7.0 P.M. were 93°5 if the swarm-haul

21 h was included, but 3:2 if it was omitted! I therefore separated the swarm-hauls

21e to 217, and although they by themselves seemed to indicate a movement of the

swarm to the surface at night, yet the placing of the remaining hauls on day-and-night

tables gave no satisfactory result: it neither confirmed nor denied any vertical oscillation,

either because both specimens and observations were too few, or, more probably,

because no such vertical oscillation exists in this species. But the contrasting of hauls

in dry weather, irrespective of time of day, with those made during or after rain

* Tn this section the actual numbers caught have been treated with the time-factor; nets 18 and 180 omitted:

and averages struck oyer all hauls, not merely those in which the blastozooid occurred.

Average length Length of 1 pebe of

Day. of specimens. smallest specimens, “7750S” BumbDer

(mm.) | (mm.) of specimens.

(mm.)

Talyaee Geese 23 | 2-0 2-0

/ | AS reg

OR ee a, | 2:8 2:0 2-0 S% oS 45s

| Q/> zea <a\eP

NOM ree sae is: +8 2-0 2-0 =e

| wi| LIBRARY

iC ea eae ie 55 3-0 5-0 Zz

12 oth cin as oe 56 +0 5-0

aia Gn oats 6-2 4:0 7:0

96 DR. G. H. FOWLER—BISCAYAN PLANKTON:

markedly showed much the same avoidance of the surface as was noticeable with Sagifta

serratodentata (p. 61, supra). Both sets of figures include day and night hauls; the

swarm-hauls 21 e to h (217% was with net 18) are also included :—

ase 5 ‘ \

At 0 10 hs 94 eee 3) Ba O1n

ca | eae = | Pa oat

a5 | -& Oa OG IN Mets 8 | ese if ai

n Hodes ~ | no) a oO

: c \ ga & Dn \ = Sos

50 | S 10 See LOA) a 3) ee ens 22:0)

i “m6 4 = | GE fey oO

yA r=) oo 5 9). =| o : vo

(es) = 10 2 e 28 oe Wo |) as Se 3:0 a.

S an Oo ao o

a) aS oS ‘ . Baar ee a

100 19 / & 49:3 ee, Ss 70 /

Were the swarm-hauls omitted, the dry-weather values for 0, 50, and 100 fathoms

would be 10:4, 6°8, and 2°1; and the contrast would be even more marked.

In the following table the swarm-hauls have been omitted, in order to get an idea of

the vertical distribution of these blastozooids irrespective of swarms :—

At) BOE gee 41 » 12 A 78 Ee

= one eal i=} © fe)

25 | 3 pion ahora wl S 23 a

rs ze o

50.) yo 2 yen 8B Ma /B aes) lore o

Ss [S) 5 a0 m2 _-

Wor dike: 2 72 s 11 = 2°8 ao

} 30 . Py S |

100 / & 55 20 / 4 2-6 «

Both percentages of hauls and average specimens per hour indicated that 50 fathoms

was the optimal horizon *.

Average lengths per depth, when tabled, did not show that older specimens sought a

different level from the younger specimens.

We may summarize the foregoing paragraphs as follows:—The captures, as a whole,

yielded no evidence for or against a day and night oscillation; but they markedly

indicated an avoidance of the surface during or after rain, the species becoming most

plentiful at 25 and 50 fathoms; the average expectation of specimens is highest at

50 fathoms, which may be taken to have been the optimal horizon for the date and

area studied.

In epiplankton hauls at or above 100 fathoms these blastozooids occurred in 65 per

cent. of the total hauls; below 100 fathoms they vanished; on three occasions only —

(cf. Table, pp. 100-101) there were taken in the mesoplankton net from considerable —

depths fragments of very large specimens of a blastozooid, mostly larger than any of

the epiplankton specimens. These may have been dead specimens of Blastozooid A,

or may even possibly belong to a deep-water species. But there can be no doubt that

Blastozooid A is epiplanktonic.

* It is curions that, on whatever principles such statistics are arranged, the average specimens at 50 fathoms

always have much higher values than at 75 and 25 fathoms. ‘The same was observed in Sagitta serratodentata.

;

THE THALIACEA. 97

Buastrozoorp B.

A single specimen, which had completely degenerated and was in very bad condition,

exhibited muscle-bands thinner than in those attributed to Zréfonis at a corresponding

length. It would not have been recorded here, but for the fact that it occurred in the

same haul as some trophozooids to be described (p. 98).

Doxtiotum Krouni, Herdman.

Specimens which seemed to agree with Borgert’s figures and description occurred in

32 h (50 fm., 1 specimen) and 34.¢ (75 fm., 3 specimens).

As all blastozooids are so much alike after degeneration (which in Blastozooid A sets in generally

at about 2°50 or 2:75 mm. of total length), it is a little difficult to see what criterion can ever be applied

to their specific determination, the organs ordinarily used in diagnosis having disappeared. As an

experiment in this direction, which I hope may be repeated by someone else in another species, I have

measured the width of the fourth muscle-band in fifty specimens of various lengths, and give in the

following table the means (not averaged) at those lengths :—

Mean width of muscle-

Total length. band iv in p.

siormmore, less than 40mm. . . = ya. 270

4 i, i Sy +) 3) haa 502

5 = - Gas i oo tr 575

6 rp _ Wn «ty ee 810

aha dest VONK, Ta ee ep

SHANCMUNOLC Ee Ai eal Us +. «) ~) (gt cue LO

d. Trophozooids.

Trorxozooip A (? = Dottotum Trrronis, Herdman). (PI. 8. figs. 2, 3.)

In 8 out of the 50 hauls between 100 fathoms and the surface, which contained

Doliolum of any kind, occurred an undescribed but characteristic trophozooid, amounting

to 106 specimens. It is stated that trophozooids are unable to lead an independent

existence ; we may therefore expect to find the corresponding blastozooid in

the collection. The mere numbers captured indicate a very great probability that

this form belongs to the Blastozooid A, which I have provisionally assigned to

Tritonis.

The only trophozooids hitherto figured and described with any approach to specific

certainty are those of Miélleri, Krohn, Ehrenbergi, Uljanin non Krohn, and denticulatun,

Quoy and Gaimard. At the outset we are met by the difficulty that the figures of the

trophozooid of Milleri given by Grobben (pl. ii. fig. 9) and Uljanin (pl. xi. fig. 9) do not

SECOND SERIES.—ZOOLOGY, VOL. X. 16

agree together; and I incline to doubt that they are really of the same species: in the

DR. G. H. FOWLER—BISCAYAN PLANKTON:

synoptic table below * I have kept them separate from one another :—

denticulatum

[Grobben ].

Milleri

{Grobben ].

Milleri

[ U]janin j.

Ehrenbergi

[| Uljanin].

Trophozooid A

(? = Tritonis)

[G. H. F.].

Trophozooid B

[Ge He r.j:

Intestine.

widely apart

from stomach.

fairly close to

stomach,

fairly close to

stomach.

widely apart

from stomach.

tightly coiled

with stom. and

cesoph.

fairly close to

stomach.

Anus.

anterior to

cesophagus,

posterior to

cesophagus.

on level with

cesophagus.

posterior to

cesophagus.

anterior to

cesophagus.

posterior to

cesophagus.

Endostyle.

short, posterior, on level

with stomach.

short, far posterior,

behind stomach.

fairly long, from level of

cesophagus to that of

stomach.

long, from well in front

of cesophagus to behind

stomach,

short, posterior, on level

with stomach.

long, from far in front

of cesophagus to well

behind stomach.

These Trophozooids A, which I refer provisionally to 7ritonis, differ in one point or

another from all those yet described, notably and from all in the fact that the whole

alimentary canal is tightly compressed together, almost like a Sa/pa “nucleus.” Many

of the specimens were in very good condition, and the points of difference are therefore

not likely to be due to preservation.

As regards the scale-like projections figured by both Grobben and Uljanin, some of my specimens had

two, some one, some none. It is probable that they belong rather to the dorsal outgrowth of the

blastozooid than to the trophozooid, and that their presence, like the length of the stalk, depends on-

liow and where the trophozooid is broken off. The specimen in Pl. 8. fig. 2 had no scale, that in fig. 3

showed two, folded over: they react to hematoxylin like the test. The long sense-processes figured by

Grobben had generally been knocked off, but were observed in some specimens,

TropHozooip B. (PI. 8. figs. 4, 5.)

In 8 out of the 50 hauls between 100 fathoms and the surface occurred trophozooids

of another character—in all four specimens. In only one of these hauls was there

caught a blastozooid + not obviously like Blastozooid A; this has already been mentioned

in Blastozooid B (p. 97).

* As with the blastozooid, the authority for the description and figure has been enclosed in square brackets.

t+ Of course, the presence of these trophozooids, although only 3:6 p.c. of the total number, renders less assured

my reference to Tritonis of all the 917 blastozooids quoted as A. But if this reference be not accepted, the non-

degenerate specimens can be quoted simply as Blastozooid A, the rest over 3 mm. left doubtful; and the remarks

about swarming, reaction to rain, optimal horizon, &c., can be taken to refer to blastozooids as a whole irrespective

of species, since they omit only 5 specimens,

THE THALIACEA. 99

ii, THE HEMIMYARIA.

This group presented no features of great interest, unless the scarcity of its repre-

sentatives be reckoned as such. So far as the captures go, they confirm the conclusion

of Apstein * that Salpe do not extend deeper than about 218 fathoms (400 metres), as

the lowest haul with the closing-net which contained Salpe was 35 0, 250-150 fathoms.

At no horizon were they plentiful; only 29 specimens were distributed over 15 hauls.

The occurrences sre noted in the General Table (pp. 100-101).

The species captured were :—

SALPA RUNCINATA-FUSIFORMIS, Cham. Cuv.

Of these there were eight gregate, one solitaria.

SALPA ECHINATA, Herdman (? fusiformis, var. echinata, Apstein).

Two specimens were taken, by which the distribution of the species is considerably

extended northward.

SALPA DEMOCRATICA-MUCRONATA ?, Forskal.

Eighteen badly damaged specimens were perhaps referable to the gregata form of this

species.

In the following General Table of Distribution the first three hauls are those made

with the closing-trawl.

The letters have the following significance :—

B = Blastozooid. P = Phorozooid.

G = Gonozooid. So = Solitaria.

Gr = Gregata. T = Trophozooid.

* (©, Apstein: ‘ Die Thaliacea der Plankton-Expedition.—B, Vertheilung der Salpen,’ p. 49,

100 DR. G. H. FOWLER—BISCAYAN PLANKTON :

Depth in

fathoms. Haul.

Tritonis.

Nationalis.

Krohni.

sp., Borgert.

Salpa runcinata

fusiformis.

S. echinata

Doliolum

Doliolum —

Doliolum

democratica-

mucronata?

500—250 29a

1500 —750 30a

2000—1000 30e

0 2le

trd

m0)

ro)

Be WWW

rag

)

ice]

Lao]

te]

50—0O 219

go 92

La-}la>]

nikki habe

THE THALIACEKA. 101

Depth in

fathoms.

mucronata ?

Nationalis.

sp., Borgert.

fusiformis.

Tritonis.

Krohni.

S. democratica-

Doliohim

Salpa runcinata-

| S. echinata.

Doliolum

Q | Doliclim

ine]

ie]

[op]

ae]

lexus Hoo}los|lerhes)leelosorhoxjexhee)ex)

aon

leoles)

150-0 | 86 ol. aan | |

150—50 Be Rees a ce Gr

150—100 21n | |

200—0 Da

200—100 216

250—0 36 h we ». ae oie 5 ee ree Gr

250-150 350 yee aah! xs ae | ae face Gr

300—0 36%

800— 200 Qle eo feed esate Bek 12

350—0 361 DEoe ae ees Stock G

400—300 21k

35 k G50 Sa ac PRGA mss 2 Ue

500—400 21m AbnG Sage ore othe Ite

750—A00 226

1000—750 23a

81d | ?B P

32k ?B

1250—1000 24a

1500-1250 | 25 F |

~ 2000—1500

ait ae ; re

‘

F ‘

i -

> +

ie Sy

POs

BISCAYAN PRANK TO N-

Part V.—THE SCHIZOPODA.

By i. W. L. Hour and W. M. Tarrersatt, B.Sc.

(With Text-figure.)

With an APPENDIX.

By G. HERBERT Fow er, B.A., Ph.D., F.L.S., F.Z.S.

Read 4th May, 1905.

TABLE OF CONTENTS.

Page

UAT CUMOTON a4 45.455 Sib 66 OS GEE 6 SINS OS CO eee Ree emer OP A eer tro ee 104

List of Species.

Division E UC A RID A, Calman*.

Order EUPHAUSIACEA, Boas.

Family Evenavsupx, Dana.

Subfamily Eurnavsin», H. & T.

i, Done, Jive Peasssseeose He Mullente: Claus ta sa2 ch 3 cosas os ere 106

2. Thysanopoda, M.-Hdw. ........ 2. microphthalma?, G. 0. Sars ...... 106

3. Meganyctiphanes, H. & 7’. Sa HORyVeriGd (Ml. SATB) ee oy. s sisian eve 106

Subfamily Nemaroscerin», H. & T.

4. Thysanoéssa, Brandt .......... Ar Overarian Ge OM SGrSia. sacs emis sues 106

5. Nematoscelis, G, O. Sars ...... Ome MOP AOPNs GeOASANS: fairs aialeleialeleis 106

6. Nematobrachion, Calman ...... Ge hoopisi( Calman)! ae aes ee sc inses 107

7. Stylocheiron, G. O. Sars ...... Merb MMe Ge OU Sars? «2.1 viee 6 sore te 107

8. abbreviatum, G. O. Sars ..........- 107

Subfamily Benruzvrnavsin», H. & T.

8. Bentheuphausia, G. 0. Sars .... 5), Wits 6 oeoeet subeosteeaods coodes 107

| Division PERACA RIDA, Calman.

Order MYSIDACEA, Boas.

Family Evcorip2x, Dana.

. 9. Eucopia, Dana .........0..4% 10. unguiculata (Will.-Suhm) ........ 107

Family Mysipx, Dana.

Subfamily Lerromysrn.m, Norman.

10. Euchetomera, G. O. Sars ...... TL SIN Gla, Je Ole el be Io r 104

Changes in the Vertical Distribution within Twenty-four Hours ..............0. 00 eee ce eee eee 108

EME UAU ER CMAR ALE AOLOTD) DIS tI tlOMN: Fe: + «a isrstois a wicivielld ew cls neldepciec decsderveccccecee dein 110

Jodie TP Solls, GLO clan Ci 00) EAS bets 6 cienG GeRRIERE I faci Oc OOD Nic CAL SCIGY oes ene OCLC Cree 112

Pea EMAL AEM OT LCI acy oo oss ci eid, nia's: sna << Aa MIEN A qattsihe aces see ens owes wialem ime Rats 114

Time-Depth Tables, showing Captures arranged by Hours and Depths.............. 0-00. eeeeee 118

PMS Mean IMME Vance leet acitia (avs ste’ s/s» cd eickeis es Masia tae Sinise ass dv ews ccceen cvendem alae 122

* See Calman, Ann. & Mag. Nat. Hist. ser. 7, vol. xiii. Feb. 1904, on “ Classification of Malacostraca,” where it

is proposed to divide the Malacostraca into three divisions: Eucarida, Peracarida, and Hoplocarida.

SECOND SERIES.—ZOOLOGY, VOL. X. 18

104 MESSRS. E. W. L. HOLT AND W. M. TATTERSALL—BISCAYAN PLANKTON:

We have examined the whole of the Schizopods collected by Dr. Fowler, who has

attempted to sort out every specimen from even the largest gatherings, for fear that our

preliminary results, based upon samples, might not truly express the facts of vertical

distribution. We found, however, that the conclusions deduced from examination of the

material taken from the first half of a large gathering were not disturbed by the over-

haul of the remainder, and imagine that this will probably hold good for other plankton

collections, except in regard to organisms which are so small that their distribution in

store-bottles is determined by considerations of ‘gravity.

The collection naturally included a large number of ova and larve, the distribution of

which is of undoubted importance, but in this communication we name only the

larvee of a few species which happen to be absolutely determinable. The remainder

are reserved for a further note, in which, with the aid of a large collection from the

West of Ireland (a region practically identical in specific Schizopod fauna with the

Biscayan region), we hope to be able to add materially to the knowledge of the young

stages.

Our report deals, therefore, only with specimens which have or have nearly assumed

the adult form, or which, if larval, are exempt from the possibility of confusion with the

larvee of species other than those to which we have assigned them.

When the collection was placed in our hands, we were engaged in the study of similar

forms taken from deep water off the West Coast of Ireland, and, with Dr. Fowler’s

permission, we have included in the Irish paper * such systematic notice as was required

by the Biscay material, with some general remarks on the horizontal and vertical

distribution of all the species determined.

Only one form, a Mysid of the genus Hwchetomera, is new to science. We have

named it in honour of its discoverer, and, as appears from the figure, it is rather closely

allied to #. tenuis, G. O. Sars, from the 8S. Pacific. Its range as at present known

includes Bay of Biscay (‘ Research’), W. of Ireland (‘ Helga’), Atlantic 31° 06’ N.,

24° 06' 45" W. (Hansen), and Mediterranean (as H. tenws, Lo Bianco).

For general convenience, we reprint here our diagnosis of the species :—

Evucu2£tomers Fowxenrt, Holt & Tattersallt. (Text-figure.)

Form slender. Integuments thin and diaphanous. Carapace with the anterior margin

forming a very obtuse angle in the rostral region, its apex considerably posterior to the

origin of the peduncles of the eyes ; its posterior margin not deeply emarginate. yes

large, closeiy apposed, sub-rhomboidal and slightly bilobate, their functional facets

confined to an anterior part with long retinal elements, and a postero-lateral part with

short retinal elements; these parts deeply pigmented, the pigment dark brown after

preservation, the remainder of the eye being pale brown, with facets vestigial and

probably functionless. Antennular peduncle with the basal joint about one and a half

times as long as the eye, distal joint as long as the two preceding; male appendage

* « Schizopodous Crustacea from the North-Hast Atlantic Slope.” Report of Sea and Inland Fisheries, Ireland,

for 1902 and 1903, pt. ii. Appendix No. IV.

+ Ibid. p. 123, pl. xxiv. figs. 1-3.

THE SCHIZOPODA.

densely setose in the adult; internal flagellum

very long, the proximal joints remarkably setose.

Antennal peduncle nearly as long as antennular

peduncle, its last joint shorter than the preceding.

Antennal scale slightly curved, about five times as

long as broad, extending for about one-seventh of

its length beyond the antennular peduncle ; external

margin entire, terminating in a very feeble spine;

apex obliquely truncate, extending beyond the spine.

Thoracie limbs in the male with well-developed

exopodites, the basal part terminating in a minute

spine ; flagelliform part with eleven joints, and, in

the last three pairs of limbs, of about five-sixths

of the length of the carapace. Pleon somewhat

narrower than the carapace, with the first five seg-

ments subequal, the sixth considerably longer than

the two preceding segments. TYelson short, its lateral

margins slightly arcuate and unarmed ; apex slightly

arcuate, its exterior angles armed with two closely-

set short slender spines; median setz not closely

apposed, somewhat less distant from each other

than from the angular spines. Outer wropods,

including basal articulation, about once and a half

times as long as the sixth segment of pleon; narrow,

with the apices obliquely truncate and hardly at

all rounded ; setee somewhat widely separate, about

eleven on the outer margin. nner wropods con-

siderably shorter than outer; otocyst very large,

extending to or beyond the extremity of the telson ;

distal part narrow, the apex rounded ; no spines on

the inferior surface ; no denticulations on the inner

edge.

Length of adult male and female 9 mm.

EH. Fowleri is very closely allied to 2. tenuis,

described by Sars from the 8. Pacific off Chili. It

is, however, readily distinguished by three charac-

ters :—(i.) the eyes have no dark pigment except at

the anterior and postero-lateral functional parts;

(ii.) the rostrum, if it can so be called, is much more

obtuse in #. Fowleri; (iii.) the telson has two dis-

tinct, if minute, spines at each angle, and the

_ sete arise at a considerable distance from each

me other.

Euchetomera Fowleri, Holt & Tatt.

(The armature of the telson is not shown.)

18*

106 MESSRS. E. W. L. HOLT AND W. M. TATTERSALL—BISCAYAN PLANKTON;

Evenavusta Mtiiert, Claus.

Hansen, in the later of his papers referred to below has shown that this species is

apparently confined to the Atlantic and Mediterranean.

THYSANOPODA MICROPHTHALMA P, G. O. Sars.

Sargasso Sea and Tropical Atlantic (‘ Challenger’); Indian Ocean (Wood-Mason &

Alcock); Trminger Sea, off Greenland (Ortmann) ; Faroe Channel (Fowler); Bay of

Biscay (H. §> 7.).

The geographical range of this species is therefore considerable, but the records are

isolated and many gaps exist. With regard to the records of this form by Ortmann and

Fowler, it may be noted that the former points out some differences between his

specimens and Sars’s descriptions and figures. Fowler, whose examples from the Faroe

Channel agreed with those described by Ortmann, doubts the identity of the form

with Sars’s species. The larvee from the Bay of Biscay which we have referred to

T. microphthalma, G. O. Sars, contribute nothing to the solution of this point, since they

are not far enough advanced in development.

MEGANYCTIPHANES NORVEGICA (M. Sars).

This species is known from the temperate and Arctic waters of the Atlantic Ocean

and the Mediterranean, and its distribution has been completely traced from Portugal,

by way of the Atlantic coasts of Europe, across the Arctic Ocean to the Atlantic

coasts of North America. From the intermediate waters between Europe and America

it has not yet been recorded. This distribution is somewhat curious and tends to prove

that IZ. norvegica, though often going far from land, is not a truly oceanic form. It is

probably confined to the upper waters of the ocean, at least near its most seaward

limits.

THYSANOESSA GREGARIA, G. O. Sars.

The collection includes some specimens of Thysanoéssa gregaria, a species to which

may belong, as we suspect, some mangled Biscayan examples which Caullery

(«Campagne du Caudan,” Ann. Univ. Lyon, 1896) has referred to the northern and

littoral (or sub-littoral) 7. neglecta.

T. gregaria seems to have an exceeding wide geographical range. It has been

recorded from the North, Equatorial, and South Atlantic, Mediterranean, Pacific from

Japan to the coasts of Australia, but some of the material, including possibly our own,

may prove to be referable to 7. parva (Hansen, op. cit. p. 25).

NEMATOSCELIS MEGALOPS, G. O. Sars.

Off Nova Scotia and Buenos Ayres (‘ Challenger’); coasts of Great Britain and

Ireland (Norman, and H. § T.); Bay of Biscay (H. & T.); seas off Greenland and

Labrador (Ortmann).

This is a truly oceanic form confined to the tropical and temperate waters of the

Atlantic and occasionally penetrating to the Arctic seas.

————— ee

THE SCHIZOPODA., 107

NEMATOBRACHION BOOPIS (Calman) *,

This Euphausian, of which eight specimens were taken by the ‘ Research,’ was

previously known from a single specimen only. The record suggests that it is not a

denizen of the surface.

It has as yet only been met with in the Hastern part of the North Atlantic (see Holt &

Tattersall, op. cit. p. 140; and Hansen, Bull. Mus. Océan. Monaco, xxx. 1905, p. 29).

STYLOCHETRON Suumitt, G. O. Sars.

Widely distributed over the North and South Atlantic Ocean and the Mediterranean,

though not extending into Arctic waters. It is an oceanic form confined to the upper

strata of the oceans. We follow Hansen (op. cit. p. 30) in regarding S. longicorne and

S. mastigophorum as synonyms.

STYLOCHEIRON ABBREVIATUM, G. O. Sars.

West Coast of Ireland, Bay of Biscay; Mediterranean; South Atlantic and Pacific

Oceans. 8. chelifer, Chun, is a synonym.

BENTHEUPHAUSIA Sp.

A specimen of Bentheuphausia is, unfortunately, too small and too fragmentary to

allow us to positively assign it toa species, but we suppose it is referable to the only

known representative of the genus, B. amblyops, G. O. Sars, which has been taken in

the Bay of Biscay by the Prince of Monaco f.

B. amblyops has been met with in widely separated localities, namely, the Tropical

and Southern Atlantic, in the seas to the south of Australia (‘ Challenger’), in the Indian

Ocean (Alcock), and in the Bay of Biscay. The range of the species is therefore

enormous, and it will doubtless be met with in the intermediate waters when these

come to be explored.

Evcopia UNGUICULATA (Will.-Suhm).

This seems to be a widely distributed Atlantic form. For its synonymy see Hansen,

Bull. Mus. Océan. Monaco, xlii. 1905, p. 3.

Many of these forms do not add much to our knowledge of horizontal distribution,

but the absence of Thysanoéssa longicaudata (Kroyer) is interesting as indicating that

the southern range of this typically northern form does not generally extend beyond

the latitude of the south of Ireland.

Gnathophausia zoéa, Suhm, taken by the ‘ Travailleur’ and the ‘ Caudan’ in the Bay of

Biscay, and by the ‘ Helga’ on the Irish coast, is not amongst Dr. Fowler’s captures ; but

so large an animal is probably not very numerous in individuals, and may, for anything

we know to the contrary, be rather benthic than planktonic in habit.

The ‘ Research’ gatherings, which are of plankton, naturally throw no light on the

southward and bathymetric extension of the benthic Mysids which we have listed from

the Irish coast.

* Report of Sea and Inland Fisheries, Ireland, for 1902 and 1908, pt. ii. Appendix No, LV, p, 153, pl. xxvi.

+ Bull, Mus, Océan, Monaco, xi, 1904, p. 14, and xxx. 1905, p. 24.

108 MESSRS. E. W. L. HOLT AND W. M. TATTERSALL—BISCAYAN PLANKTON :

CHANGES IN VERTICAL DISTRIBUTION.

The great interest of the ‘ Research’ collection is found in the light which is thrown

upon the changes in vertical distribution during the times of light and darkness. These

changes are sufficiently explained by the tabies which follow.

The first table (pp. 112, 113) simply lists the species, with numbers of individuals taken

at each station. The sizes of individuals are detailed in the second list (pp. 114-117), and

will, we suppose, be considered as material for the ultimate perfection of knowledge

of life-history and growth, and as of some importance in regard to the weight which

should be attached to the capture of an individual in such and such a net at such

and such a depth in daylight or darkness.

The succeeding tables * deal with a period of twenty-four hours, from midnight to

midnight. ‘The upper strata were continuously examined by open nets towed horizontally

at 100, 75, 50, and 25 fathoms, and thence to the surface; and by similar nets worked

actually at the surface. The strata from 400 to 100 fathoms were examined by nets only

in hours of daylight (in July), viz. between 10 a.m. and 7 p.m. An arm-chair critic

would say that the exemption of these strata from examination at night vitiates the

whole observation, but our own experience at sea leads us to wonder how Dr. Fowler

achieved so much in the time. Even under the White Ensign night-work must be

immensely more difficult than work by daylight.

We are dealing with a single group of organisms, and until all groups have been dealt

with it appears prudent to refrain from insisting too strongly on the apparent evidence of

one, If among organisms too feeble to escape any net there be found definite diurnal

vertical movements, the apparent results of the Schizopod gatherings will receive support.

If none such be found, then the absence of night-searching of the strata below 100

fathoms will be considered as requiring serious attention. .

We select as worthy of special consideration the gatherings of Huphausia Miilleri,

Meganyctiphanes norvegica, and Stylocheiron Suhmii, because these three Euphausians

were very frequently taken during the twenty-four hours.

So far as one can judge from structural characters, Huphausia and Meganyctiphanes are

about equally active when of the same size, but Meganyctiphanes is much the larger

(maximum size 40 mm. to 26 mm.) and therefore the more powerful. Apart from its

smaller size Stylocheiron is obviously hampered by the excessive development of some of

its appendages.

Taking the feeblest form, S. Suhmii+, first, and neglecting gatherings below 100

fathoms, we find that it was taken at the surface thrice during the hours of darkness—

10 P.M., 2 A.M., 8 A.M.,—and never in daylight. Between 25 fathoms and the surface it

* In these tables the hauls in which the species occurred are indicated by heavy type.

7 It must be noted that our record of S. Suhmii includes all the larye as well as the adults, which is not

the case with any other species (except S. abbreviatum). The list of sizes shows that larve greatly preponderated

in the upper hauls, though not to the entire exclusion of adults. S. abbreviatum, G. O. Sars, occurred only in

thirteen hauls, of which eleven were made by night. The captures are not sufficiently frequent for safe deduction,

but if, like S. Sulmii, S. abbreviatum is a creature of the upper strata, the much greater size and consequent greater

activity of the latter may explain its immunity from daylight nets.

le a a ae ee eee ee

THE SCHIZOPODA. 109

was taken five times at night—8 p.m., 9 p.m., 12 midnight, 1 a.m., 2 a.m.,—and three

times in daylight—6 a.m.,1P.M., and 6 p.m. Between 50 fathoms and the surface it

occurred in every haul throughout the twenty-four hours, and so also in the 75 and 100

fathoms hauls.

S. Swhmii is known as a creature of the upper strata of the ocean. Apparently its

vertical movements in July were inconsiderable; and, indeed, if we suppose that its

activity was sufficient to enable it to avoid nets visible to its remarkable optical

apparatus (¢f. Chun, Biblioth. Zool. 1888), we have no evidence of any diurnal vertical

movement. However, though such a supposition might not be unreasonable in the

case of adults, we cannot believe that the larvie, which formed the bulk of the night-

catches in superficial strata, could altogether avoid nets fished in daylight in the same

region.

Luphausia Miillert we take to be a much more active form, and one which in July

(e.g. St. 23 a, 1000 to 750 fath.) penetrated to strata lower * than those frequented by

S. Suhmii. During the twenty-four hours it was taken at the surface only in hours

of darkness—viz. 10 p.m., 12 midnight, 24.m., and 3 a.m., six hauls in all. At 25

fathoms to the surface, also, it was only taken at night or at twilight—-viz. at 8 P.m.,

9 P.M., 11 p.M., midnight, 1 aAM.,and 2 a.m. At 50 fathoms to surface it occurs in six

hauls, and at 75 fathoms to surface in seven hauls, all during the hours of darkness. At

100 fathoms to surface it was taken in every haul (nine) in dark or twilight, and only in

three out of thirteen hauls in daylight. There were, as the table shows, numerous hauls

during daylight at the surface, and thereto from 25, 50, and 75 fathoms.

We cannot deduce from the measurement of specimens any constant difference of size

in relation to vertical distribution, and since small specimens were taken at all depths it

seems impossible to assume that the negative results of daylight nettings in the upper

strata are unimportant. It would seem that in July there was only a remnant of full-

grown Lf. pellucida, and we cannot believe that the capture of the young examples which

form the bulk of the gatherings could have been seriously affected by the success of their

endeavour to avoid the net, since such success must have been maintained to the not

profusely illuminated depth of 100 fathoms. In our opinion /. pellucida in July, in the

Bay of Biscay, rises at night and sinks at daylight, but far be it from us to attempt to

state the vertical movements of an individual.

Meganyctiphanes norvegica, of which the individuals, though not full-grown, were all

large in comparison to /. Wiilleri, was never taken in the hours of daylight, and never

even at night, in surface-nets. It occurs three times in nets towed at 25 fathoms and

thence to the surface, four times in nets towed at 50 fathoms, four times in nets towed

at 75 fathoms, and only becomes general in nets towed at 100 fathoms. The horizontal

locus is, as we believe, rather far seaward from its general haunt, but we are here

concerned only with its vertical movements.

Where was Meganyctiphanes during the day? An animal taken in fifteen night-

hauls (as many as forty-two specimens in one haul) cannot have been absent from the

* Compare p. 122.

110 MESSRS. E. W. L. HOLT AND W. M. TATTERSALL—BISCAYAN PLANKTON:

track of nets hauled through the same strata by day, unless it repaired to lower strata,

which does not appear to have been the case, since many day-nettings between 400 and

100 fathoms give no account of it. We suppose that the table demonstrates that the

species is subject to no marked diurnal vertical movement, but is, under such conditions

of locality, season, and weather as obtained during the period of observation, an

inhabitant of the upper hundred fathoms. It would further appear that specimens of

19 to 35 mm. are sufficiently sharp-sighted and active to avoid nets fished in the

daytime, even as deep as 100 fathoms *.

Nematoscelis megalops is the only other species of which the hourly occurrence seems

to be worth reproducing in tabular form. In activity, apart from considerations of

size, we judge it to be intermediate between Stylocheiron and Huphausia. Its visual

apparatus is practically the same as that of the former, but whether such an apparatus

is, for the purpose of escape from nets, more or less effectual than the homogeneous eye

of Euphausia and Meganyctiphanes is purely a matter of conjecture. To us the table

suggests that Nematoscelis is subject to diurnal vertical movement, but we cannot deny

that the comparative immunity of the species from capture at or near the surface in

daylight may have been due to its perception of the approach of nets.

In this connection it may be permissible to advert to a familiar organism, the pelagic

larva of the lobster (Homarus). Observed in an aquarium, or at the surface from the

ship’s side, it appears to be a feeble and helpless creature. Yet, though obviously a

most abundant item in the coastal plankton, it is, as far as our observations go, rare in

tow-nets, and seems to afford an illustration of the ease with which even a slowly-

swimming crustacean can avoid capture.

In regard to Eucopia unguiculata, of which ten specimens were taken, Dr. Fowler’s

nets give the first indication of the vertical distribution. It was certainly taken by the

‘Research’ at least as deep as 750 fath., and at least as near the surface as 200 fath.,

and this is all that can be affirmed from any source of information.

With the specific determination of the material entrusted to us, and with the

discussion of the vertical distribution of species by night and day, our task appears to

be fulfilled. Considerations of temperature, &c., will no doubt be discussed by

Dr. Fowler in the final summary of results, when all organisms detected can be treated

together. |

Taken by themselves, the Schizopod gatherings appear to give no very important

results in regard to the influence of temperature on distribution. Stylocheiron Suhmii

and S. abbreviatum, which are not known as Boreal forms, occur only in the strata which

reach 52° F. (11° C.) or more ; but Meganyctiphanes, which is a Boreal and Arctic form,

and must endure much lower temperatures in the northward part of its range, was

apparently confined to the same strata. Mematoscelis megalops, also a Boreal form, was

* We write only of the ‘ Research’ results. The species certainly occurs at the surface, or quite near it, at

night off the west of Ireland, and has been cast ashore in quantity on the North coast. In the Irish Sea, which is —

shallow, it is common at inconsiderable depths. Though it is taken far to sea in the upper strata of very deep

water, we do not regard it as a truly oceanic form (cf. H, & T., op. cit.).

lS it a pa i ea tt, pe a

THE SCHIZOPODA, 111

not taken in water colder than 46° F. (8° C. ea.), and occurred in water of 63° F.

(17° C. ca.). The temperature range of Huphausia Miilleri, not Boreal, was about the

same.

Other species were not taken in sufficient abundance or in sufficiently defined strata

to afford absolute evidence.

Dr. Fowler has called our attention to the remarkable abundance of specimens in

haul 310, and proposes, we understand, to advert to it in his own analysis of results

(p. 122). We note it here merely as an illustration of the difficulty of assigning, in

attempts to take a census of Plankton, its true value to the catch of each net. Close

inshore, every collector knows that by hauling a net through a seam of tide the catch

will often be infinitely greater than that of hauls made even a few yards on either side

of the seam. Further to sea, but still within the littoral area, similar experiences of

quantitative difference of catch within comparatively small areas not defined by any

obvious physical phenomena are by no means unfamiliar. Here we have an oceanic

instance, to which we would invite the serious attention of any who may be disposed to

regard the solution of marine bionomical problems as capable of absolute mathematical

solution.

[In the following General Table of Distribution (pp. 112-113), the first three hauls

refer to the Mesoplankton Trawl, the remainder to ‘‘ comparable” hauls * (supra, p. 5).

In the genus Stylocheiron, where every larva has been as far as possible identified, the

numbers before a + sign indicate the adults, those after it the larvee. In thé remaining

cases, the younger larvee have not yet been completely worked out (p. 104), and only

conspicuously identifiable larvee have been recorded by an L.—G. H. F.]

* 21a, made with a closing-net pulled up directly to the surface, should have been classed as “ non-comparable.”

The following were the captures of the “‘ non-comparable ” hauls :—

21d: 100-0 fathoms: 1 Stylochetron Suhmii.

27a and a’: 1250-0 fathoms; 2 Lucopia unguiculata, 1 Bentheuphausia sp., 1 Nematobrachion bodpis, 5 Stylo-

cheiron Suhmii, 6 Euphausia Miilleri.

SECOND SERIES.— ZOOLOGY, VOL. X. 19

112

MESSRS. E. W. L. HOLT AND W. M.

TATTERSALL—BISCAYAN PLANKTON:

Depth in

fathoms.

500—250

1500—750

2000—1000

—$_—————

25—0

50—0

75—0

hthalma?

Miilleri.

| Thysanopoda

microp:

| Euphausia

on: o

norvegica.

gregaria.

| Meganyctiphanes

Thysanoéssa

2 oy iiog

Nematoscelis

megalops.

HH:

| Nematobrachion

bodpis.

unguiculata,

Suhmit.

abbreviatum.

Euchetomera

Fowler.

Stylocheiron

| Stylocheiron

Eucopia

042

THE SCHIZOPODA. 1138

S | Ge

er sales - 3 § gis

eee ae Haul. 25 oS £5 os ey S.3 ‘Ss ‘38 ss Ss

SS ose | Se | Ss SS akees) | Se aeeeen | SS ssh -

§ ~ = > q q BR B QR 8

100—0 Qh 542

211 i 041

Qa ES 0:29) 1-20

| 24d ei 3 20 in all! 340

24 d e 1 5+0

Ae a 3 2+0

25d a SEI 347

30g i ~ 242

30h 3L - 4412

32d A 142

B20 oh a Gs Bt oe 147

32 11 1L 8 ib 13 Se Wee | Wei!

32 p ll 1L 25 ee 31 Nese ll) alee

33d fi a - 1 i! 140 | 240

345 5 6 3 19 .. | 6feo | 041

34d 3 14 os) 16-20 5245

35 b 8 1 feck .. |16+0 | 140

35d 4 eae oe Geto) NTN

35 43: ; m9 141

| 35x 3 1 644

36 6 12 4 5 1142

366 ie 842

150—0 36 f OM ae a Bs Pee Ge 245

150—50 21'p See iye cs - we Wal Re 140

150—100 212 | |

200—0 2la 4

369 2 1 38+0 1

200 --100 216 |

2lo F 5 OC 1

26e

34h ; 1

35m 5

35 n if |

35 t

250—0 36h 1 tS Ss AD a u 342 ia a 1

361 12 a nm in ey ie 143

250—150 350 Th

35 p 10 1

358 |

300—0 36k ON tae cue Ve, re uae, 1 142

300—200 Qe Me x ee a ee a 0+3

26 f |

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400—300 21k ea bed e at 5 e: 2

321

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19*

114 MESSRS. E. W. L. HOLT AND W. M. TATTERSALL—BISCAYAN PLANKTON :

Sizes oF INDIVIDUALS.

EvurHavustaA Mixuuert, Claus.

Synon. :. Thysanopoda bidentata, G. O. Sars.

Euphausia pellucida, pars, G. O. Sars.

Euphausia pellucida, Holt & Tattersall.

Fath, 0. 211i ...... 24, 10-15 mm. | Batheel00=0: 210 2...) i LOammnnr

- es MRO So soan lbs (ertiie, * fe 30g .... 1,1 Late Purcilia, 6 mm.

. 55 QDiee meee 2, 7-8 mm. | _ - 302 .... 3,1. Furciha, 5-6 mm.

- _ ENE ee ens fats 15, 6-14 mm. 3 im 32nt .. 11, 5-12 mm:

. By BEG so ee oe 2, 11 mm. | ns - 32p .... 6) 1255 mms

y e oS OW Ani ae ain 1,15 mm. | 5, not measured.

1» SS BO coco bo 4, 5-12 mm. | ns - 83.d .... 7, L0=14mme

se e Pat ATe hance RENCE 9, 12-15 mm. a 3 346 .... 8, LO=(2imme

5 = SB ea acisarks 3, 8-10 mm. 2, not measured.

#5 . BIG] | sole as 15, 8-12 mm. - + 34.0) Jenne elem

34 55 OUNUS toner atnteye 16, 8-10 mm. 2, not measured.

* A SOc eek 7, 10-13 mm. 5 * 356 .... 3, 12-15 mm.

1, 26 mm.* 5, not measured.

3, not measured. . - 35d .... 3, 6-10 mm

5 DO=O%, ULI sc wae 1, 11 mm. 1, not measured.

ze “ S004 cece 32, 8-18 mm. 5; 55 SD...) o,O—Gunms

: 1, 25 mm. 55 5 366 .... 6, LI=l3imme

Fe * SIO? eaters 250 ca., not measured. 7, not measured.

a a3 BAC iat oes | 45 lee omimns » 150-0. 36f .... 2,1. Cyrtopia, 6 mm,

5S son SS Tae dy 12, 8-15 mm. 9200250; 210 ...: 4,750 im

a us SOG i acrasoe 3, 10-12 mm. ss 5 309 ...+ 25) l0kmmy

1, not measured. » 200-100. 35m.... 5, 5-10 mm.

a Gone Beit sand sc 16, 5-14 mm. ms ne 35” .... J, fragment.

s *s 30) obaods 5, 12-14 mm. = 2X00, SHG pam 85 iO secon.

s - SBYOb ¢o.00d0 27, 8-15 mm. | Pe a 367 .... 8, 7-14 mm.

- fe Be a aoiarare 5, 10-13 mm. | 4, not measured.

4, not measured. | » 200-150. 350 .... 1,10 mm.

1, fragmert. - ay 35p .... 10, 8-13 mm.

pe) USa aemmeas 9, 8-12 mm. | ,;, BOO-0eRBGi.... 1, 18imm,

2, not measured. | 1, not measured.

ck 4 BING iG adion 3, 8-12 mm. | » 300-0. 367 .... 2, not measured. y

1, not measured. 3 LOOO=T50R2Scmm... nme

oo, G1 Shae Meee: 5, 10-12 mm. |, 1250-0. 27a.... 6, 9-12 mm.

* This is the largest known example of the species.

t+ Includes n’. '

The larve, ‘‘l,’ mentioned in the above list are only the larger forms which can

easily be referred to this species. The collection comprises a number of small larva —

and ova, probably belonging to £. Miélleri.

THYSANOPODA MICROPHTHALMA ?, G. O. Sars.

Fath. 70-0. ~S2ioy ene. 1,1. Furcilia, 5 mm. Fath. 100-0. 32p ...... 1,1. Cyrtopia, 6mm.

yy LOO=O) (S2inw chee 1,1. Furcilia, 5 mm.

The above are large larvee which have nearly attained the perfect form. Younger

larvee may be present in the collection, but have not yet been determined.

MEGANYCTIPHANES NORVEGICA (M. Sars).

Fath.

thi

THYSANOESSA GREGARIA, G. O. Sars.

Fath. 100-0.

Synon. :

Thysanopoda norvegica, M. Sars.

Nyctiphanes norvegica, G. O. Sars e¢ auct.

Meganyctiphanes norvegica, H. & T.

32 n

4, 19-28 mm.

12, 25-30 mm.

2, 25-27 mm.

2, exuvie, ca. 30 mm.

1, 30 mm.

1, 22 mm.

2, 20-26 mm.

1, exuvie.

20, 22-35 mm.

1, 26 mm.

2, 1. nearly adult.

Fath.

Caullery * has recorded 7. neglecta from 935

record is somewhat remarkable, as the species is otherwise known only as a northern

form, and one which does not appear to range very far from shore nor into water of more

than a few hundred fathoms (compare p. 106).

NEMATOSCELIS MEGALOPS, G. O. Sars.

Fath.

ee i

”

1,10 mm.

1, 24 mm.

1, damaged.

1, 9 mm.

9, 12-17 mm.

3, not measured.

4,10 mm.

1, not measured.

4, 13-18 mm.

2,8 mm.

26, 14-18 mm.

1,1.5 mm.

10, 8 mm.

35, 7-11 mm.

90, 4-8 mm.

4, not measured.

3, 18 mm.

2, not measured.

3, not measured.

5, 5-9 mm.

12, 12-20 mm.

LI:

25, 16-22 mm.

2,14 &17 mm.

THE SCHIZOPODA.

1520, BELO eoec cc

100-0.

SiN) Aarne

1, remains. Exuvie?

7, 24-30 mm.

1, exuvie, ca. 30 mm.

25, 22-30 mm.

1, 24 mm.

9, 23-31 mm.

1, 28 mm.

2, 24 mm.

2, 30 mm.

fathoms in the Bay of Biscay. The

WO-Og GEC sean.

100-0, 246 ......

Ps DAP aise «:«

5 QOD Vets «:s

; Ten eaters! 5

5 OLD owes ss

a Bide ot bak

4 Ce he A

a STACUN ovate at osc

,, RRC ayers viz x

. SA oan oe

4 SHON aes. 2:0

150-50. Qlp......

200-100. 34h ......

S00 50% <.....

400-300. 21hk......

760-500. 226 ......

* «Campagne du Caudan,” Ann. Univ. Lyon, 1896.

15, 15-18 mm.

11, not measured.

3, 9-10 mm.

1, not measured.

Sea,

1,12 mm.

1, 7 mm.

12, 14-16 mm.

31, 14-20 mm.

1, 9 mm.

19, 1]-22 mm.

15, 10-20 mm.

1, not measured.

1, 18 mm.

5, 18 mm.

1, 13 mm.

1, not measured.

1, 25 mm.

3, damaged.

1, 9 mm.

The records of larvxe of this species in the above list are not intended to deny the

presence of other larve of NV. megalops in the collections. Of adult forms there are a

116

few damaged “hulls”? without appendages, which may belong to this or another species

of the Nematosceline subfamily; they are not otherwise mentioned in this paper, as

their specific determination, if it were possible, would not affect the evidence of the

MESSRS. E. W. L. HOLT AND W. M. TATTERSALL—BISCAYAN PLANKTON:

vertical distribution of any of the species to which they might belong.

NEMATOBRACHION BoOPIs (Calman).

Synon.: Nematodactylus bodpis, Calman.

Fath. 100-0. 32p......

Se AUOE0) HOG eo o0nc

PAV0, BGG 5 o5550

”

250-150. 35p ......

”

STYLOCHEIRON SuuHMII, G. O. Sars.

Synon. : S. longicorne, G. O. Sars.

S. mastigophorum, Chun.

Fath. 0 22d 2 2

RP Sn nulie Wa.yaee= lp |

a i Spi saucaK 2, 8 mm. |

5) SSEOS Gil welea ae 3, 5 mm.

a oR ae |

9 55 ORE) ia! sis share Sele

a *5 BOG) co vieie eis is Ih

= 5 BATT Sot avel ee 5, 1.

5 fe GU AGr tig aaarG Peal

2, small, not measured.

& 5 BON Sage tc 3, 1.

+ 5 BOlChee chicas BE

ay O0=0;, s2ilNo Meee tsi Jk

os = DD IBUE xcucee rel 23, 1. |

ee a PID A68500 20, 1.

i 5 25k ...... 22,1.—8 mm.

i ns WANG spe oa.oe 18, 1—6 mm.

+s - Bh St Goce 44, 1.

1, not measured.

- es BO Goce Osa

.s ’ Bly & ooeus LOM

_ 7 SZICes tte 11, dh

1,8 mm.

3 . BLING ween srs 12, 1.

24,6 9mm.

Z os GBM la naas 2, not measured.

241:

’ 9 BB? cb oon del

3, 5-7 mm.

” 9 SOMa wer aiscs 3, 1.

. .23, 5-9 mm.

Bo O=0., O0ifi taeieers 39, 1.

36, 5-9 mm.

” ” BIG Bao. oe 8,1.

2, 5-6 mm.

Fath. 300-0.

”

350-0.

500-250.

1250-0.

”

32m

320

1, not measured,

1, 18 mm.

1, damaged.

30, 1.—12 mm.

oils

28, 4-10 mm.

5, 8-9 mm,

24,1.

30, 4-9 mm.

10, 6-8 mm.

sls

8, 6-8 mm.

Sails

Deal.

5, 6-8 mm.

6,1.

5, 5-8 mm.

1, 7 mm.

7,1.—T7 mm.

ical

Oeie

20, 1.—8 mm.

5, 8 mm.

2,7 mm.

10, 1.—6 mm.

2, 1.

2, 5 mm.

L201

4, 8-10 mm.

als

1,8 mm.

giles

1,8 mm.

20, 1.—10 mm.

enue

35, 4-9 mm.

1, 9 mm.

THE SCHIZOPODA.

I a ee ai ia ie

Wath 100-05 346 2.2... 33, 1.—9 mm. Fath. 150-0.

+ * as oe Sails |

52, 5-8 mm. i 150-50.

; 5 SoiOwtetsois 16, 6-10 mm. es 200-0.

: 3 BEC; Geno on ra A: 250-0.

3, 6-8 mm. |

3 z CO eee ise gas a

1, 11 mm.

> Rs OIG arn 6 ale 10, 1—8 mm. i 300-0.

, cf Stay. Saeorme Pale

11, 5-7 mm. 5 350-0.

. - SGeweeics 2,1. / 300-200.

3, 7-10 mm. i a 1250205

117

SL een 5, 1.

2,8 mm.

Palsy Gao 1,9 mm.

BIO Goons 3,8 mm.

SOO an ates 2, 1.

3, 5-8 mm.

36a se aay

1, 6 mm.

SGU. alates Za, De

1, 8 mm.

SO lentes ies ib

NCP ire crate 3, |

PH ah wee ee 5, 1.—-8 mm.

The above list includes all the larvee in the collection, and in this respect is comparable

only to the list of S. abbreviatum.

STYLOCHEIRON ABBREVIATUM, G. O. Sars.

Synon.: Stylocheiron chelifer, Chun.

Stylocheiron abbreviatum, Ortmann.

Hanh 70-0: S2m ....0..+ Bile Fath. 100-0. 327 ...... il 3h.

4 (l.orsmall, not measured). es As SOD ievatere ier: 1, 18.

ae eee 1, 7:5 mm. 5 i BOG eas 1, 17 mm.

Bre Ob ccarssahe's 1,18 mm 1 (not measured).

# a GHOy es aoe 5, 1. m2 5 BABY Sad 3) ace Ter

a 3 SE) (2s erearneticie 2,10 mm A i BOOKS ela cic 1, 12 mm.

i % ROCs Saseen 1, 10 mm = Pe SOND api aicgeie 1 (not measured),

PeLOO=O5 22a. so... . 1,10 mm

¥ 53 EO fe Secs 2, 6-9 mm.

a Opepe 1, fragment.

All the larvee in the collection are listed above.

The generic characters are apparent

from a very early stage, and specific differentiation from S. Swhmii is easy on account of

the difference in size.

BENTHEUPHAUSIA sp.

Fath. 1250-0. 2 1, damaged, 8 mm.

Evucopia uneurcuratra (Will.-Suhm).

Fath. 200-100. 2lo ...... 1, fragment. Fath. 750-500. 226 ...... 1, 12 mm.

7 350-0. fos eS es 1, 15 mm. 5 1250-0. ATR voc eaters 1, 26 mm.

A, 200-3005 20... <e 2, 14-20 mm. 2h Seer 1, fragment.

e. ee SDK a eiea 1, 15 mm. a 1500-750. 30a ...... 2, 14-20 mm,

EvucH#£roMERA Fow tert, H. & T.

Fath. 200-0. 369 ...... 1, 9 11 mm. | Wath. 250-0. 36A...... 1, 6 10 mm.

Nore ADDED 1N Press.-——The manuscript left our hands before the appearance of

Dr. Hansen's papers, Nos. 30 and 42 of the ‘ Bulletin du Musée Océanographique de

Monaco.’

exigencies of pagination.

Imperfection of reference to these papers must therefore be ascribed to the

MESSRS. E. W. L. HOLT AND W. M. TATTERSALL—BISCAYAN PLANKTON:

118

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BH. W. L. HOLT AND W. M. TATTERSALL—BISCAYAN PLANKTON:

120

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121

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¥ 198 | if [vy B jo y93uay aq} eyBorpur sMoaue osaya qdaoxe ‘syau

| vedo yjIMm aovjans ay} 0} YSno«qy uayy, s—neq [Ly

v ; aaa ¥ 2 : és *

21G |foz 19) yt | | 008 ro)

rf | hi.

ny gee tQ¢ | 498 | } 0&6

Eyal ee | :

| ete f ¥ | | be Pe

y ve aSe qie| wSorzage mS? 298 006

ae rE aT

ab: | wie 39 OST =

| | | | B

23 fe ly yl alice | ly | yvvi 298 [_ deal aN ee DP

USE PEEXSE TIT YOE ITE PVSF0OPHS 11S Ibs 3SE, PTE pPsEerPveaseavedzedge) Ol) |

8GS| PGS °

ee : | pees ee i _|__ote (5 See alee

wge Tee &c¢e 2S JOE 3ce 2GE OVE BCS WEES) a 2

| Some Ur poe! 4 ees Pe es ey A)

10€ Jee 3G 318 are %FE 99% GE ass pg9e ate!

wof | Seg eg Moe | ; pete cay pgz | gok ewe | gee eperge ere %%

bzz | azz me Wit! Mee qSz aee | ybz

Wrz Sz PBS ysoe Bee p fz eae aiz | abe nz | 90 aze 18% Bee 2bz 0

| é

WHE OL 6 8 ZL 9 iS iv

i Ne IE (OE 6 8 L 9 & F Ce OG Le Sal

“00 NT “VU S1UpLyy

122 DR. G. H. FOWLER—BISCAYAN PLANKTON :

APPENDIX ON THE VERTICAL DISTRIBUTION AND MOVEMENT OF THE SCHIZOPODA.

By G. Herpert Fow.er.

[I HAVE added these few notes to the foregoing paper in order to bring the results into

line for comparison with those which are being obtained in other groups of the collection.

In particular, the tables of averages seem to me to be important from the point of view

of the reader, because (for example) although the time-depth tables on pp. 118-121 give

through the eye a general idea of the distribution of a species as regards the upper

strata, they give no idea of the comparative numbers present ; further, the hauls having

been of varying duration and made with nets of varying mesh (both of which were

mistakes), a common standard is required for the real appreciation of their meaning,

certain hauls must be omitted as misleading, and so forth.

EupHavusiA MULLERI.

A reference to the General Table of Distribution (p. 112) shows that this species was

well represented in the Epiplankton, at any rate at certain hours. Below 100 fathoms

it oceurred occasionally in the closing-nets 200-100 and 250-150 fathoms. It was not

taken by any of the 25 hauls which closed below 250 fathoms, with the exception of a

single specimen in 23 a (1000-750 fathoms) ; as it failed between 250 and 750 fathoms,

I venture to differ from Messrs. Holt and Tattersall in thinking that it probably is not

to be found alive much below 250 fathoms *.

The captures with comparable nets are analysed in the following table +, which should

be read as a sentence from left to right :—

0 55 \\ cael

\ Lard

25 50 | Ba 40

= =E

= 50 = © 746: \eeeleeemcel t >

° © || ae <= e

a 75 3 63 = 5 81 ee

6 100 + | 5a Jee Bl Se

oO i =|

= 150 a 1 1-0 = 3,

S = as)

4 200 8 ie 1:0 Eo

Oo aa a

Q a peut a4

5 250 3 2 5 3°5

| 300 i) 1 a 10

let

350 3 1 4 10 “

to me > Qe

B. \200-100. | = ye OS meee &.3

4 FOE s

@ 250-150 5 2 36 Ey B ue

* Its occurrence in 27 a’, and 36f, g, h, i, k, l, being all nets open to the surface, give no reliable indication of

its depth-limits. ; q

+ In this Appendix, some Schizopods have heen treated statistically in the same manner as were the Chetognaths —

of a previous paper. ‘‘ Average specimens ” have been averaged over all hauls, whether the species occurred in them

or not; nine surface-hauls with a mesh of,180 per linear inch have been omitted, as failing to capture strong

swimmers, The actual numbers recorded by Messrs. Holt and Tattersall have been treated where necessary with

a time-factor to bring them to the standard one-hour haul. 4

t The rich haul of 316 (11.30 p.at. to 12.30 a.m.), which also caught an unusual number of Nematoscelis megalops,

a ee ee ee ee eee

THE SCHIZOPODA. 1238

On the question of a vertical oscillation, as Messrs. Holt and Tattersall have already

pointed out (p. 109), the table on p. 118 seems to indicate a nocturnal rise and diurnal

fall of this species. But it seems worth while to present the evidence for this view in

the form of statistical tables in the same manner as has been adopted for Sagitta

serratodentata (p. 60), a case in which the reverse oscillation appeared to hold good *.

The following table shows the average catch per hour haul by “day” and “night”;

the dawn, about 3.0 a.m.,and dusk, about 7 p.m., are the most convenient dividing hours ;

but if 4.0 a.m. be taken instead of 3.0 a..., allowing time for the species to sink after

dawn, the contrast is even more marked, and the method is probably more in accord

with the facts.

4.0 a.m. to 7.0 p.m. 7.0 p.m. to 4.0 a.m.

Depth in a

fathoms. Number of antes Number of BN oe

hauls, P of hauls. ape”

per hour. | per hour.

One ss 9 0 I i 117

| ||

PSR Okie 6 0 | 9-5

OOK es a 8 0-5 4 12-5f

TOS PO 3 0 8 TD

OO; seine 13 0:3 9 72

The arrangement of the captures according to the light-intensity as tested by a

photographer's actinometer, which gave no results in the case of Sagitta serratodentata,

confirms the idea of the oscillation of Miller’, and indicates that the movement affects

the upper 100 fathoms a little before dusk and after dawn. In the next table, which

illustrates this point, the hauls were arranged according as the actinometer assumed the

standard tint at 2”, 3’-6", '7’-10", 11” to dusk or dawn; the remaining hauls being

was evidently made under abnormal circumstances, and sends up the values for 50 fathoms in all the tables to

a disproportionate extent. My log records ‘‘ beginning to blow, some rain” about midnight, and it is barely possible

that the weather concentrated at 50 fathoms specimens which normally would have been at higher levels at that

hour, The number caught was so abnormal that the haul has been omitted from the tables of Z. Miilleri and

NV. megalops, the values obtained by its retention being, however, recorded in footnotes; if included in this table,

the average specimens at 50 fathoms would be 23:3,

* As this species, unlike serratodentata, was only found at the surface at night, and the hauls “ during or after

rain ” were all in daylight, the latter are not shown separately from the rest.

+ If haul 31 } be included, 5 hauls yielded an average of 60:0! The single haul at 50 fathoms which showed

specimens in daylight was 32 a, 4.15 to 5.15 a.m,

124 DR. G. H. FOWLER— BISCAYAN PLANKTON:

grouped as “night”; the numbers at the various depths are average specimens per hour

haul, the absence of observations being indicated by a plus sign :—

Fathoms. 2". 3'-6", 7"-10"" 11” to D. Night.

OM scraeaer 0) 0 0) 0) biley

ZO Rees +f 10) 0) 0) 8:0

DO ae ee: ar 10) 0) 20 13°5 *

Oe | Reece - 0) 0) v2 15°2

LOOMS F.cerr: 0) 06 0) Ae. 86

It is noticeable that a bright moon did not seem to drive the species from the surface

(compare captures at 217, 22g); the average capture per hour in bright moonlight

was 13°53.

The foregoing tables show pretty clearly the oscillation of this species by statistical

methods. The question may pertinently be put,—where was the species to be found

by day? The answer to this unfortunately cannot be deduced with certainty from my

collections.

Three hauls out of thirteen at 100 fathoms between 4.0 a.m. and 7.0 p.m. produced

five specimens, which work out to an average of 0°38 specimens per hour haul: still,

what may have been the upper fringe of the species was at or about 100 fathoms during

the day, so far as my hauls go. :

The seven serial two-hour hauls (86 e, f, g, h, 7, k, 1) only caught 21 specimens among

them (absoiute untreated numbers), giving an average of 1°5 specimens per hour haul,

which is surprisingly low.

But it is noticeable that at 250 fathoms one serial tow-net (36 2) caught as many as 12

specimens (6 per hour), and that the closing-nets 85m and 35p caught respectively 5

and 10 specimens per 100 fathom haul; in other words, these closing-nets produced one —

specimen for every cube of (approximately) 53 feet and 7 feet which they respectively

filtered. This indicates the presence of a fairly large population between 250 and 100

fathoms in daylight.

MEGANYCTIPHANES NORVEGICA.

This species was taken solely at or between 25 and 100 fathoms.

ATS V0) aie 0 | 0) z

Oo e& ae) 32

25° ‘|’ po iewee ceo Meee 50 | 28

QO ot -_ Oo io]

| aes =o ES

50) | "gol awe ee ee oo

c = RO

= jonny E-e Q

rh) |. aoe, BGs eee 41] 8.

Poe EZ Se, = el

100 27 ) Ey ee 8

n 4

It occurred in only 20 per cent. of the total hauls at or between 25 and 100 fathom

Owing to its comparative scarcity, conclusions drawn from its distribution during th

cruise would be unconvincing.

* Tf haul 31 were included, this figure would be 60:0.

THE SCHIZOPODA. 125

The distribution of the species during day and night is shown in the following table

for comparison with the other common species :——

= 4.0 a.m, to 7.0 pat. 7.0 p.m. to 4.0 a.m.

Depth in Average specimens Average epecueeng

fathoms. Number of hauls. per hour haul, Number of hauls. per hour haul.

OD eee gees 9 0 7 0

2D) ee caches 6 0 6 10°1

510) Se staaeaeaaeen 8 (0) 5 48

MOL rae tijientis 3 0) 8 66

TKOLO Me aoqenesnae 13 0) 9 5

As Messrs. Holt and Tattersall point out, the failure to capture @ single specimen

at any depth whatsoever during daylight is most curious, and must be left unexplained

for the present.

NEMATOSCELIS MEGALOPS.

The vertical distribution of this species was apparently very similar to that of

_ Euphausia Willeri.

0 12 5 0:2 2

er J @

25 41 one 19 | @3

— = g =o

= 50 46} “s 66) oa

jo) 3 _ 4. ° = =

— 75 = 45 & tar) 6:2 =e.

=] & + es

fe 100 Le, Pi Vee ves

a 150 3 0 0

5 200 Sy 0 0

iq) R

= | 250 2 0 0

e 5

300 Som Gl © 1 =

350 ° 0 © 0 =

/ = am og

150-50 S 1 2 Ay hae.

5 | 200-100 & 1 = 1 5

s& | 300-200! = 0 0 =

@ 5 / 400-300 | 1 5

B98

a 500-400 0 0

@ / 750-500/ 1 1

_ From this table* it is apparent that the centre of distribution lay about 50 and 75

fathoms; it occurred in only 13 per cent. of the 23 hundred-fathom sections with the

closing-net between 750 and 100 fathoms, with an average of 0°3 specimens per

100 fathoms,

It is possible, as Messrs. Holt and Tattersall suggest, that this species exhibits a

diurnal fall and nocturnal rise like Ewphausia Wiilleri, but neither the time-depth

_* Tf haul 31 6 were included (compare p. 122, note) the average specimens per hour at 50 fathoms would have

been 13:0.

126 DR. G. H. FOWLER—BISCAYAN PLANKTON :

table (p. 120) nor the table of average specimens per hour haul immediately following

shows it so obviously as in the other case.

4.0 a.m. to 7.0 p.m. 7.0 p.m. to 4.0 a.m

Depth in Average specimens Average canine

fathoms. Number of hauls. per hour haul. Number of hauls. per bour haul.

On. dheeaeeee 9 0) 7 05

20). Eeatoneecer 6 (OP 6 3°6

BO. peceseetecea 8 Oe At 18°5 ¢

7D” [etetaceee 3 TEGO 8 8:0

NOO® Eeacseteed 13 0-4: 9 75

The most that one dare say is, that the species was less commonly caught in daylight

than at night.

STYLOCHEIRON SUHMII.

The table below shows that, while the species occurred in every haul at 50, 75, and

100 fathoms, the expectation of specimens was highest at 50 and 75 fathoms.

Oseus 2\ 0-5

¥ 25 A 66 Bo 2-4 ,

5 50 = 100 wie 21°5 g

— = 2

ra oa iS HO 9. — IQ

g 75 E 100 = me 22°6 Eo

& | 100 preg! 0) Bie ads'9 a

+ | 150 a re is, Gt, {eee

2 eet)

a 200 3 1 1a B

= g, cs

2 250 Z 2 = Toa AS ay fe)

300 8 1 | eee Ita aly |

350 a 1 =, Oa. 6.4 / ‘Ss +

te) 150-50 | 1: ae la \ oi ee

oe o2.8

2 ) 200-100 0 ones) =: ms

= ) 300-200 1 lu J Ba ©

The evidence of this table appears to point to this species having been epiplanktonic.

In the open serial nets, I have shown adults (A) and larvee (L), because, as will be seen

from the next table, the expectation of larvee diminishes with depth; and if these larvee

be subtracted as possibly dead and sinking, the remaining adults are not more than

might be expected to be captured in the upward passage of an open net through densely

populated strata. A few specimens may have penetrated beyond the 100-fathom

horizon, but the centre of distribution was doubtless the lower epiplankton between

50 and 100 fathoms.

Omitting the surface hauls, which contained only eight (4 A and 4 L) specimens in all,

captured in two out of sixteen hauls, and are therefore too few to carry any weight in

* Bright daylight, actinometric standard reading 3''-6".

+ If 31 6 were included, 5 hauls at night would yield 32°8 average specimens.

THE SCHIZOPODA. 127

this connection, it appears that the expectation of larvee diminished with depth, that of

adults increased with depth: the average catches per hour haul consisted

At 25 fathoms of 93 per cent. larvee and 6 per cent. adults.

50 2 ” 73 3)

75 ” ” 34 »

The next table presents the distribution of adults, of larve, and of both taken

together, at various depths by ‘“‘day” and “night” (as in previous cases), in average

catches per hour haul. It shows no evidence of a nocturnal rise of the species ; but it

presents some puzzling features.

4.0 a.m. to 7.0 P.M, 7.0 p.m. to 4.0 a.m.

Depth in

fathoms.

Hauls. | Adults. | Larve. | Together. || Hauls. | Adults. | Larvae. | Together.

(0) g 0 0 0 ii 0-5 05 iftslt

25 . 6 0:3 aT 15 6 0:0 3:3 3:3

50. 8 33 21:4 24:8 5 9:6 66 16-2

(ire 3 126 16:6 29°3 8 15:5 4:2 20:0

NGO) vee 13 2-1 3:0 a1 9 22:0 2:3 24:3

One of these is that so many more adults were caught by night than by day at 75 and

100 fathoms—depths at which it is difficult to think that the light is strong enough to

enable the species to see and avoid a net; and a remarkable feature is that these large

night values were mainly due to three hauls (84 8, ¢, d), all taken on one night within

two hours. In Luphausia Miilleri and Nematoscelis megalops some undetermined

circumstances (p. 122, note) had concentrated these species at 50 fathoms at the time

when haul 310 was made, but in that haul Stylochetron Suhmii was not remarkably

plentiful; in 84 0, c, d, when the latter was abundant, no such marked increase in the

number of the other two species was noticeable. Whatever the determining stimuli

may have been, it is fairly obvious that they were not the same in the two cases; I have

no explanation of the facts to offer; no entry in the log suggests a clue in the second

case ; but I record the observation here to show how difficult it is to get any knowledge

of the factors of distribution, and (incidentally) how dangerous it is to generalise from

isolated hauls, or from one species to another. Precisely on the same footing, the higher

values for larvee by day than by night are mainly due to two hauls (30 d and 30/7),

* Omitting 246, where the comparative number of larve and adults had been lost.

+ The latter included also a considerable number of adults.

SECOND SERIES.— ZOOLOGY, VOL. x. 21

128 DR. G. H. FOWLER—BISCAYAN PLANKTON:

taken within two hours and a quarter; in this case it is just worth notice that they

were morning hauls after a night of very heavy rain and thunder.

In this connection it would be worth the while of future observers to consider whether

the mere presence of a ship hove-to does not, after a time, concentrate certain species:

the offal of a ship is very considerable, and means a sudden enhancement of the food-

supply, which might perhaps account for some of the apparent variations in population.

The hauls 31 0, 34a, 6, c were all made after a considerable period of laying-to.

It may be argued that the proportional catches of larvee and adults confirm the idea

that adult Schizopods can see and avoid (or swim out of) the net in daylight, and hence

are caught more plentifully by night, while the larve, moving more slowly, would

naturally be caught more abundantly in the day than adults. But if this were the sole

explanation, larve ought to have been captured equally plentifully by day and by night,

whereas they were absolutely (not relatively) taken in far greater numbers in daylight.

Besides, as Messrs. Holt and Tattersall point out, S. Swhmii must be a feeble

swimmer, if only in consequence of the length of some appendages.

The idea that even large Schizopods can (except possibly at the surface) see a net and

avoid it is not easy to grasp. Those of us who have tried to pick up white plates, or

chalk eggs, in even a few feet of water, know how rapidly the light diminishes in those

few feet. At 100 fathoms the experiments of Fol and Sarasin do not seem to

demonstrate the presence of more than a twilight of actinic rays; the red and yellow

rays are stopped in a comparatively short passage through sea-water. It may be urged,

and is quite possible, that the eyes of Schizopoda can appreciate rays invisible to our

eyes: Moseley suggested many years ago that the large eyes of some abyssal forms

might “see” the heat-rays given off by other organisms. But if ordinary light and

vision can help a Schizopod to escape capture, surely a brilliantly phosphorescent net by

night must be a more conspicuous object * than the same net used by day at any depth

beyond 25 fathoms ; and, further, in such cases as the three plentiful Schizopods tabled — |

above which extend to 100 fathoms, the captures at that depth during daylight should

approximate to those at the same depth during night, the light there being so small, and

the phosphorescence presumably as brilliant as at the surface; at least, more should

be captured at 75 than at 50 fathoms, more at 100 than 75 fathoms, yet this is not

the case (compare tables, p. 127, adults).

It seems to me to be more probable that strong swimmers, such as Amphipoda and —

Schizopoda, are actually caught in the ordinary slowly-moving tow-net, but in daylight —

make for the brighter end of it—the mouth—exactly as a bee in a room makes for the

window. It is in the experience of every tow-netter that a’ wide-meshed net +, which

allows of a faster current through it, catches more of such organisms than a fine-meshed

net, in which the current is reduced. But I doubt if this accounts for all the facts; it

* Mr. Holt tells me that the reason that bright moonlight is good for mackerel-fishing is alleged to be that the

phosphorescent nets are less conspicuous in the bright light.

+ We failed to tow-net advanced lobster larvee at Plymouth till a wide-meshed net was used at a comparatively

tapid pace.

THE SCHIZOPODA. 129

may account for the failure to take MWeganyctiphanes norvegica by day, but it does not,

to my thinking, explain away the apparent nocturnal rise of Huphausia Wiilleri.

SUMMARY.

The following conclusions, relative to the more plentiful species, refer, of course, only

to the area studied and to the time of the cruise. They are not necessarily, many of

them not even probably, true for distant localities under different conditions.

None of the species captured throw any light on the population of the Mesoplankton ;

all those taken in any quantity were essentially epiplanktonic. But KHuphausia

Millert ranged as deep as 250-150 fathoms, Vematoscelis megalops doubtfully to 400-

300 fathoms. Hucopia ungwiculata, a purely mesoplanktonie form, occurred as high as

900-100, and as low as 750-500 fathoms.

Euphausia Miilleri was essentially epiplanktonic, with a centre of distribution at

about 50 to 75 fathoms. It appeared to descend in small numbers as far as 250-150

fathoms. At the surface and 25 fathoms it was captured only by night, and in large

numbers by moonlight: it may be regarded as an instance of a nocturnally rising

species.

Meganyctiphanes norregica, caught comparatively in small numbers and on few

occasions, was purely epiplanktonic, and was captured only by night.

Nematoscelis megalops was essentially epiplanktonic, with a centre of distribution at

about 50-75 fathoms; afew specimens were caught at greater depths than 100 fathoms.

_ The indications of a nocturnal rise were less well marked than in Euphausia Willeri.

Stylocheiron Suhmii was the species most numerously and most frequently

represented in the collections. The centre of distribution lay again at about 50 to

75 fathoms; and it is doubtful whether the species penetrated much below 100 fathoms.

The expectation of larvee diminished, and that of adults increased, with depth down to

100 fathoms: larvee were captured in greater numbers by day, adults by night. The

indications of a nocturnal rise were not strongly marked.

Stylocheiron abbreviatum, taken rarely and in small quantities, was confined to nets

towed at 75 and 100 fathoms.

geen a

BESCAYAN PLANKTON:

Part VI.—THE COLLOID RADIOLARIA.

By R. Norris WoLFrenvDeEn, U.D., F_L.S., P.ZS.

Read Ist June, 1905.

Tue collection handed to me for examination by Dr. G. H. Fowler was contained in

80 bottles. Of these, in a few instances, the material was in a condition difficult of

identification. While such species as Thalassicolla and Chenicosphera (in which the

shell presents sufficiently distinctive characters) are comparatively easy of determination,

it must be borne in mind that the determination of species of Collozowm except in the

very recent or actually living condition is always a matter of considerable difficulty,

often of impossibility, and the diagnosis of such species is here presented with the

necessary reserve.

The material to hand contained few species, but an overwhelming preponderance of

one of them, viz. Chenicosphera, which appeared in no less than 67 gatherings.

CoLLOZOUM INERME, Haeckel.

Very few intact ‘‘ sausage-shaped” colonies were found. In most cases the colonies

were oval or more or less round and in young condition. One long colony was 15 mm.

in length, 1 mm. broad. All trace of segmentation was lost. The closely-packed

individuals contained each one central oil-globule, and were of °045 diameter sur-

rounded by numerous green cells round the zooids. This was the only intact long

colony, evidently in the young condition.

In all cases the diagnosis must be regarded as doubtful in the absence of the

occurrence of regular segmented and vacuolated colonies and the determination of the

behaviour under osmic acid, chromic acid, Ke.

CoLtLozoum Branpti, Wolfenden.

A few instances occurred of. rounded colonies about 4 mm. diameter, containing zooids

of 1 mm. diameter, each with one central oil-globule and 25-30 xanthelle. The colonies

showed no trace of vacuolation. One such colony of about 3-0 mm. diameter contained

700 zooids. In one instance a few diatoms, long and spindle-shaped, were found lying

between the zooids, of characters identical with those which I have described as occurring

in the Collozowm of the Froe Channel, to which I gave the name C. Brandti*. The

‘diagnosis of this species is again given under reserve, but it is undoubtedly not

C. inerme.

_ SpH#ROzOUM PUNCTATUM ?, Miiller.

In only one sample occurred a small colony of this species (not in very good

condition). |

* Journal Marine Biological Association, yol. vi. p. 344 (1902).

SECOND SERIES.—ZOOLOGY, VOL. X. 23

132 DR. R. N. WOLFENDEN—BISCAYAN PLANKTON :

The shanks of the needles, three at each end of the rod, were twice as long as the rod.

The length of the central rod was ‘025 mm.; that of the shanks was ‘05 mm.

“ Punctatum”-needles vary in size and proportions, and though the shanks in this

species are commonly shorter than the rod, the Biscayan specimen is probably of this

species, though not in good enough condition to determine with absolute accuracy.

THALASSICOLLA NUCLEATA, Huxley.

From the surface to 100 fathoms this species occurred in 18 cases in Dr. Fowler’s

samples. The species is too well known to require description.

Cu@nicospH@RA MuRRAYANA (Haeckel, ‘Challenger’ Report: Radiolaria).

This is the most commonly occurring Radiolarian in this collection, being present in

67 of the samples. The zooids being often of a rather larger average size than the

examples of the same species found in the Froe Channel, suggested at first a specific

difference. I have made a detailed comparison of the Biscayan examples with those

from the Feroe Channel, and there seems to be little essential difference between

the two.

Biscayan species. Feroe species.

Size of colony....| 2°6-3 mm. 2-3 mm. or a little over.

Shapevew ster « Round. Round.

Shells jy sca eres ‘17-24 mm. diameter. |; *18—16 mm. diameter.

Of unequal size. Of unequal size.

Pores | sA0isetaees About 30 in the half meridian. About 30.

| | 012--033 mm. diameter, -02—-04 mm. diameter.

Gettnk | { Of six spines. Six spines usually.

oo le a No spines between the pores. No spines between the pores.

The Biscayan specimens having been preserved for some timeshowed none of the vacuoles,

which are plainly to be recognized in the fresh northern species; and though the shells

in some colonies are distinctly larger than the Feeroe species seems ever to attain, this is

the only difference. The oval or round pores of the shell are very irregular as to size,

between three or four large pairs is often interposed a small rounded one; the bars

between the pores are not usually broader than half the diameter of the pore, but

between a few the bars are occasionally of much greater breadth. The xanthellee are

numerous, and round each zooid is a thick pseudopodia-layer with thick pseudopodia-

strands passing between two or three neighbouring individuals. Chenicosphera is of

very frequent occurrence in the Feroe Channel and round the coasts of Shetland, in

THE COLLOID RADIOLARIA. 133

which region it is, in my experience, by far the most commonly occurring of the colony-

forming Radiolaria, and it appears to be equally common in the Bay of Biscay. The

species described by Prof. Cleve as Trypanosphera brachysiphon * from the Atlantic bore

such a strong resemblance to Chenicosphera Murrayana that in 1902 + I suggested the

identity. I have latterly forwarded some specimens of the Biscayan species to Prof. Cleve

for comparison with his described species, and he has replied to me that they are the

same, and that his Zrypanosphera is really Chenicosphera Murrayana. The absence of

a tube-process round the pores of course removes the species from the former genus of

Haeckel. The elevated ridge bearing the short teeth round the pore is small, it and the

spines or teeth not being in height equal to more than half the diameter of the pore.

In the Feeroe Channel examples I have been fortunate enough to observe the species

in the Isospore stage, but I do not find this stage in Dr. Fowler’s specimens.

NOTE TO THE FOREGOING.

By G, HerBert Fow Ler.

These Colloid Radiolarians are generally regarded as being distinctively surface forms,

but an analysis of the captures by no means bears out this idea.

Collozoum Thalassicolla | Cheenicosphera| All species

inerme. nucleata, Murrayanum. together.

| At 0 fathoms ........ 36 5 36 52

ip. 2a Ree aes cee 25 16 66 75

pc CU aa eee 46 30 84. 84

COI sy Ma eeih. 355 18 18 72 72

PUA Mastae ists sr shee ste 40 40 90 95

The table gives, for each depth, the percentage of the hauls at that depth in which

the three commonest species were captured, or (in the fourth column) in which one or

other of the three species was captured. It shows that while Collozowm inerme was fairly

evenly distributed, the expectation of capture of the other two species increased with

* K. Sv. Vet.-Akad. Handlingar, Band 34.

T Journal Marine Biol. Assoc. 1902, p. 353: ‘ The Plankton of the Feroe Channel, &c.”

134 DR, G. H. FOWLER—BISCAYAN PLANKTON :

the depth *. In this as in similar tables in the earlier reports the excess of the captures

at 50 fathoms over those at 25 and 75 fathoms is puzzling.

On the other hand, although not essentially surface forms, they were distinctly

epiplanktonic, not descending to great depths. The specimens from 21a, and from

36 f-l, may have been captured at any point between their extreme depth and the

surface, but specimens from the closing-nets, marked F in the table (p. 135), were in all

cases few and fragmentary, and were probably dead specimens sinking to the bottom.

These Radiolaria probably did not live much below 100 fathoms.

When the occurrences were plotted on “time-depth ” tables, or “day, night, and rain”

tables, no evidence was forthcoming of any movement of these Radiolaria in response to

light, darkness, or rain. For example, Chanicosphera Murrayana occurred at the

surface in 45 per cent. of the “day” hauls, 42 per cent. of the “night” hauls; as it

also occurred at the surface in two out of the three “rain” hauls, we may conclude that

it does not sink in consequence of wet weather. We know from Prof. Brandt's experi-

ments that Thalassicolla can rise and sink with considerable rapidity in response

to stimuli, but unfortunately it was not captured sufficiently frequently to give any

indications.

* The nine hauls wiih a net of 180 meshes per linear inch, referred to in previous reports, have again been

omitted. That they failed to catch even these Radiolaria, which have no power of swimming, is a fairly conclusive

proof of the uselessness of such fine-meshed nets for a general fauna, although doubtless necessary for Coccospheres,

Diatoms, and minute Protozoa.

THE COLLOID RADIOLARIA. 135

| | | = pi | 2

| s/s, Ss | es |3s aA

i Site as zs ss Ad Depth i 2. 2's 2S Se | fsos

fethome, | He. | 82) 28) 88/25 | FE | fathom, | Ho | $2 | 88) 88) ES | FF

, Sees Peels s Re | 85/88/82] 838 | 88 |

SS} 8/28) S& | 88 | SS (Se | OS 8 |) SS!

S | S ay | = i) | Ss § ar gS Ss

= ee | —— — ee ee =) |

| |

| 100—0 Qh oy er SW Ae:

| 211 + at ae ak

| 22a |. ar + 4

| QL ON ba iy, +

24d A ere at

| j | | |

0 2le 24e ae me ss Si

21f 25d | + Be ae |

21% | + 309 a «fe eae ay

22 d SF + |) + 30h as ak + + |

| Qe | 32d st ai) Se aeite * |

2g | + | B27 + ae | +

236 ae) Bi aan . The cats |

2: aie ice |

se + | at 33d | | ae |

Be 345

24 Seah? + +

2 | 35 Si 5

S| ay | t 8 | a

| 24h | 357 42 aD Neck

247 + 35.2 s “= |i

| 24k | 360 ce 4

| 25a | 36 e ey at

255 | 150-0 | 36f a

25h , 150-50 | 2lp

257 op 150—100 21x

251 | 200-0 [peat +

30¢ 369 +

32¢ 200—100 21b

| 884 ate ty F

336 avs 5 + 26e

25—0 26a i? ie 34h F

4 306 ate =a 35m

380m 85n

Bla 35t

326 ae ae 250—0 36h

| 82e a oat 367 ae

33e ve =i 850

| 83¢ xe ae = 250—1450 | ae

j 5s

rn ea | * | + | soot ®t ivan +

85u joe 300—200 | 21e

36c | + th | 26f | I

50—0 PAG) | i= +- + oy 351

25e | + | 850—0 361 +

25g 400—300 | 21k

25k as 1 en 321

26e a 2 roa ; 35k

Roe? |) te de ‘ a 500—400 21m

sod | + sof + |] + | 854

Sli at | 357

Soe © hl Ske + | + | 750-500 | 996

B2h + ie + | 804 :

33.¢ + | | / + + | Ste es kK

33h | x + | S847 F

36d | 4 | 1000-750 | 98a

75—0 30f =) | 27e

329 4 + 31d

32m | 82F

320 } | s2k |

83h | 1250—1000 24a _ |

34e are a | | arb | |

35 oO + c ]

ee ail 5: + | 1500—1250' 25f | |

85 e on ir || 80% |

35y a a + 2000-1500 2%5e

36a ae | irae Wear? | |

a ay) 28

SECOND SERIES.—ZOOLOGY, VOL. X.

Fow er.

TRANS. LINN. SOC. SER. 2, ZOOL. VOL. X. FI, 8.

Fic. 1.

. TropHozoor A (? = Doziorvm Trironrs, HuRDMAN), FROM THE LUFT SIDE. THE STALK WAS LONG

. Tropnozooi A: ANOTHER SPECIMEN, FROM THE RIGHT SIDE, THE GILE-SLITS OMITTED. TUE STALK

. Tropuozoorp B, FROM THE LEFT SIDE.

. INTESTINE OF THE SAME SPECIMEN, FROM THE RIGHT SIDE.

BISCAYAN THALIACEA.

ALL FIGURES ARE MULTIPLIED 37 TIMES.

Brastozoorp A (? = Doriorum Trironrs, HERDMAN).

AND TURNED DOWNWARDS 'T0 A NEARLY TRIANGULAR BASE.

WAS SHORT AND CARRIED TWO LARGE FLAPS, APPARTNTLY OF THST-SUBSTANCE, FOLDED OVER.

end. endostyle. ng. nerve-ganglion.

int. intestine. oes. oesophagus.

Fow zr. TRANS. LINN. SOC. SER. 2, ZOOL. VOL. X. Pl. 9.

DISTRIBUTION OF THALIACEA.

ON THIS PLATH HAVE BEEN APPROXIMATELY CHARTED THE RECORDS OF VARIOUS SPECIES OF DoLioLUM IN

THN NEIGHBOURHOOD OF THE Brirish IsLaNps ; THBY INCLUDE THE CAPTURES Or H.M.S. ‘ Trrron’

(1882), H.M.S. ‘ Rusnarcn’ (1896, 1897, 1900), s.s. ‘ Honsarra’ (1885), s.s. ‘ NavionaL’ (GprMan

Pranxron Expnprrion, 1889),

AS ALL ARE EPIPLANKION RECORDS, EXCEPT THOSE OF DENTICULATUM AND D. sp., BORGERT, VME MEAN

ANNUAL SURFACE ISOTHERMS HAYE ALSO BEEN PLOTPED IN DEGREES CENTIGRADE FROM Dr. Scnorr’s

RESULTS.

D. D. penticvuLatem, sp. D. sp., BorGerr,

K. D. Krownr. T. D. TriTonts,

N. D. Narionacis.

[ 137 ]

BIsCAYAN Plan kT ON

Part VII—MOLLUSCA (excluding CrpHanopopA).

By Dr. Paut PELSENEER, Professeur a l Ecole Normale de Gand.

(Plates 10-12.)

With a Note on their Distribution.

By G. HERBERT Fow ter, B.A., Ph.D., PLS, PZS.

. Read Ist June, 1905.

;

TABLE DES MATIERES.

, Page

Mirena OC DLOLiperevate tan ctesecsteles aps ssysr sive) oe 15/5): nie. 614 ofa aroneyay 0.4 ie ape lan Shape opay eters afelsh ol ere) <1, nie. a2 137

A. Siiichnta@G@.Gir Moning Wty on kod gopbneeees pabd coool ccs no osoSocudsooKeN Teor 138

Il, Lomas Cees set etn Sasa ees we ReeeER eon. co.on olan 0s Bim morn moni 138

ie ltarvesra unermeulercoguille, dextrer.. «a .2 1 ths eteenetistenaeteretans relate ejetole eta! wis 139

Ul. Cena niln (Gy iitkets Bpppee Bee took pon cc rim oop uomonuadonaD 139

Pa OR CLLTOPIELLEN (2p) se SPo1 DB 5 5) = au cre le onaiehalapeiey “NoRete TRA tN eVereiey ale eto=tavel-¥e sks) « 139

Sree COLUAUe LOMO LULEUR, ) CLULOVS.0fe).< 151-1 > toda een eer et aaben rela elcl este 9/=\aiae.= = 140

Ah. MGMT. ROh cigicidl COIS IEG CEE CDOT OC IDn Dn 0 OUCr6 og Seen nn hone Cat 141

ii. Larves & une seule coquille, sénestre ou hétérostrophe ..........-..-.+.055 141

EVOL ELUM Deu steta ies =3s: «sy e-a'a16. ora arenalo enstelthe ote aeaeeeeaemer et efers isis 4.27 -Ncar ai) 141

Line NE VeSRAV A CUKs COMUMLESLE <<) 04 < 5 <\ciche tole aateyenctottehe aRara evecwrerats sis/slarers o. <i 142

Sh LETTING Ch Th oR GGORDOREC noo domo OC oe, occonGo > EEdno Gr ema nOC 142

Te Tia alliaiG kn: CoO mer Bema ee obec moc 06? Sc cdo pes SUoIgEe DEDBOD 142

Be. EA RUE CTA) Bal 10S SOOM B ORION DUOC On 6 ID 0 HO UCD ROC COI CrERon 143

Remarques sur les trois formes précédentes ........-- 0000 e eee eee 143

SA emmENe GeO DOCG Mmertmcaiys ere chclere.c cose 6.0 + = tie tha detepure ciaPeceoneisielaiageleys/¢ cic is eres societies «5 143

Oh (COR TETZAC) Stig BERRIES: Obie \nG 60 UOO2. 07. ChOO.0o DEH UeeeOenC 143

LIT, QUI EOIGE? bo oglé cote PROBE Onr Donen COpc | Cot 05 CoComo RAS DObmaera no 146

Os Peraske triacantha (Fischer) <j. «= «iets mieiets cis) the emis asie 20 as o's acl 146

Me eraclim OFeutepind, SP. We. os o oe ea sisleeeeidve Maly sales. s S58 oe eens cnee 146

Organisation et Relations phylogénétiques du Genre Peraclis ........ 147

La Lumacina retroversa, Fleming «2... 2.2 cscs ccee ce sete eee eset cosine 149

Use Glompyramidata, Brown’ 1... .2 coe. sweet cee s sone teeee cere t ence 149

Wem QU GNCUSDIdGtas BOSC. << are een on wiv cieleieena ease seco ee sects ear es 149

: 15. Cavolinia inflema, Lesueur ........ esc ee ee ee eee etter eee eee eeee 149

LN. CDG 00 C 5.4 SERIE OIE SERRE Cap Cc Oi Oe 149

16.) Fowlerina Zetesios, gon. Cb sp. UN. 2... cceceee eee teeters tenees 149

Remarques sur les diverses espéces de Clionid@ ......-. 6.0000 e eens 150

Vo TL GL iene sae © ads aN ene OP eel i WE ee ea ice br 151

s«4

138 DR. P. PELSENEER—BISCAYAN PLANKTON :

PENDANT le mois de juillet de 1900, sur H.ML.S. ‘ Research,’ Dr. G. Herbert Fowler a

recueilli le matériel suivant de Mollusques planktoniques, par une distance de 800 kilo-

métres, environ, des cdtes les plus voisines (entre 46° 43’ et 47° 29’ N., d'une part, et

7° 15' et 8° 18’ W., d’autre part).

Les péches ont été exécutées de jour et de nuit, entre la surface et 2000 brasses de

profondeur ; mais elles n’ont pas rapporté de Mollusques au deld de 1500-1250 brasses.

La collection recueillie comprenait prés de 350 spécimens appartenant 4 une vingtaine

Wespeces dont quelques unes seulement étaient représentées par de nombreux individus

(et peuvent par conséquent étre considérées comme trés abondantes dans les couches

explorées de la région en question).

Les occurrences des espéces sont enregistrés au table, pp. 156, 157, 4 la fin du Mémoire.

A. SYSTEMATIQUE ET MORPHOLOGIE.

I. LARVES DE GASTROPODES.

Tl est souvent difficile de déterminer & quel genre (et a fortiori 4 quelle espéce)

appartiennent les larves planktoniques de Gastropodes; car, bien des fois elles peuvent

différer beaucoup de l’adulte, par leurs caractéres extérieurs.

Aussi, un grand nombre de genres particuliers ont-ils été fondés autrefois pour ces

petites formes pélagiques, dont plusieurs étaient alors considérées comme appartenaut

aux anciens groupes des ‘‘ Ptéropodes” ou des “ Hétéropodes”: Cirropteron, Sars,

Stnusigera et Brownia, @Orbigny, Cheletropis et MacGillivraya, Forbes, Echinospira,

Krohn, Calcarella, Souleyet, Jasonilla, MacDonald, Hthella, Adams, etc. .

MacDonald le premier reconnut avec certitude que plusieurs de ces formes se —

rapportaient & des genres déja connus & état adulte*. Et aujourd’hui il est admis

quaucun de ces genres n’est valable, bien que les affinités de tous ne soient pas encore

connues (il n’y a que dans certains catalogues conchyliologiques qu’on les trouve encore

conservés).

Récemment Simroth a décrit un grand nombre de larves pélagiques de Gastropodes,

provenant de Expédition du ‘ National’; mais il n’a pu en identifier quune minime

partie f.

Cette identification offre toujours des difficultés considérables. C’est le cas aussi pour

les larves recueillies par la ‘ Research,’ dont les fluides conservateurs avaient altéré les

coquilles calcaires en beaucoup de cas f.

Restaient, comme moyen de détermination, la forme générale, le velum et surtout

Vopercule et la radula. Toutefois, dans ces petites larves, la radula est d'une petitesse

* MacDonald: ‘On the probable Metamorphosis of Pedicularia and other Forms ; affording Presumptive Evidence

that the Pelagic Gasteropoda, so-called, are not adult Forms, but, as it were, the Larve of well-known Genera, and

perhaps confined to Species living in Deep Water,” Trans. Linn. Soc. London, vol. xxii. p. 241 (1859).

7 Simroth: ‘ Die Gastropoden der Plankton-Expedition,’ 1895.

¢ [This was due to the unfortunate employment of corrosive sublimate or picric acid in many cases. Formalin

alone, which spares even the finest spines of pelagic Foraminifera, did not appear to attack molluscan shells—

(5 Jel Ja]

MOLLUSCA. 139

extréme et se perd facilement dans les manipulations faites pour l’isoler; en outre, elle

nexiste pas chez tous les Gastropodes (par exemple dans les Eulimidze et Pyramidellide).

D’autre part, l’opercule larvaire est aussi fort petit, fragile, trés mince, transparent et a

détails de structure souvent peu perceptibles.

Aussi n’ai-je pu identifier avec une certitude suffisante que quelques unes de ces

larves.

i. Larves a une seule coquille, dextre.

1. CoRALLIoPHItA (?), sp. A. (PI. 10. figs. 1, 2.)

= Trichotropis fimbriata, Jeffreys: ‘On the Mollusca procured during the ‘ Lightning’ and

‘Porcupine’ Expeditions, 1868-70 [part ix.],”’ Proc. Zool. Soc. London, 1885, p. 48, pl. 5.

lie Ce

Coquille cornée, & poils longs, disposés sur quelques rangées seulement; spire assez

allongée.—Velum formé de quatre longs lobes, sans pigment. Deux tentacules et deux

yeux. Radula absente. Opercule anucleus assez latéral, mais vers la columelle, spiralé,

i spirale sénestre, peu marquée, comme dans l'espéce suivante (fig. 4).

Distribution. La coquille vide de cette larve a été prise aux environs des Féroé, par le

‘Porcupine,’ jusqu’a 816 fathoms, avec l’espéece suivante, mais moins abondante.

2. CORALLIOPHILA (?), sp. B. (Pl. 10. figs. 3, 4.)

= Trichotropis densistriata, Jeffreys: “On the Mollusca procured during the ‘ Lightning’ and

‘ Porcupine’ Expeditions, 1868-70 [ part ix.],”’ Proc. Zool. Soe. London, 1885, p. 48, pl. 5. fig. 8.

Coquille cornée, a spire plus courte que l’espéce précédente, ornée de nombreuses

rangées spirales de poils peu allongés. Velum divisé en 4 longs lobes sans pigment.

Deux tentacules, chacun avec un ceil d la base externe; otocystes avec un otolithe.

Pied légérement échancré en arriére. Radula absente. Opercule trés semblable a celui

de Vespéce précédente (fig. 4).

Distribution. Trouvé, avec la précédente, a l'état de coquille vide, 4816 fathoms, par le

‘Porcupine,’ prés des Féroé; également par le ‘Talisman,’ aupres du Cap Vert, par

1192 fathoms.

Cette espéce ressemble aussi a la larve représentée par Simroth (doc. cit. pl. 11. fig. 2),

sous le nom de NVassa ?, et qui provient de |’ Atlantique oriental.

Remarque au sujet de A et B.—Aucune de ces deux larves ne posséde de radula; la

forme susdite de Simroth est dans le méme cas. Ce n’est done pas un Zrichotropis, ni

_ Waillewrs une forme adulte (ce que supposait Jeffreys).

: J’opine pour des Coralliophila (=Pseudomurex, Monterosato, d’aprés beaucoup de

conchyliologistes) ; c'est un des rares genres de Gastropodes Pectinibranchia dépourvus

de radula; il a en méme temps un opercule 4 nucleus latéral, et des otocystes a otolithe.

En outre, certaines espéces de ce genre vivent dans le Golfe de Gascogne: C. alucoides,

Blainville (=lamellosa, Jan), et C. edonus, Watson (tous deux recueillis par le ‘ Caudan,’

& 180 et 400 m.*); et O. (Pseudomurex) basileus, Dautzenberg et Fischer, au N. de la

Corogne, entre 748 et 1268 m.

* Koehler: “ Résultats scientifiques de la Campagne du ‘ Caudan,’” Ann. Uniy. Lyon, 1896, pp. 154, 158.

24*

140 DR. P. PELSENEER—BISCAYAN PLANKTON :

La larve susindiquée de Simroth a été obtenue dans presque tout l’ Atlantique oriental,

et la forme B, par le ‘ Talisman,’ pres du Cap Vert; or il existe aussi des Coralliophila

au voisinage des iles Atlantiques tropicales; C. lactuca, Dall, aux Acores; C. (Pseudo-

murex) basileus, Dautzenberg et Fischer, également aux Acores.

3. COLUMBELLA HALIAETI, Jeffreys. (Pl. 10. figs. 5-9.)

(=C. costulata, Cantraine.)

x .

Coquille ventrue, siphonée, a4 spire modérément allongée, lisse (& peine marquée vers

Vendroit le plus saillant des tours, d’une double strie spirale) (fig. 5).

Velum quadrilobé (figs. 6, 7), dont les lobes sont fort larges. Deux yeux. Radula

rachiglosse, a dent centrale encore peu développée (ne résistant pas & Vaction de la

potasse caustique) ; dents latérales tout-a-fait caractéristiques et propres aux Columbella

(ou Pyrene)* (fig. 9).

Opercule spiralé, paucispiré, 4 nucleus tout-a-fait latéral (fig. 8), ressemblant quelque

peu & celui figuré par Simroth, sous le nom de “ Zriton?” 7, mais vu par sa face

intérieure certainement.

Dans la région 8.W. de l'Europe, il y a une espece Jlitiorale de Columbella: C. rustica,

Linné, du Portugal t. Mais la radula différe notablement de celle de notre larve; et

Wailleurs, les larves d’espéces littorales ne se rencontrent pas 4 une telle distance

(300 kilometres) des cotes.

Au contraire C. (Pyrene) haliaéti est abondant dans la profondeur de l’Atlantique

Nord: Shetlands, Norvege, Finmark, Groénland, et méme Amérique du N. (Massa-

chusetts: Gulf of Maine, Bay of Chesapeake §); et cette espece est enfin fréquente dans

le Golfe de Gascogne: 1107 et 1576 m. (Expédition du ‘ Travailleur ’).

Tl est done trés vraisemblable que c’est & cette forme que se rapporte notre larve,

malgré une minime différence dans la radula, telle qwelle est figurée pour Padulte par

Sars |.

L’absolue certitude au sujet du genre, permet de faire connaitre la transformation

subie par Vopercule. Celui-ci—écailleux, triangulaire et @ nucleus latéral, chez ’aduite—

est nettement spiralé chez la larve (fig. 8). Un fait analogue s’observe dans Nassa

(fig. 18) et ? Coralliophila (fig. 4); ce qui rend probable que tous les opercules sont

spiralés 4 Vorigine. La partie la plus antérieure, dépassant la spire, est une formation

plus récente, résultant de la modification de forme de louverture coquilliere; une

semblable addition s’observe encore dans dautres formes, ott la spire operculaire reste

visible chez ladulte (Stgaretus) 4.

* Vide Troschel: ‘Das Gebiss der Schnecken,’ vol. ii. pl. 9.—Fischer: ‘ Manuel de Conchyliologie,’ p. 637,—

Cooke: ‘* Molluses,’ p. 123.

+ Simroth: ‘ Die Gastropoden der Plankton-Expedition,’ 1895, pl. 5. fig. 3.

+ Kobelt : ‘Prodromus Faun Molluscorum Testacecrum maria Europa inhabitantium,’ 1886, p. 56.

§ Verrill: Trans, Connecticut Acad. vol. v. pl. 43. fig. 7.

|| Sars: ‘Mollusca Begionis Arctice Norvegie,’ 1878, pl. 10. fig. 2.

Y| Souleyet : ‘Zoologic du Voyage de la ‘ Bonite,’ Mollusques, pl. 35. figs. 20, 21.

MOLLUSCA. 141

4, Natitca sp. (Pl. 10. figs. 12-15.)

Coquille globuleuse, lisse et sans coloration, & spire trés peu saillante (fig. 12).

Velum tetralobé, portant une tache pigmentaire 4 l’extrémité libre de chaque lobe

(fig. 14), comme une larve de Nassa des Féroé et certains “ Sinusigera.” Radula teenio-

glosse (2.1.1.1.2), naticoide (fig. 13), avec une premiére dent marginale pourvue de

deux denticules caractéristiques du “sous-genre” Zunatia. Mandibules formées

d’écailles imbriquées, & pointes saillantes.

Opercule corné, semi-lunaire, paucispiré (fig. 15).

Le spécimen de la station 21 différait des autres seulement par son velum sans taches

pigmentées; pour le reste, il avait la méme radula, les mémes mandibules et le méme

opercule. Toutefois, cette différence ne me parait pas dée a la dissolution du pigment

dans le liquide conservateur ; car, la larve 21 / était dans le formol, de méme que 310

et 33g, et 246 dans alcool; et les trois derniers avaient taches pigmentaires également

bien conservées. Peut-étre sont ce des larves de deux espéces trés voisines.

En tout cas, ces quatre larves appartiennent & des Natica ’ opercule corné (et non

calcaire) du groupe Naticina ou Lunatia, avec une premiére dent marginale portant

deux denticules terminaux subégaux (le plus postérieur étant le plus petit). Troschel

avait déja reconnu Jl'existence d’un groupe naturel ainsi caractérisé, comprenant

notamment: JV. helicoides, N. lactea, NV. grenlandica et N. pallida (ces deux derniéres

peut-etre identiques *.

Ce groupe renferme diverses formes abyssales, V. granlandica, N. nana, ete. La

campagne du ‘Caudan’ a signalé WV. nana, Lovén, dans le Golfe de Gascogne; mais la

radula en est un peu différente t+. Le méme campagne a rapporté aussi, de 1710 m., des

““especes nouvelles” voisines de nana et de grenlandica. Enfin, Expédition du

‘Travailleur’ a trouvé assez abondamment dans le Golfe de Gascogne, \. subplicata,

Jeffreys: cest peut-étre a cette espece qu il faudrait rapporter notre larve; mais la

radula de NV. subplicata n’est pas connue.

ii. Larves & une seule coquille, sénestre ou hétérostrophe.

5. SomariumM? sp. (Pl. 10. figs. 10, 11.)

Coquille pseudosénestre, sans spire saillante, ressemblant aux formes dites ‘* Ayadina,”

et n’appartenant pas & un Thécosome Limacinidee, car la larve qui s’y trouve posséde un

velum tétralobé et deux gros yeux. L’animal est dextre, avec le coeur & gauche: e’est

done bien une larve de Gastropode 4 coquille dont le sommet est hétérostrophe (ou

“anastrophe” daprés Dautzenberg et Fischer, qui réservent le terme hétérostrophie au

changement de direction de l’axe et non au changement de sens de l’enroulement).

Une autre preuve sen trouve encore dans Vopercule (fig. 11); celui-ci est spiralé, A

enroulement sénestre et & spire dont le nucléus est dirigé vers le sommet de la coquille

larvaire (fig. 10); or, on sait que ce nucléus est toujours dirigé vers l’ombilic de

* Troschel: *‘ Das Gebiss der Schnecken,’ vol. i. p. 74.

t+ Sars: ‘ Mollusca Regionis Arctica Norvegie,’ pl. 5, fig. i4.

142 DR. P. PELSENEER—BISCAYAN PLANKTON :

Vadulte. Cet opercule est orbiculaire, concave extérieurement et & petit nucléus saillant

intérieurement.

Je rapporte cette larve au genre Solarium. On sait que chez celui-ci, le sommet est

hétérostrophe *. Une figure de Hedley en donne une démonstration bien nette 7. La

radula m’a échappé ; ce que j’attribue 4 la grande longueur de la trompe, qui peut étre

plus ou moins invaginée et entrainer la radula jusqu’aupres de l’estomac }; de sorte

qu’on ne la trouve pas a la place habituelle.

Il existe d’ailleurs dans le Golfe de Gascogne plusieurs Solarium: notamment

S. archite, Costa, et S. fallaciosum, Tiberi (=S. siculwm, Cantraine), a 180 et

400 m. (Campagne du ‘Caudan’); et S. pseudoperspectivum, Brocchi (Expédition du

‘Travailleur ’).

ill. Larves a deux coquilles.

6. LAMELLARIA, sp. A. (PI. 10. figs. 20, 21; Pl. 11. figs. 25, 26, 27.)

Coquille externe “ cartilagineuse,’ aplatie latéralement, 4 tours tous visibles, pourvue

de deux carénes centrales et de deux carénes latévales peu saillantes, & dents petites et

plutdt courtes. Ouverture caractérisée par un rostre ventral, médian, non appliqué sur

le tour précédent (fig. 21).

Coquille interne ou définitive (figs. 26, 27), auriforme, a spire courte, formée de

24 tours, peu saillante.

Pied sans opercule (celui-ci étant peut-¢tre déja caduc, a lage de la larve recueillie).

Velum & quatre lobes saillants (fig. 26). Radula ayant pour formule 1.1.1, a dent

centrale en chevron, légérement asymétrique, la branche droite (& gauche sur la figure)

étant la plus grande ; c’est la dentition tout-i-fait caractéristique de Lamellaria et spéciale

a ce genre.

Cette forme me parait ressembler seulement a la coquille figurée par Lo Bianco §, sous

le nom de Echinospira compressa, bien que la larve, sa radula et sa coquille définitive n’en

soient pas connues.

7. LAMELLARIIDE. (FI. 10. figs. 16-19.)

Coquille externe “cartilagineuse,”’ aplatie latéralement, 4 dernier tour cachant les

précédents, & carénes presque nulles et sans lignes d’épines; présentant une légére

asymétrie, le rostre dorsal de l’ouverture étant dirigé vers le cédté “ombilical” ou

gauche.—Coquille définitive excessivement mince, formée de 25 tours, croissant trés

rapidement, & ouverture orbiculaire trés grande, et a spire tres peu saillante.

* Jousseaume: Bull. Soc. Zool. France, vii. 1882, p. xxx.—Watson: ‘“ Report on the Gastropoda,” Zool. Chall.

1886, p. 137.—Dautzenberg et Fischer: Mém. Soc. Zool. France, ix. 1896, p. 57.

+ Hedley: ‘“ Scientific Results of the Trawling Expedition of H.M.C.S. ‘Thetis,’ Mollusca, part ii.” Memoirs of

Australian Museum, iv. 1903, p. 349, fig. 73.

+ Troschel: ‘Das Gebiss der Schnecken,’ vol. ii. pl. 15. fig. 6.

§ Lo Bianco: ‘La pesche abissali eseguite da F. A. Krupp col yacht ‘ Puritan,’ nelle adiacenze di Capri ed

in altre localita del Mediterranea,” Mitteilungen zool. Stat. Neapel, xvi. 1903, p. 179, pl. 8. fig. 23.

ce ee LS se

MOLLUSCA. 143

Velum a quatre lobes saillants (fig. 19) ; tentacule droit, seul bien développé (comme

dans la larve nageuse de certaines autres Gastropodes). La radula n’a pas été trouvée

et a peut-¢tre échappé.

Opercule vitré, lisse et mince, spiralé, 4 plusieurs tours (fig. 18).

8. LAMELLARIA, sp. B. (Pl. 10, figs. 22, 23; Pl. 11. figs. 24, 28, 29.)

Coquille externe “‘cartilagineuse,” épaisse, 4 ouverture étroite dans le sens dorso-

ventral, 4 carénes écartées l’une de l'autre et portant des épines robustes et saillantes.

Dernier tour cachant complétement les précédents. Ouverture a rostre dorsal trés

saillant et & bord ventral appliqué sur la coquille-—Coquille définitive capuliforme, non

enroulée.

Velum a six lobes (fig. 24) allongés. Deux tentacules trés longs et égaux ; branchie

présentant déja trois filaments. Radula ayant pour formule 1.1.1, et constituée des

dents caractéristiques de Lamellaria (fig. 29). Mandibules paires et séparées (fig. 28),

epineuses et peu élevées, imparfaitement symétriques, ressemblant a celles observées par

Krohn sur la larve Lehinospira diaphana* ; elles ressemblent aussi vaguement A celles

de Marsenina t+, et différent de celles de Lamellaria adulte, o& comme on sait, la

mandibule est impaire (résultant de deux piéces soudées sur la ligne médiane).—Pas

dopercule.

Remarques sur les trois formes précédentes.

1°.—La deuxiéme larve ressemble 4 celle décrite par MacDonald}, ce qui me fait

supposer quelle avait une radula de la formule 2.1.1.1.2, comme celle-lA; ce caractére,

joint a la croissance rapide des tours de la coquille définitive et & son ouverture

orbiculaire, me portent & voir dans cette larve l’état jeune dun Velutina. On sait

quune espéce de ce genre: V. (Velutella) flevilis, Montagu, vit dans les zones pro-

fondes de Atlantique Nord.

2°.—Les deux autres larves appartiennent sirement & des Lamellaria; la derniére

ressemble & celle que Krohn a décrite sous le nom de Echinospira diaphana (mémes

coquille, radula et mandibules, méme nombre de lobes au velum), et que cet auteur

considere comme la larve de Lamellaria perspicua, Linne,

La seule autre espéce de Lamellaria connue a Vétat adulte dans l’Atlantique N. est

L. tenuis, Jeffreys (recueillie par le ‘ Porcupine,’ par 816 brasses) ; peut-Ctre la larve A s’y

rapporte-t-elle ?

II. HereroroDe.

9. CARINARIA sp. (Pl. 11. figs. 30-40.)

1°.—83 prises ont donné en abondance des larves véligéres de Gastropode, & coquille

spiralée, aplatie, “ valvatiforme,” représentée figs. 30, 34, 35. Ces larves, si communes, ne

manquent que aux stations nos. 22, 27 et 29, c’est-d-dire dans les grandes profondeurs ;

* Krohn, “ Nachtrag zu dem Aufsatze iiber die Echinospira diaphana,” Arch. f. Naturgesch. 1858.—Troschel :

* Das Gebiss der Schnecken,’ vol. i. pl. 16. fig. 2.

+ Bergh: ‘ Report on the Marseniidw,” Zool. ‘Challenger’ Exped. pt. xI. pl. i. fig. 14.

$~ MacDonald: “On the probable Metamorphosis of Pedicularia,” Trans. Linn. Soc. Lond. xxii, pl. 42.

85 12,13,

144 DR, P. PELSENEER—BISCAYAN PLANKTON:

on peut donc dire que ces organismes pullulent dans les eaux superficielles; ils n’ont

jamais été rencontré au-dessous de 200 brasses, ils n’ont jamais été pris dans des filets

fermés avant d’atteindre 4 la surface, et ils presque tous été capturés entre 50 et

0 brasses, 4: fois entre 100 et 0 brasses, 1 seule fois (1 exemplaire) entre 350 et 0 brasses.

L’examen a montré que ces Jarves appartiennent 4 un Hétéropode, par les caractéres

suivants :—

(1°) deux gros yeux a axes allongés, & cristallin éloigné de la rétine (fig. 44) ;

(2°) opercule vitré, spiralé, paucispiré, sénestre (figs. 34, 41) (comme dans tous les

Hétéropodes adultes quand ils sont opereulés; les opercules représentés erroné-

ment dextres *, sont vus par la face interne) ;

(8°) velum a 6 lobes (fig. 38): caractére connu seulement chez les Atlantide,

Carinariide 7, quelques Strombidie { et Lamellaria (fig. 24);

(4°) nageoire pédieuse aplatie bilatéralement, “ mésopodium,” avec un rudiment

saillant de ventouse a son bord ventral (fig. 31, ¢.0.);

(5°) et s'il restait le moindre doute, la radula, 4 formule 3.1.3, identique a celle

des Hétéropodes, caractéristique par la forme de la dent centrale et de la

premiére latérale (fig. 39).

Cette larve est peut-étre la méme que celle renseignée par Simroth § dans

la région N.E. de Atlantique, vers 25° N. et 31° W.

2°.—Quelques prises ont donné aussi un jeune Hétéropode immature, testacé, mais a

corps non rétractile dans la coquille (fig. 36), laquelle est pareille a celle de la larve

ci-dessus. Voici, da reste, comment l’on peut décrire ce jeune Hétéropode:

Téte €norme, & masse buccale trés forte; deux tentacules (dont le droit est parfois

absent: caractere sexuel ?); masse viscérale enroulée en spirale et tout entiére contenue

dans une coquille entiérement spiralée aussi. Manteau faisant antérieurement saillie

sur la ligne médiane, par un lobe ( pa.) protégeant la branchie (laquelle comprend 6 ou 7

filaments). Nageoire a ventouse postérieure. Métapodium allongé, portant a son

extrémité libre une nageoire ventrale, horizontale, bifurquée, 4 pigment brun sombre

sur sa face inférieure (fig. 833).—Dimensions: 8 millimétres au maximum.

3°.—Lidentité de cet Hétéropode immature avec la larve ci-dessus, ressort bien des

observations suivantes :—

(a) identité de la coquille (figs. 32, 34) ;

(4) identité de la radula;

(¢) identité de la nageoire métapodiale (7i.') avec celle que présentent les individus

agés de la larve (fig. 31), sur le lobe operculigére (=métapodium) mais qui est

alors asymétrique (le lobe droit étant le plus grand) ;

* Simroth: ‘ Bronn’s Thierreich,’ Bd. iii. Gastropoda, pl. 19. 26.—Vayssiére: ‘“‘ Résultats des Campagnes scien-

tifiques accomplies sur son Yacht par Albert 1", Prince souverain de Monaco,” fascicule xxvi., Mollusques Hétéro-

podes, 1904, pl. 6. fig. 87.

7 Gegenbaur: ‘ Untersuchungen tiber Pteropoden und Heteropoden,’ 1855, pl. 8. figs. 1, 2.

= MacDonald: “ Further Observations on the Anatomy of Macgillivraya, Cheletropis, and allied Genera of Pelagic

Gastropoda,” Phil. Trans. Roy. Soc. London, 1865, pl. 16. fig. 18.

§ Simroth: ‘ Die Gastropoden der Plankton-Expedition,’ p. 135, pl. 18. figs. 13, 17.

MOLLUSCA, 145

(d) identité des stations: le jeune hétéropode et la larve ont été recueillis quatre fois

ensemble, 4 la méme profondeur (toujours pendant la nuit).

Les chiffres de la table (pp. 156, 157) comprennent les spécimens de ce jeune immature,

provenants des prises :—

307. 50 to 0 fathoms. 1 specimen.

316. 50 to 0 fathoms. 3 specimens.

32 a. 50 to O fathoms. 1 specimen.

34a. 25 to O fathoms. 1 specimen.

La comparaison de la larve avec le jeune immature permet de résoudre, d’une fagon

certaine, plusieurs questions laissées douteuses par Krohn. Il présumait * que le lobe

operculigére de la larve devient le métapodium de Vadulte: ceci est confirmé par la

persistance temporaire, sur le métapodium, de la membrane pigmentée observée sur le

lube operculigére des larves agées (fig. 31, ji.’)—D’autre part Krohn ignorait si la

ventouse apparait avant ou aprés la réduction du velum: nos larves montrent bien que

le rudiment saillant de la ventouse (fig. 31 et 36, sw.) apparait avant la réduction du

velum.

4°.—Enfin, Videntité de ce jeune Hétéropode immature lui-méme, avec le genre

Carinaria présente une certitude presque absolue, par suite des faits suivants :—

(a) nucléus viscéral entitrement contenu dans la coquille ;

(2) coquille du jeune Hétéropode identique au “ nucléus” spiralé de la coquille des

Carinaria adulte (nucléus qui a été reconnu pour la 1** fois par d’Orbigny fF,

et depuis lors par divers auteurs {);

(d) Jes lames branchiales saillantes en petit nombre: chez le jeune (6 ou 7), comme

dans les Carinaria adultes (7 412) §;

(e) radula semblable ;

(f) nageoire métapodiale pigmentée, observée aussi par Lo Bianco (renseignement

inédit) sur les trés jeunes Carinaria.

5°.—Les Carinaria de |’ Atlantique sont demeurés longtemps mal connus; et autrefois,

un petit nombre d’espéces, seulement, étaient indiquécs de cet Océan :—

(a) OC. fragilis, Bory de St. Vincent, des environs du Cap de Bonne Espérance, dont

la coquille avait été détruite || ;

(b) C. atlantica, Adams, sans indication précise de localité { ;

(ec) C. Gaudichaudi, MacDonald, probablement des Antilles ** ;

* Krohn: ‘Beitriige zur Entwickelungsgeschichte der Pteropoden und Heteropoden, 1860, p. 36.

+ D'Orbigny : ‘ Voyage dans l’Amérique méridionale,’ vol. v. (1847) p. 161, pl. 11. figs. 14, 15 (C. punctata).

+ MacDonald: “On the Anatomy and Classification of the Heteropoda,” Trans. Royal Soc. Edinburgh, xxiii.

1862, pl. 2. figs. 4, 4'—Vayssiére: ‘Campagnes scientifiques,’ ete. pl. 4. fig. 54.—Smith: ‘ Report on the

Heteropoda,” Zool. ‘ Challenger’ Exped. pt. Ixxvii. p. 31.

§ Costa: Ann. d. Sci. nat. sér. 1, t. xvi. pl. 1.—Milne-Edwards : ibid. sér, 2, t. xviii, pl. 11. fig. 1.

|| Bory de St. Vincent: ‘ Voyage dans les + principales iles d’Afrique,’ vol. i. p. 141, pl. 6. fig. 4.

4 Adams and Reeve: ‘Zoology of the Voyage of the “Samarang” in the Eastern Seas.’—Cray : ‘ Figures of

Molluscous Animals,’ vol. iv. p. 100, pl. 239. fig. 2.

** MacDonald: “On the Anatomy and Classification of the Heteropoda,” Jor, cit. p. 18, pl. 2. fig. 4.

SECOND SERIES.—ZOOLOGY, VOL. X. 25

146 DR. P. PELSENEER—BISCAYAN PLANKTON:

Mais aucune forme n’avait été mentionée au voisinage de 1’ Europe, jusqu’en 1881, ott

ce genre fut dragué au N. de l’Espagne, par Expédition du ‘ Travailleur’*. Cepen-

dant, il y est relativement abondant, puisque l’Expédition du ‘ Challenger’ en rencontra

aussi au large du Cap St. Vincent et un peu plus au Sud +, ainsi que par 35° N. et 28° W.

Carinaria a coquille détruite ¢.

Puis, récemment, Vayssiére en a décrit trois formes provenant de péches de la

‘Princesse Alice’ dans l’ Atlantique Nord § :—

(a) C. Lamarcki, var. oceanica (peut-étre la méme que la derniére espéce citée du

‘ Challenger’) ;

(6) CO. Grimaldii (individu jeune) ;

Mais tous trois, ainsi que les spécimens du ‘ Challenger’ et du ‘ Travailleur’ proviennent

d'une région au 8.W. des Stations de la ‘ Research’ et comprise entre 39° et 45° N., et 14°

et 37° W., et l’on sait que les vents régnants de cette partie de Atlantique soufflent

de lW.

Les jeunes spécimens immatures ressemblent un peu a G. Grimaldii, Vayssiére ; mais

celui-ci n’est peut-étre que la forme jeune d'une esp&ce connue. Nous ne pouvons done

que rapporter larve et jeune immature simplement au genre Carinaria, sans pouvoir

indiquer a quelle espéce elle appartient.

IIL. THEcosoMEs.

10. PERACLIS TRIACANTHA (Fischer) ||. (Pl. 11. figs. 41, 42, 44; Pl. 12. figs. 43, 4:7.)

Cette espéce a d’abord été décrite, mais non figurée, par Fischer, d’aprés des coquilles

vides, sous le nom de Lmbolus triacanthus. Je Vai figurée depuis, également d’aprés

des coquilles vides, sous le nom de Limacina triacantha. Depuis, Tesch avait déja

pressenti que le vrai genre de cette forme est Peraclis§. L’expédition de la * Research ’

en a, la premiére, rapporté un animal complet, eta donné la démonstration expérimentale

de ’hypothése de Tesch: car l’examen de l’opercule seul montre déja que la forme en

question est bien un Peraclis (fig. 42); en effet, cet opercule est orbiculaire, multi-

spiralé, sénestre et & nucléus subcentral (au contraire, les opercules de Limacina sont

allongés, paucispirés et & nucléus latéral, placé vers la gauche de lanimal, c’est-d-dire

vers la fausse spire).

Distribution. Cette espéce est répandue dans tout le N. Atlantique.

11. PrRACLIS BREVISPIRA, sp.n. (Pl. 12. figs. 45, 46, 48, 49, 51.)

Coquille lisse, formée de 25 tours assez large, 4 spire trés peu saillante ; suture ornée

* Jeffreys: Ann. & Mag. Nat. Hist. ser. 5, vol. vi. p. 318.

+ Summary of the Results,’ pp. 117, 119.

+ Smith, E. A.: “ Report on the Heteropoda,” Zool. ‘Challenger’ Exped. pt. lxxvii. p. 37.

§ Vayssiére: “* Résultats des Campagnes scientifiques, etc.—-Mollusques Hétéropodes,” pp. 17, 18, 20.

| Fischer: “* Diagnoses d’espéces nouvelles de Mollusques recueillis dans le cours de l’Expédition scientifique

de V’Aviso le ‘Travailleur’ (1880, 1881),” Journal de Conchyliologie, t. xxa. 1882, p. 49.—Pelseneer: “ Report on the

Pteropoda,” Zool. ‘Challenger’ Exped. pt. ixv. 1887, p. 20, pl. 1. figs. 1, 2.

q Tesch: “The Thecosomata and Gymnosomata of the ‘Siboga’ Expedition,” Siboga-Expeditie, Monogr. lii. p. 19.

MOLLUSCA. 147

de petites lamelles rayonnantes, surtout visibles au dernier tour (fig. 51); bec colu-

mellaire pointu, et arqué, comme dans les autres espéces; ouverture large. Opercule

subcirculaire, multispiré, & spirale sénestre, & nucléus subcentral (fig. 49, op.); cet

opercule présente, plus nettement encore que l’espéce précédente, une zone obliquement

striée, dans la portion la plus centrale des tours de spire.

Outre les prises “ comparables” de la table (pp. 156, 157), cette espéce était péchée en

27 a (1250-0 fathoms).

Organisation et Relations phylogénétiques du Genre Peraclis.

Lorganisation du genre Peraclis était déja quelque peu connue, mais n’avait pu étre

étudiée que sur des espéces de trés petite taille +. Les dimensions beaucoup plus con-

sidérables de P. triacantha, recueilli par l’Expédition de H.ML.S. ‘ Research,’ permettent

de completer notablement les observations faites précédemment.

La téte est en forme de trompe saillante (fig. 41, /.), comme dans les autres Peraclis

et les Cymbuliide. Les deux tentacules sont symétriques (fig. 41, ¢.); l’orifice pénial

(pe.) est & droite et un peu en arricre du tentacule droit. Les nageoires ( fi.) ont leur

bord antérieur continu, sans le petit lobe tentaculiforme des grands Limacina (L. helicina

et L. antarctica).

Le bord du manteau porte, au cété droit, le méme appendice saillant et pointu, ou

“balancier,” que les autres Limacinide (da.). La glande palléale (bouclier) est

asymétrique, en ce sens qu’elle est plus développée au cdté droit, et obliquement orientée

(pa.g.)

L’ouverture de la cavité palléale n’est pas antérieure ni symétrique :—le bord dorsal du

manteau présente une échancrure vers la ligne médiane (fig. 41); 4 partir de cette ligne

médiane (fig. 41*), il est soudé au corps, sur la moitié gauche, de sorte que Pouverture

de la chambre palléale est située sur la moitié droite du corps.

Hors de cette ouverture palléale, fait saillie ’extrémité libre d'une branchie cténidiale

de structure “ plissée,” dont la pointe est dirigée en avant, vers la droite (g.). Le rein

est situé vers la gauche; et le cceur est 4 gauche du rein, et disposé & la maniére *‘ proso-

branche ” (comme tous les Limacinide, Peraclis a done une organisation dextre, dans

une coquille en apparence sénestre).

Le tube digestif offre les mémes caractéres que celui de Limacina (notamment les

quatre grandes plaques masticatrices du gésier) ; mais la radula (fig. 44), comprenant

11 rangées, offre une dent centrale beaucoup plus large que celle de ce dernier genre {, et

la pointe médiane de cette deut est beaucoup plus courte. Les dents latérales sont aussi

plus larges que dans Limacina (figs. 45, 1., 47, 48). Enfin les mandibules, qui sont

+ Pelseneer: ‘“ Report on the Pteropoda, part iii.,” Zool. ‘Challenger’ Exped. pt. Ixvi. pp. 11, 12 (1888).—

Tesch: “ The. Thecosomata and Gymnosomata of the ‘Siboga’ Expedition,” Siboga-Expeditie, Monogr. lii. pp. 17, 18

(1904).

+ Voyez, par exemple, Lovén: “ Malacozoologi,” Ofv. K. Vet.-Akad. Férhandl. 1847, pl. 3.—Sars: * Mollusca

Regionis Arctic Norvegiv,’ 1878, pl. 16, figs. 17, 13, 19.—Pelseneer; ‘‘ Mollusques,” Expédition antaretique belge |

pl. 6. fig. 74,

25 *

148 DR. P. PELSENEER—BISCAYAN PLANKTON:

iatérales, different aussi de celles des Limacina: elles sont formées de 5 rangées paralléles

de plaques rectangulaires, 4 bord rectiligne, avec chacune 3 dents en général, chez

P. triacantha (fig. 43) et 7 ou 8 dents chez P. brevispira (fig. 45); au contraire, chez

Limacina, ces plaques sont semicirculaires, a bord libre curviligne et imbriquées alterna-

tivement comme les tuiles d’un toit *.

Quant au systéme nerveux central, il présente les mémes dispositions générales qu’il

montre chez les Thécosomes, avec cette particularité que, de méme que les autres Peraclis

et les Cymbuliide, il posséde une chaine de trois ganglions viscéraux.

Si lon considére cette description en elle-méme, on la trouvera naturellement

insignifiante. Elle acquiert, au contraire, une certaine importance si on la compare aux

dispositions connues de l’organisation des autres Thécosomes et des Gastropodes.

Il est généralement admis que les Limacinidee sont les plus primitifs des “ Ptéropodes ”

‘thécosomes, les Cavoliniide et les Cymbuliide provenant de ces Limacinide par détorsion

(ce que j'ai indiqué en 1892 +, cest-i-dire bien avant que personne ait parlé de détorsion

chez les Gastropodes Euthyneura).

Mais, parmi les Limacinide, on n’avait pu déterminer en se basant sur un grand

nombre de caractéres la forme générique actuelle la plus archaique dans son organisation.

L’étude anatomique de Peraclis triacantha permet de le faire maintenant, avec

assurance.

En effet :

1°.—Tous les Thécosomes, par l’acquisition d’une symétrie extérieure (si commune dans

les Mollusques pélagiques) possédent une ouverture palléale symétrique ;—seul, Peraclis

montre encore une ouverture palléale latérale (& droite), comme dans les Tectibranches

Bulléens ;

2°.—Tous les Thécosomes sont dépourvus de eténidium (quelques Cavoliniidz ont, au

fond de la courte palléale, une branchie en fer 4 cheval, dont la nature cténidiale est

demeurée jusqu’ici obscure) ;—seul, le genre Peraclis montre un cténidium normal, du

type plissé, & extrémité libre saillante antérieurement, comme dans les Bulléens

archaiques ou “ Prosobranches,” tels que 4e/@on (comparer les figs. 50 et 52).

Ces deux caractéres essentiels ajoutés a celui de la dent centrale de la radula et & la

multiplicité des ganglions viscéraux, montrent que le genre Peraclis est le plus archaique

des Thécosomes actuels { et viennent ainsi confirmer la position attribuée dés 1888 § a ce

genre, tout & la base de l'arbre phylogénétique des “ Ptéropodes ” Thécosomes.

L’existence, parmi les Bulléens, de formes actuelles (telles que Acera), a larges

parapodies natatoires, a téte allongée, a appendice palléal correspondant au balancier des

Limacinidee, et & spire courte, permet d’inférer que d’autres formes plus anciennes encore

operculées et & spire nulle (comme il en existe 4 la fin de !’époque secondaire) ont pu

taire saillir une “ fausse spire ” au cdté ombilical et constituer ainsi les Limacinide ultra-

* Sars: ‘Mollusca Regionis Arcticew Norvegie,’ pl. 11. fig. 3, d.

+ Pelseneer: “ A propos de l’asymétrie des Mollusques univalves,” Journ. de Conchyl. 1892, p. 232.

+ ‘Pelseneer:.‘‘ Sur la forme archaique des ‘ Ptéropodes’ Thécosomes,” Comptes rendus Acad. Sci. Paris, t. exxxix.

1904, pp. 546-548, j

§ Pelseneer: “ Report on the Pteropoda,” Zool. ‘Challenger’ Exped. pt. Ixvi. p. 35.

a === ee Cl

MOLLUSCA. 149

dextres, c’est-i-dire & organisation dextre dans une coquille 4 enroulenent en apparence

sénestre.

12. Lrmacrna RETROVERSA, Fleming.

13. CLIO PYRAMIDATA, Brown.

14. Ciro cusprpata, Bose.

. CAVOLINIA INFLEXA, Lesueur.

IV. GYMNOSOMES.

16. FowLrertna Zerestos, gen. et sp. nn. (PI. 12. figs. 53-60.)

Cing adultes plus ou moins grands (la taille maximum est 8°5 millimétres) et deux

larves, proviennent de 6 stations.

Ces individus présentaient des aspects trés divers, dis a des états différents de

contraction et aux agents conservateurs variés (acide osmique, formol, aleool) employés.

De sorte que, & premidre vue, on pouvait supposer quiil y avait-li plusieurs formes

distinctes, et que leur identité 4 tous a été seulement reconnue par lexamen de la

radula.

En effet, un avait le corps et le pied gonflé (fiz. 53), tandis que sur les autres

Vextrémité du corps et la partie postérieure du pied, gardaient leur forme pointue et

offraient des nageoires trés contractées (figs. 54, 55); enfin, dans les différents spécimens,

la trompe était 4 des états variés d’évagination ou d invagination.

J'ai done représenté plusieurs de ces individus, afin de faire voir les caractéres essentiels

montrés sur des spécimens divers.

Du point de vue de la forme générale, le corps est terminé en pointe postérieurement

(figs. 53, 54), les viscéres ne s’étendant pas jusque-la. La peau est pigmentée; il n’y a

pas de branchie, ni postérieure ni latérale.

La ¢éte est courte, portant deux paires de tentacules (fig. 59).—Le pied présente un

lobe postérieur pointu postérieurement et assez allongé, sauf dans le plus grand spécimen

(fig. 52), ot il est trés contracté par l’enflure générale de la partie antérieure du pied.

L’anus et l’osphradium sont situés assez bien en arriére du pied (fig. 52, a. et os.). Les

nageoires sont amples.

La cavité buccale porte une seule paire d’appendices (ou céphalocdnes) latéro-ventraux,

ayant la méme structure que ceux de Clione, cest.i-dire portant de nombreuses petites

papilles serrées (fig. 59, ce.). La trompe est & peu prés aussi large que longue. La

mdchoire médiane (figs. 54 et 60), en forme de croissant, 4 concavité antérieure, est formée

d’environ 18 dents pointues, serrées les unes contre les autres. Les sacs 4 crochets, peu

profonds, renferment une quinzaine de crochets, plutdt courts (fig. 58). La radula

présente 17 4 20 rangs de 4.1.4, 5.1.5 ou 6.1.6, suivant l’Age (dans d’autres Gymnosomes

| Clione}, divers Aplysiens, et certains Pulmonés terrestres, le nombre des dents d'une

rangée transversale augmente aussi avec l’dge). La deat médiane est arquée, large,

150 DR. P. PELSENEER—BISCAYAN PLANKTON:

sans aucun denticule central, et pourvu d'une demi-douzaine de petits denticules de

chaque coté (fig. 57); les dents latérales sont coudées et terminées en pointe aigué.

Cette forme se distingue de tous les genres connus; je lanomme Fowlerina Zetesios

(en lhonneur du distingué zoologiste qui dirigea les campagnes de la ‘ Research,’ et de ce

dernier navire).

Fowlerina sécarte :

(a) des Pneumonodermatidee (Prewmonoderma, Cuvier; Dexriobranchea, Boas; Spongio-

branchea, d’Orbigny ; Schizobrachium, Meisenheimer), par l’absence de branchie et de

ventouses ;

(b) des Clionopsidee, par la brieveté de la trompe, la présence d’un lobe postérieur du

pied, l’absence de branchie ;

mandibule, par l’absence de branchie ;

(d) des Thliptodontide, par la présence d’une mandibule * et de eéphalocdnes ;

(e) des Halopsychide, par la présence de pigment dans la peau, de céphalocdnes et de

saes a crochets.

Au contraire, le nouveau genre se rapproche des Clionidz: par le corps pointu, sans

branchies et sans visceres jusqu’au bout; par le pied a lobe postérieur présent et pointu,

par la présence de céphalocénes et de dents centrales a la radula.

Cette famille Clionidee ne comprend que deux genres bien établis: Clione, Pallas, et

Paraclione, Tesch. Tous deux sont dépourvus de mandibule + et tous deux possédent

une dent radulaire centrale pourvue d'un denticule médian saillant.—Fowlerina est done

distinct de l’un et de l'autre.

Remarques sur les diverses Espéces de Clionide.

1°. Parmi les Clione :

(a) Clione limacina est dépourvu de chromatophores et poss¢de 3 paires de céphalocénes

et des sacs 4 crochets a dents longues ;

(b) Clione aurantiaca, Gegenbaur, C. longicaudata, Souleyet (Atlantique), et C. caudata,

MacDonald (Sydney), sont pourvus de chromatophores, de 2 paires de céphalocéues et

de sacs a crochets a dents courtes ;

cones, ses radula et sacs 4 crochets demeurant inconnus.

2°, Je suis porté a croire: («) que les Clione sub littera 6, se rangeront dans le genre

Paraclione, caractérisé par 2 paires de céphalocénes, a sacs a crochets courts, et a

chromatophores ;

(3) que C. punctata serait probabli ment un Fowlerina ;

* Kwietniewski: ‘ Contribuzioni alla conosceuza anatomo-zoologica degli Pteropodi Gimnosomi,” Rich. Lab.

Anat. Roma, vol. ix. p. 78.

+ Mais en une soi-disante “ Olio” MacDonald décrit une mandibule (“ On the Zoological Characters of the living

Clio caudata, as compared with those of Clio borcalis given in Systematic Works,” Trans. Roy. Soc. Edinb. vol. xxiii,

pl. 9. fig. 3d).

MOLLUSCA. 151

(y) que Clione limacina (et peut-étre C. antarctica, Smith) représente seul le genre

Clione.

V. LAMELLIBRANCHE.

17. Une larve indéterminable, avec 6 filaments branchiaux.

Occurrence. 34a. 25 to 0 fathoms. 1 specimen.

B. BLONOMIQUE.

Une partie des organismes recueillis appartiennent 4 la zone superficielle, s’¢tendant

jusqu’aux environs de 100 fathoms: c’est I’ “ epiplancton.’’ Une autre partie est propre

& une zone plus profonde, au-dessous des environs de 190 fathoms: c'est le ‘‘ méso-

plancton ” (Fowler).

1. EPIPLANCTON.

Tl comprend, 1°, des formes ¢z situ; C’est-d-dire eupélagiques ou holoplanctoniques ;

2°, des formes larvaires appartenant a des organismes benthoniques a l'état adulte, c’est-a-

dire des formes hémipélagiques ou mésoplanctoniques.

1°. Hupélagiques. Ce sont: A, Carinaria; B, la plus grande partie des Thécosomata

(Peraclis excepté); C, le Gymnosome Fowlerina, qui parait nyctipélagique.

2°. Hémipélagiques. Ce sont les larves de Gastropodes et de Lamellibranche, toutes

recueillies, d'une facon générale, entre 50 et 0 fathoms.—La détermination dun certain

nombre des larves de Gastropodes démontre quwelles appartiennent a des adultes abyssaux

(Columbella, Solarium, Natica, Coralliophila?, ete.), confirmant ainsi la supposition

faite il y a pres de cinquante ans par MacDonald *.

2. M&SOPLANCTON.

A ce groupe appartient seulement le genre Peraclis.

J’ai déja noté en 1888 7 que, dans la Méditerranée, ce genre habite en-dessous de

100 métres de profondeur.—Tesch a constaté que les 3 espéces de Peraclis prises par le

‘Siboga’ ne proviennent que d’une sew/e station (St. 243); mais il ne remarque pas qu’elles

sont obtenues dans une prise ¢rés profonde (tilet vertical de Hensen depuis 1000 métres).

De méme, de tous les exemplaires de la ‘ Research’ (18 stations), pas wn seul n’a €té

pris dans les nombreuses péches oi le filet était enfonecé seulement jusqu’a 50 brasses de

la surface (sauf 1 seul spécimen pris la nuit: 307). Tous les autres ont été recueillis

quand le filet avait été enfoncé jusqu’d 100, 150, 250, 350, 400, 1000 brasses ou

davantage.

Peraclis est done un genre caractéristique du mésoplancton ou de la faune zonaire, et

ne se rencontre jamais vers la surface. Il n’est connu jusquwici que dans les régions

tropicales ou tempérées et n’y constitue nullement une forme superficielle polaire qui

s'est enfoncée.

* Trans. Linn. Soc. vol. xxii. p, 241.

+ “Report on the Preropoda,” Zool. ‘ Challenger’ Exped. pt. Ixy. p. 30.

e 264

‘

LIBRARY}:

152

Vig.

Big. 2

—

ND oO B&W

wore OO ®

[ee]

www ©

29 09

DR. P. PELSENEER—BISCAYAN PLANKTON :

EXPLICATION DES PLANCHES.

PLANCHE 10.

Coralliophila (?), sp. A. Coquille larvaire, vue ventrale. x 21.

. Coquille larvaire, vue dorsale. x 21.

. Coralliophila (?), sp. B. Coquille larvaire, vue ventrale. x 21.

. Opercule, face extérieure. x 50.

. Columbella haliaéti, Jeffreys. Coquille larvaire, vue ventrale. x 21.

. Larve, vue dorsale. x 2].

. Larve, vue ventrale. x 21.

. Opercule, face extérieure. x 96.

. Une rangée transversale de la radule de la larve. x 590.

. Solarium? sp. Coquille larvaire, vue ventrale. x 50.

. Opercule, face extérieure. x 96.

. Natica (Lunatia) sp. Coquille larvaire, vue ventrale. x 21.

13.

. Larve hors de sa coquille, vue orale. x 20.

Une rangée transversale de la radula de la larve. x 810.

. Opercule, face extérieure. x 50.

. Premiére coquille larvaire d’un Lamellariide, vue ventrale. x 21.

. Vue latérale gauche de la méme. x 21.

. La larve hors de sa premiére coquillle, vue ventrale. x 21.

. Vue antérieure du velum étendu de Ja méme larve. x 21.

. Lamellaria, larve A. Premiére coquille larvaire, vue ventrale. x 21.

. Premiére coquille larvaire, cété gauche. x 21.

. Lamellaria, larve B. Premiére coquille Jarvaire, vue ventrale. x 21.

. Premiére coquille larvaire, cété gauche. x 21.

PLANCHE 11.

Lamellaria, \arve B. a larve, hors de sa premiére coquille larvaire, avec son velum ¢tendu ;

vue orale. x 40.

Lamellaria, larve A. Une rangée transversale de la radula. x 810.

. La méme larve, retirée de sa premiére coquille larvaire ; cété gauche. x 50.

. La méme larve, vue du cété droit. x 50.

. Lamellaria, larve B. Mandibules. x 250.

. Une rangée transversale de la radule de cette larve. x 450,

Carinaria sp. Coquille larvaire, vue ventrale. x 21.

21. Une larve Agée, hors de sa coquille, vue du cété droit. x 21.

. Un jeune individu immature; cété gauche. x 21.

. Nageoire métapodiale de ce jeune, vue ventrale. x 40.

4. Coquille larvaire, vue du cété columellaire. x 21.

. Coquille larvaire, cété apical. x 21.

. Larve hors de sa coquille, c6té gauche. x 21.

. Opercule de la larve, face extérieure. x 60.

. Vue orale du velum étendu de la larve. x 26.

. Une rangée transversale de Ja radula de la larve (dent centrale et dents latérale et marginale

gauches). x 450.

. Larve dans sa coquille, vue dorsale. x 21.

a i ie ie eed ee

Fig. 41

44. Une rangée transversale de la radula.

ee)

Peraclis triacantha.

4.6. Coquille, vue dorsale.

Fig. 47. Peraclis triacantha.

Vig. 48. Peraclis brevispira.

49. Ja coquille avec son opercule, vue ventrale.

MOLLUSCA.

Peraclis triacantha, Fischer, hors de sa coquille, vue dorsale.

42. Opercule, face extérieure.

x 50.

x 810.

PLANCHE 12.

Quelques dents de deux rangs de la mandibule.

Fig. 45. Peraclis brevispira, sp. n. Trois dents d’un rang de la mandibule.

x 21.

Une dent latérale de Ja radula, vue ventrale.

Une dent latérale de la radula, vue ventrale.

x 215

Fig. 50. Section sagittale schématique de Peracilis.

Fig. 51. Peraclis brevispira.

Vue apicale de la coquille. x 36.

Fig. 52. Section sagittale schématique de Act@on.

Fig. 53. Fowlerina Zetesios, gen. et sp. un., vue ventrale. x 9.

54. Vue ventrale d’un autre spécimen.

55. Vue ventrale d’un 3e spécimen, avec la trompe dévaginée.

56. Vue orale de la téte.

57. Une rangée transyersale de la radula.

58. Les crochets d’un sac a crochets.

59. Vue orale d’un spécimen.

60. Mandibule, vue ventrale.

Se Pale

ar Ae

se PHO),

x 96.

Ply,

x 3800.

20:

x 810.

x 450.

x 810.

<2:

Lettres communes aux trois Planches.

a. = anus.

a.l, = lame accessoire,

au. = oreillette.

ba. = balancier.

b.m. = masse buceale.

bo. = corps.

bu. = ganglion buccal.

c. = dent centrale.

ce. = céphalocdnes.

co. = muscle columellaire.

¢. = ceil.

pied.

fi. = nageoire.

fi. = nageoire métapodiale.

fg. = sillon pedieux.

g- = branchie.

g.0. = orifice génital.

h. = téte.

ho. = capuchon céphalique.

h.s. = saes a crochets.

in. = intestin.

k. = rein.

1, = dent latérale.

la. = larve.

fi..— tole.

m., m.' = dents marginales,

ma. = mandibules.

me. = métapodium.

mo. = bouche.

o. = ouverturede la coguille.

@. = wesophage.

o.l. = lobe pédieux operculi-

gere.

op. = opercule.

os. = osphradium.

p. = pénis.

SECOND SERIES.— ZOOLOGY, VOL. X.

pa. = manteau.

pag. = glande paliéale.

p.c. = chambre palléale.

pg. = ganglion pédieux.

pr. = trompe.

r. = rostre ventral de l’ouver-

ture de la coquille.

ra. = radula.

sh. = coquille.

si, = siphon.

su. = ventouse.

t. = tentacule.

v. = velum.

v.a. = lobe antérieur du velum,

v.d. = partie droite du velum,

vi. = masse viscérale.

v.p. = lobe postérieur du velum,

v.s. = partie gauche du velum.

154 DR. G. H. FOWLER—BISCAYAN PLANKTON :

NOTE ON THE DISTRIBUTION OF THE MOLLUSCA.

By G. Hersert Fower, B.A., Ph.D., PLS, F.ZS.

Tue chief thing noticeable about the distribution of these species is their rarity at

the actual surface. Out of seventeen distinguishable forms, only three were taken

at the surface, and all three were more plentiful at lower horizons of the epiplankton.

On the other hand, between 25 and 100 fathoms inclusive, despite the sparse

population as evidenced by the small number of total specimens, the captures were

numerous. Mollusca occurred :

At 25 fathoms

» 1

”? 100

», ul depths, 25-100 fms. ,, 72

EP)

in 75 per cent. of the hauls.

” 84 »” ”

vA?)

» ie oe) ”

3) 63 BE) ”

Few species occurred in sufficient numbers or with sufficient regularity to allow of

an accurate study of their distribution, and only one could be regarded as common at

the surface; but four were sufficiently plentiful to justify an analysis of their

occurrences *.

CARINARIA Sp.

Ate 10

fathoms, this

form occurred in

vas

1:0

RD \

0°5

0°6

per cent. of the

hauls, with

average specimens

per hour haul

Below 100 fathoms it occurred in no haul of the closing-net. We may fairly

conclude that this form was epiplanktonic, with an optimal horizon at 50 fathoms.

When tried on the time-depth table, there was no indication of vertical oscillation ;

again, when tested on a “day, night, and rain” table (compare supra, pp. 60, 61), it

was not obvious that the distribution was affected by light, darkness, or rain. But the

actual numbers captured were too small to allow of certainty on this point.

PERACLIS BREVISPIRA, Sp. 0.

At 0O

fathoms, this

species occurred in

SiS er)

5ON

o 0:0 \ oO -

del \ ee

~~ a =

emo |) ccs

oF | Se

i OOF. Vo ve 5

Spee | eS)

o's oo

Og 0:0 bu.

. o eo

a BRAN, i 2 eS

* As in previous analyses, the nine hauls with a small fine-meshed net haye been omitted, and the captures

multiplied by a time-factor (compare the second footnote on pp. 50 and 60).

MOLLUSCA. 155

It would seem from this table that the species was a member of the lower epiplankton,

and as it was taken also in three hauls with a closing-net out of seven such hauls

which contained Mollusca, and as it was not so plentiful above as to fill the mid-water

with dead specimens, it is very probable that it ranges also into the mesoplankton, as

low as the zone of 1000-750 fathoms.

CLIO PYRAMIDATA, Brown.

f= 4 n

At 0) Pe O \ o 0:0 \ = :

ae 3 =e

25 Se 16 a3 Se 0-1 = S

a5 Of Si

as ~ arp a4

50 =>) 53 a. IRS as

oe ore — oS Le og

ier, 27 | SS 02) eae

AS a al aa)

100 / 2 Ni oe rw 06 , =

5 3

This species, like the preceding, appeared to belong to the lower epiplankton, but

_ with an optimal horizon of 50 fathoms. It is possible that it extends below the

hundred-fathom horizon, having twice been taken in a closing-net.

CAVOLINIA INFLEXA, Lesueur.

At 0 12 | O-1 \

0:5 |

17a)

10 |

O01

Unlike the last, this species was captured at the actual surface, and seemed to show

an optimal zone of 75-50 fathoms. The single capture at 1500-1250 fathoms, in

the absence of any intermediate captures higher in the mesoplankton, can hardly be

taken to indicate any extension into the mesoplankton.

per cent. of the

hauls, with

fathoms, this

species occurred in

—

fen

average specimens

per hour haul

= “in

VALET

TPUBIGI[[oUeT

“80180 JOR

DULLIPNOT

“pavcayi

DIU OLD?

myppulsna OND |

myppuunthid — |

ong |

"DELIA O.Z Ib

DULIDULT

“p.rdsraang

SODMAT

“DYqUDIDUAZ

SyoD.laq

‘ds muumunmy |

‘q ‘ds

AD AUT

“premeypouyry |

Ae Pe screed ec TR.

ty ‘ds

prnyaunT

‘ds poupDAT |

‘ds wm.njogy |

“yanyny

nyjaquunjoy

T ‘ds

“(4) mprydoupy.oy

“y ‘ds

(2) nprydoupp.c

(S)

ie)

lpeal

(aa)

fe)

Haul.

whe 8 6 HS OS we OHS Veen oo Fe to Feo ee BESS o He Oe OVO ES OHBEDE Of OB oo mE

SAAS Oo HHH HH HID 19.15 1 ID OAMAMOSOOOHAARDAIAA DOA OID DOOM AANNIAIOONAN A HI19

Ti RN 0 08 29 09 aH NH HH HIG 1G 1S 1S IQA RBS RS BG BAB RA AAAS & os as Ge Od 09 09 3 Go 09 G9 ad 09 CD 00 09 OD OD

156

Depth in

fathoms

500—250

1500—750

2000—1000

75—O

25—0

MOLLUSCA.

a |

| Coralliophila (?),

Depth in

fathoms. Haul.

pyramidata,

relroversda.

triacantha.

sp. A.

sp. B.

Columbella

haliaéti.

sp. A.

Lamellariid.

brevispira,

macina

| Lamellaria,

| sp. B

eo | Carinaria sp.

Coralliophila (?),

Solarium sp.

Natica sp.

Peraclis

Pevaclis

‘avolinia

| Clio cuspidata.

| Lamellaria,

) 100—0

bo bo

reg i

i >

- —

Pew Ear!

a HST

fo =

req

[~¥

Hoe

36e 5a Hore | atelier. | tree ean een Van ices || 1863

150—0 36 f ae. |) gh {| oaaltee |) creel eee een een eee |! IL

150—50 21p

150—100 21n

200—0 21a |

200—100 21d

250—0 36h :

250—150 350 Peete |.) | ole | oa

300—0 36k

300—200 le

350—0 361 Pel etme | tl coef fe. |) an

400—800 21k :

500—400 21m

750—500 226

1000—750 23a oe || cee cerca Ream MCE ES cre icra [cscs foe's 4] ae

32 fF

B2k

1250—1000 24a

27 b

1500—1 250 25f

2000—1500 25e

? 266

SECOND SERIES.—ZOOLOGY, VOL. X.

zeteswos,

amellibranch

inflexa.

Fowlerina

Jarya.

| L

Trans. Linn. Soc., Ser.2. Zoou. Vol.X. Pu. 10.

Pelseneer.

2a,

pr hs

a rs

Ss ee

Steregc ceecee™

M.-P. Parker lith

Parker b Wee ing

P.Pelscneer ad.

BISCAYAN MOLLUSCA.

Trans. Linn. Soc., Ser.2. Zoon. Vol.X. Pu. IL.

“Pelseneer.

\36

. PILL

Parker & Wee te

BISCAYAN MOLLUSCA

Pelseneer. Trans. Linn. Soc., Ser.é. Zoon. Vol.X. Pu. 12.

MP. Packer lith

PrP dleeneer 4a. Parte fs Woot top

BISCAYAN MOLLUSCA.

[ aeons

BISCAYAN PLANKTON.

Part VIII—THE CEPHALOPODA.

By Wiu11Am E. Horus, Director of the Manchester Museun.

(Communicated by Dr. G. Hursert Fowrnr, F.L.S.)

(With 3 Text-figures.)

Read 7th Juue, 1906.

THE small collection of Cephalopods entrusted to me for examination by my friend

Dr. Fowler consisted entirely of young specimens, many too young to enable the species

to be determined with certainty, although the state of preservation was excellent.

Most of the examples I have submitted to my friend Dr. Pfeffer, of Hamburg, who

has made a special study of these immature forms, and I am greatly indebted to him for

giving me the benefit of his opinion.

The numbers preceded by “‘H” in square brackets refer to my own register.

ELEDONELLA sp.

Locality : 32 i, July 21, lat. 47° N., long. 7° 38’ W.; depth, surface to 100 fathoms ;

temperature, 52° to 64° F'.; one specimen [H 1066}.

This specimen is undoubtedly the young of some species of Hledonella or possibly

Japetella; the only noteworthy peculiarity it presents is that the arms of the second

pair are a little longer than those of the third. The suckers and the circumoral lip are

very dark, almost black. In the centre of the transparent arm is seen a slender black

Fig. 1.

thread, upon which is a fusiform swelling under each sucker (see fig. 1); this is

presumably the nerve-cord with a series of ganglia,

The present specimen extends the distribution of the genus to the Eastern Atlantic ;

SECOND SERIES.— ZOOLOGY, VOL. x. 28

»~ AS” *.

feb

160 DR. W. E. HOYLE—BISCAYAN PLANKTON :

the previously recorded localities have been as follows :—North of New Guinea (‘ Chal-

lenger,’ Station 220); off the Marshall Islands (‘ Albatross,’ Station 220, 1900); in the

Gulf of Panama (‘ Albatross,’ Stations 3366, 3415, and 3420, 1891) ; off the New England

Coast (‘ Albatross,’ Station 2099, 1883).

Chun (Verh. deutsch. zool. Ges. vol. xii. pp. 162-182, 1902) has expressed the opinion

that Hledonella and Bolitena are synonymous, but, so far as I am aware, he has not

published the grounds for this view.

ONYCHOTEUTHIS sp.

Locality: 816, July 20; lat. 47° 15’ N., long. 7° 41' W.; depth, surface to

50 fathoms; temperature, 52° to 64° F.; two specimens [H 1064, 1065].

The appearance of the larger of these two specimens, which measures a little over

5 mm. in length, is shown in the accompanying figure (fig. 2). Of special interest is

Fig. 2.

the small size of the fin in these immature stages, to which attention has already been

called by Pfeffer (“Synopsis cegopsid. Ceph.,” Mitt. naturhist. Mus. Hamburg, vol. xvii.

p- 159, 1900). The tentacles also are seen to be present only as minute rudiments,

contrasting strongly with the more developed arms.

TELEOTEUTHIS CARIBBHA (Lesueur).

Locality: 301, July 19; lat. 47° 14' N., long. 7° 58’ W.; depth, surface to

50 fathoms; temperature, 52° to 64° F.; two specimens [H 1062, 1063].

This species appears to be one of the commonest and most widely distributed of all

pelagic forms. It has been found pretty frequently both in the Atlantic and Pacific

Oceans, but the records from the Mediterranean require confirmation.

A character often noticeable in the young stages is a pair of conspicuous chromato-

phores, which appear as elongated spots in a latero-ventral position halfway along the

fin. These are not seen, however, in either of the examples now under notice ; they are

both very dark in colour, and perhaps the spots have been masked by a rearrangement

of the chromatophores.

THE CEPHALOPODA. 161

TELEOTEUTHIS sp.

Localities: 306, July 19; lat. 47° 14 N., long. 7° 58’ W.; depth, surface to

25 fathoms ; temperature, 54° to 64° F.; one specimen [H 1058].

35, July 24; lat. 47° 8’ N., long. 7° 54’ W.; depth, surface to 25 fathoms ;

temperature, 54° to 65° F.; one specimen [H 1070].

36k, July 25; lat. 47° 3’ N., long. 7° 55’ W.; depth, surface to 300 fathoms ;

temperature, 51° to 66° F.; two specimens [H 1071, 1072].

Doraropsis sp.

Locality: 34f, July 23; lat. 46° 43’ N., long. 7°15' W.; depth, 500 to 750 fathoms ;

temperature, 48° to 49° F.; one specimen [H 1069].

This specimen, which measures not quite 20 mm. in total length, has been identified

by Dr. Pfeffer, who possesses a fine series of young forms belonging to this genus.

Fig. 3.

Although it was much distorted I have restored it to the best of my ability, and give an

outline sketch (fig. 3), which shows some of its more striking characters. The body is

swollen and barrel-shaped, whereas the smallest example which has hitherto been

figured (Ficalbi, Monit. Zool. Ital. vol. x. 1899, p. 99) has the mantle tubular with

almost parallel sides.

CRANCHIA MEGALOPS, Prosch.

Localities: 24d, July 11; lat. 47° 5’ N., long. 7° 45' W.; depth, surface to

100 fathoms; temperature, 52° to 63° F.; one specimen [H 1057].

30g, July 19; lat. 47° 14’ N., long. 7° 58’ W.; depth, surface to 100 fathoms;

temperature, 52° to 64° F.; three specimens | H 1059, 1060, 1061).

98*

162 DR. W. E. HOYLE—BISCAYAN PLANKTON.

340, July 23; lat. 46° 43’ N., long. 7° 15' W.; depth, surface to 100 fathoms;

temperature, 52° to 65° F., one specimen [H 1067].

This species has been hitherto recorded from the neighbourhood of the Feroe Islands

and Greenland; I am not acquainted with any records so far south as those here given.

All the examples hitherto examined are very small, and it is highly probable that they

are immature and that the fully developed form has still to be discovered.

CRANCHIIDARUM gen. et sp. ?

Locality: 34d, July 23; lat. 46° 43’ N., long. 7° 15’ W.; depth, surface to

100 fathoms; temperature, 52° to 65° F.; one specimen [H 1068].

This is a small larval form measuring only about 3 mm. in total length; it is impossible

to determine the genus to which it should be referred.

EMBRYO.

Locality: 32m, July 21; lat. 47° 0! N., long. 7° 38' W.; depth 0 to 75 fathoms;

temperature, 52° to 64° F.

An embryo with yolk-sac attached was brought from this locality.

f 168 3

BISCAYAN PLANKTON.

Part IX.—THE MEDUSZ&.

By Evwarp 1. Browne, B.A., Zoological Research Laboratory,

University College, London.

(Communicated by Dr. G. Hersert Fowrer, F.L.S.)

(Plate 13.)

Read 7th June, 1906.

TABLE OF CONTENTS.

Page

HM ENOAUGEL OT Mayan Petevelo clave) cic cte v--'< s+ /« eva re «lcvelereelehafal olel checeatpemeeot by sft <6 164

Comparison with the Meduse recorded for the English Channel.......... 165

Previous Records for the Bay of Biscay .......- ss eee e ee eect teens 166

On Collecting and Preserving Medusze .. «1... .- sees eee cree seen eee 166

HypROMEDUSS,

ANTHOMEDUSE.

1. Margelis autummalis............0. cece cece ce eet e ecw enee ence 170

LEPTOMEDUSE.

Pei Delray tcifersjejare ats) lela ars «ic cicle«.« «sielerstevalel ofelsieisl Vetaba leh peisi=feleione\¢ 170

5), UUINE Fenton coer co CnO OO URE RDOR OD OO COUOCO rd 0c TpouC CU COuner 170

Hypropa.

4, Campanularia flexuosa .........0 sc sceeceveccceicceseescvenes 1A

TRACHOMEDUSR.

5. Trachynema eurygaster ......... ce cece cree eet e eee eee eenes aval

6. Colobonema sericcum ............cececcccce cere ceersseseneecs 172

7. Bhopalonema coeruleum ........... eee cece eee c eee eee erences 172

8. Homceonema platygonon ........ eee eee eee eee eet eet ene teeee 17

9, Aglantha rosed...... ccc eee ses rece e cere cereenns cess sbeerceres 175

MOH AC lAMtN a 8s, | 5210.0 «oie .0i 2 + v.0:0 0s bel siofola cen eleicialestecsiaie 404 0 0° 176

11. Aglaura homistoma ..........ceseer cece rece eect eer enserereees 176

NaRcomEDusz.

12. Cunoctantha fowleri, n. ap. ...... 2. cece cece nsec eee cee eee eeeeees 177

13. Pegantha 8p... cesses cece cece e eee ee cree cert et eceencceeces 178

WA. Solmundella sp... ccs. sec ceesaccemeceldisisessiacsssiercccccss 179

ScyPHOMEDUSZ.

15. Periphylla sp. 2.20.26. ecscresecces Gini peste Ma ors ooysn ee ele) 9/869 179

MGR CACOM AN DAITCM Gs va, ars on siepuiseie »eueln vel lel en ielulaietetnterepie «s'asesg tees 179

17. Pelagia? Ephyra stage ......-. se ceee see e ence eect ee ceeerees 179

List of Hauls with Indeterminable Specimens .........6-+s+ee sees eees 180

Explanation of Plate ......0... se cee ce eeee cence cnet en eeenecerenes 180

Bibliography ...0.0cccscccccececsceesutecedesesevececcsuecrecess 181

164 MR. EB. T. BROWNE—BISCAYAN PLANKTON :

INTRODUCTION.

Tur Medusze which Dr. Fowler collected during his expedition to the Bay of Biscay in

1900 were kindly handed over to me for examination. JI have worked through his

collection with much interest. After working several years on the medusoid fauna of

the British Isles, I was particularly anxious to learn something about the medusze

which live in the Atlantic beyond our hundred-fathom line. There have been many

expeditions to the deep water off our western coasts, but, for some reason or other, the

medusz have usually been forgotten, so that the records of capture beyond the hundred-

fathom line are rather scarce.

Dr. Fowler selected the northern side of the Bay of Biscay for his explorations,

and worked in the neighbourhood of latitude 47° N. and a little to the westward of

longitude 7° W., where he was able to let down his nets to 2000 fathoms. He made

138 separate hauls with tow-nets, and out of these I received specimens from 88 hauls.

I have been able to identify fifteen genera and ten species, but have failed to identify

specimens belonging to several different genera owing to their mutilated condition.

Unfortunately, nearly all the specimens taken in the deep hauls below 500 fathoms were

in bad condition, and several were quite unrecognizable.

The Trachomeduse predominated over all the other orders. Six genera were

recognized, and at least two more were present, but not in a recognizable condition.

- Three species formed about 85 per cent. of the specimens in the collection. These were

Aglantha rosea (42 per cent.), Aglaura hemistoma (27 per cent.), and Rhopalonema

ceeruleum (15 per cent.). Among the rarities I may mention Trachynema eurygaster,

which belongs to the fauna of the Mediterranean and the warm water of the Atlantic ;

Colobonema sericeum, one of the new deep-sea medusze discovered by the ‘ Valdivia’

in the Gulf of Guinea and the Indian Ocean; and some large adult specimens of

Homeonema platygonon. I expected to see at least one species of Liviope in the

collection, as the species of this genus are common and widely distributed over the

Atlantic; but their natural habitat is no doubt in the warm water. Occasionally they

do drift up the English Channel and along the west coast of Ireland.

The Narcomedusze were uncommonly scarce. Three genera were recognized, and at

least two more genera from out of the unrecognizable genera may be allotted to this

order. There is, however, a species which I believe has not hitherto been described.

It belongs to the genus Cunoctantha, and the species is named in compliment to

Dr. G. H. Fowler. It has a number of medusa-buds showing various stages of develop-

ment upon the pouches of the stomach. Other species of Cunoctantha and Ounina are

known to have medusa-buds; but at this stage the buds are really parasites, developing

sither directly or indirectly from the eggs of another medusa, or they may arise from

surious neutral amceboid cells such as those which Metschnikoff has described for Cumina

vroboscidea. The medusa-buds in this new species develop from outgrowths of the

walls of the stomach, presenting a straightforward case of asexual gemmation, such as is

found in some of the Anthomedusze.

The Scyphomedusze were also very scarce. The collection contains a single specimen

THE MEDUSA. 165

of Atolla, one of those meduse which are generally found at great depths and in cold

water ; and two early stages of a Periphylla, which is another medusa belonging to the

deep and cold zone.

The Anthomeduse are represented by a single species, namely, Wargelis autumnalis,

and the Leptomedusze by two species—Obelia lucifera and a Tima. The occurrence of

these medusz so far from the coast is no doubt due to a surface-drift. They are neritic

species which have gone astray. Fragments of the common littoral hydroid Campanu-

laria flecuosa were also taken in the tow-net.

CoMPARISON WITH THE MEDUS RECORDED FOR THE ENGLISH CHANNEL.

T should not have attempted a comparison with the medusz of the English Channel,

but for the results which have been obtained by an investigation of the plankton of the

Channel by the Staff of the Marine Biological Association at Plymouth. In 1903 a

series of quarterly cruises was begun in connection with the International Fisheries

Investigations. On these cruises series of tow-nettings are taken at definite stations,

some of which have been arranged to cover the entrance to the Channel.

Until the cruises began our knowledge of the Channel medusze was limited to those

found about twelve miles from shore, consequently nearly all the species which have

been recorded belong either to the Anthomedusz or Leptomeduse ; a list compiled for

these two orders gives about forty-five species. The Trachomeduse are represented by

only two species, namely, Liriope (Liriantha) tetraphylla, which occasionally comes in

shoals, and Gossea corynetes, which is rather scarce. The Narcomedusz are seldom

seen close in shore, and only one species (Solmaris corona) has been recorded.

The results obtained on the quarterly cruises for the years 1903, 1904, and the first

half of 1905 have been rather disappointing so far as medusz are concerned. Up to

the present Aglantha rosea is the only new addition to the list. I certainly expected to

see a greater increase of species among the Trachomeduse and Narcomedusze.

Gough (1905) in his account of the distribution of individual species in the Channel

says: ‘‘a comparison of the ranges of the single plankton-elements demonstrates the fact

that the oceanic species invade the Channel from the south-west, and become rarer as

they advance up the Channel.” Now Dr. Fowler’s stations lie in the track of medusze

invading the Channel from the south-west, so one would expect to find some of the

Biscayan species at the mouth of the Channel. For a comparison it is necessary to omit

the species which are known at great depths, and select only those which occur within

100 fathoms of the surface, as the depths of the Channel stations do not exceed

90 fathoms. We have then the following three species—Aglantha rosea, Aglaura

hemistoma, and Rhopalonema ceruleum—living within 100 fathoms of the surface in the

Bay of Biscay. Aglantha rosea has succeeded in entering the Channel, but the other

species have not. The records, up to the present, of the medusz taken at the entrance

of the Channel are distinctly in favour of the neritic forms. It appears that the oceanic

species only now and again drift within the Channel area.

166 MR. E. T. BROWNE—BISCAYAN PLANKTON:

PREVIOUS RECORDS FOR THE BAY OF Biscay.

In searching for records of medusze taken far away from shore in the Bay of Biscay I

have not been very successful, and have probably failed to find some that have been

made. In the Report by Maas (1904) on the collections made by the Prince of Monaco

there are three records for the Bay, namely, Zquorea forskalea, Agliscra elata, and

Atolla bairdii. These were all found on the southern side of the Bay, off the north

coast of Spain.

On COLLECTING AND PRESERVING MEDUS&.

The following methods for collecting and preserving medusz have been used by me

for several years. I publish them now with the hope that they may be useful and helpful

to naturalists who go abroad to collect plankton, or to make general collections, and,

finding some medusze, would like to know how to preserve them in fairly good condition.

I take into consideration the difficulties of working in a limited space on board a ship,

and also in having to get through the work with limited chemicals, vessels, and time. ©

On this account I omit methods more suitable for use in a properly equipped laboratory

on shore, and methods suitable for histological work.

Collecting Meduse.—A small flat hand-net made of bolting-silk is a useful implement

for catching medusze which can be seen swimming at the surface. Its use, however, is

practically limited to a small boat in sheltered waters. The medusz can be gently

lifted from the sea, and at once placed ina jar of sea-water without receiving any

damage.

Of tow-nets there are many kinds, some of which are responsible for the mutilation

of jelly-fish. The best kinds are those with a long cone-shaped net with a can attached

to the end. The bad kinds are those without a can at the end, and, ‘worst of all, are

certain kinds of closing-nets.

Asa guide, I give the size of the net which I generally use from a rowing-boat. It

has a circular mouth of 17 inches in diameter, and the net is about 5 feet in length,

gradually tapering down to 3} inches in diameter, which is the diameter of the zine can

attached to the end of the net. The nets are made of bolting-silk. Three nets form the

series, having respectively 30, 50, and 76 threads per inch. It is a mistake to use a very

fine-meshed net (about 150 threads per inch), unless one is seeking for diatoms and other

microscopic organisms.

The old-fashioned bag-shaped net, without a can at the bottom, is very liable, unless

pulled very slowly through the water, to damage delicate animals. The plankton

collects in a mass at the bottom of the net, and the pressure of the water against this

resisting mass crushes and mutilates the specimens.

The closing-nets used for deep-sea investigations, and worked by various mechanical

devices for opening and closing the mouth, are frequently made so that when the mouth

is closed the sides of the net come together. It appears to me that in hauling up the

net from great depths, especially when the ship is rolling, the sides of the net rub

together, and consequently the animals inside get seriously damaged. The medusze

THE MEDUS&. 167

taken in Dr. Fowler’s closing-nets were badly damaged, and many specimens had the

ectoderm and endoderm completely rubbed off. I would suggest that these nets be

fastened on to a series of hoops, so as to prevent the sides from coming together when

the mouth is closed.

The speed of towing the net is a very important matter when jelly-fish are wanted in

good condition. Asa rule, the net is towed too fast. When using my own net, of the

size mentioned above, from a rowing-boat, I know that the speed is about right so long

as I can comfortably hold the line on one finger. I once tested the pull with a spring

balance, and found that a pull of about three pounds was quite sufficient. If one tows

too fast the water banks up in front of the net and the animals shoot off to the sides,

and most of them pass outside the net.

When working a tow-net from a steamboat or a sailing-boat there is nearly always the

difficulty of regulating the pace of the boat. Even with the sails down or the engines

stopped a light breeze soon causes the boat to drift too fast, and then comes a strong

pull and a heavy strain which crushes the animals against the meshes of the net.

Dr. Fowler has just designed a tow-net to close as the pressure increases. Its design is

most ingenious, and its construction is so simple that there is no mechanism to get out of

order. I feel sure that this kind of net will be most useful to those who have to work

from steamboats or sailing-boats.

Preserving Meduse.—The wrong method, and the one which I believe from the appear-

ance of specimens is most frequently used, is to strain off the water and then place the

whole bulk of the plankton in a small bottle with a little formalin or alcohol. I have no

doubt that this method answers fairly well for animals which have a hard coat, or for

organisms such as diatoms; but it is ruinous for a medusa or for any other soft-bodied

animal. A medusa treated by this method is either squashed fairly flat, or is badly

contracted and out of shape. It is frequently mutilated and more or less macerated.

For the description and identification of medusz it is really necessary that some of the

specimens should be in good condition.

When the net is taken on board, the contents of the can should be poured into one or

more glass vessels; the medusze picked out and transferred to another glass vessel, which

must be perfectly clean and free from chemicals. At first the medusze are generally in

a contracted condition, and if preserved at once they die contracted. It is now best to

place the vessel aside for half an hour or a little longer, and, in the meanwhile, look

after the other members of the plankton. During the interval most of the meduse,

unless badly damaged, will have recovered from the shock, and will be seen slowly

pulsating and swimming about. If they should be crowded in a heap on the bottom of

the vessel, a slow stir round with a clean glass rod induces them to swim and expand.

“The medusze may be left in the vessel for two or three hours, if other work should be

more pressing and important, but an occasional stir round is beneficial. If the medusze

after the first half-hour look in a sickly condition, the sooner they are preserved the

better; but if in a healthy condition, there is no need to hurry over the preservation.

The simplest and quickest method for preserving either a few specimens or several

dozen is the pouring of diluted formalin into the sea-water; but the secret of success

SECOND SERIES.— ZOOLOGY, VOL. X. 29

168 MR. E. T. BROWNE—BISCAYAN PLANKTON:

lies in the manner in which this is done. The strength of the formalin should be about

5 to 10 per cent. (5 per cent. solution containing 5 ec. of formaldehyde, 40 per cent.

strength, and 95 cc. of water—either fresh water or sea-water may be used). The

quantity of formalin to be poured into the vessel containing the meduse depends upon

the quantity of sea-water in that vessel; it is better to add too much than too little.

About 10 ce. of formalin may be taken as about the mean quantity to add to 100 ce. of

sea-water.

The secret of success depends upon keeping the medusz in motion whilst the formalin

is being poured in. First stir the medusze very slowly and very gently round and

round with a clean glass rod. When all are in motion then begin pouring in the

formalin slowly and gently down the side of the vessel. Keep the medusze in motion

whilst the formalin is being added, and for at least two minutes after. The stirring is

very important, as it produces an even distribution of the formalin in the sea-water, and

the motion keeps the medusee off the bottom and allows them to die in a fairly good

expanded condition.

The medusze may be left at the bottom of the vessel for a few hours, and then they

must be transferred to a stronger solution of formalin. I store my specimens in a

10 per cent. solution of formalin, and change it at least once before finally sealing the

bottle. Another method is to pour a small quantity of 20 per cent. formalin, or even a

few drops of formaldehyde, into the bottle before finally storing it away. I firmly

believe in using plenty of formalin, as I have often found meduse in a state of

maceration when only very weak solutions have been used.

The method of simply adding formalin to the sea-water and giving a gentle stir round

is the quickest and easiest method for killing medusz. It gives fairly good results with

all kinds of medusz, but some species are more liable to contract than others. The

results are usually better when the medusz are in a fairly quiescent condition than

when they are vigorously swimming about.

Cocaine and Formalin.—TYo obtain meduse in a nice state of expansion and with the

tentacles stretched out it is necessary to use an anesthetic. This gives a little extra

trouble, but the results are well worth the trouble when really nice specimens are

wanted. ‘The anesthetic which I use is hydrochlorate of cocaine (soluble in water), in

a 1 per cent. or 2 per cent. solution, either in fresh water or in sea-water. As only a

very small quantity is used at one time, a bottle containing 100 ce. lasts a long time.

It is best to place the medusze in a glass vessel with just sufficient sea-water for them to.

swim in. Add a little cocaine (about 3 ce. of 1 per cent. cocaine for every 100 ce. of

sea-water) and stir gently with a glass rod to mix the cocaine with the sea-water. If

the medusz at the end of about 10 to 15 minutes have their tentacles expanded and they

do not contract when touched with the glass rod no more cocaine need be added; but if

still active, add a little more cocaine and repeat the stirring process. It is better to add

about half the cocaine at first, and gradually increase the quantity, than to give the

whole dose at once. An overdose usually causes a prolonged contraction. When the

meduse are anzesthetized stir them gently round and pour in the formalin solution. |

Keep on stirring whilst the formalin is being added, and for a minute or longer after.

THE MEDUSZ. 169

Specimens must not be left long in any solution containing cocaine, as it has a softening

action, causing the umbrella to lose its firmness and to become very limp.

When only one or two specimens have to be preserved a large watch-glass or a small

glass pot had better be used. Place in it the specimen with just sufficient sea-water to

cover, add two or three drops of cocaine. As soon as it is anzesthetized pour the

formalin or the fixing reagent quickly upon the specimen.

Formalin and Chromic Acid for Scyphomeduse.—Swall Scyphomedusee die fairly well

expanded when simply placed in formalin 10 per cent. in sea-water. The addition, after

the medusa is dead, of chromic acid is a distinct advantage. The chromic acid acts

upon the jelly and makes it tougher and more pliable. The yellowish-brown colour of

the chromic acid may be disregarded, as it gradually turns to a pale bluish-green

by oxidation. The strength of the chromic acid may be either 5 or 10 per cent., the

exact percentage is of little importance; just pour in enough to colour the formalin.

The mixture I use contains roughly about one volume of chromic acid 5 per cent.

solution, and nine volumes of formalin 10 per cent. solution.

After the specimen has been soaking several days in the chromic-formalin solution,

into which a little strong fermaldebyde must be daily poured and well stirred up, it

should be transferred, without washing, to a fresh 10 per cent. solution of formalin, and

then the bottle may be sealed and stored away. If, however, a few months later it

should be noticed that the formalin is becoming cloudy and milky, it means that

maceration is going on, and that an insufficient quantity of formalin was used. The

bottle should at once be opened, the fluid poured off, and a fresh solution of formalin

added.

The successful preservation of Scyphomedusz, especially the large ones, greatly

depends upon using plenty of strong formalin, so that the animal may become thoroughly

saturated. It must be remembered that a jelly-fish contains an enormous quantity of

fluid, all of which has to be replaced by the formalin solution. Hence the necessity of

keeping up the strength of the solution and the stirring.

Damage done by Air-Bubbles in Tubes and Bottles—Although great care is some-

times taken in preserving medusie, yet no care is taken in properly storing the specimens

for travelling. I have frequently opened tubes and bottles containing specimens in an

excellent state of preservation, but broken in fragments. The damage has been done

after the specimens went into the bottle, and not by the tow-net. There is nothing

more disastrous to delicate animals, like medusze, than an air-bubble rolling about in a

narrow tube, or a large air-space in a bottle which is subject to the rolling of a ship or

the shaking in a railway-train. Bottles with large hollow glass-stoppers are frequently

responsible for the destruction of specimens ; such stoppers should be plugged-up with

paraflin-wax. If tubes are being used a plug of cotton-wool should be placed in. After

_the specimens are in the tube, fill it to the brim with formalin, and then push in a tight-

fitting plug of cotton-wool, which has been previously saturated with formalin, taking

care not to introduce an air-bubble. The tubes can either be stored in a large jar of

formalin, or corked and sealed with paraflin-wax.

When bottles are used, the common 1 oz. to 4 oz. sizes, with the best corks, are most

29*

170 MR. E. T. BROWNE—BISCAYAN PLANKTON:

suitable for small medusze; I prefer them for travelling purposes to glass-stoppered

bottles. The formalin does not dissolve out the tannin from the cork, as alcohol does.

It is a mistake to pack small specimens in cotton-wool, they only get crushed by the

weight of the wool. Simply fill the bottle to the brim with formalin, and gently

hammer in the cork with a light wooden mallet. With a little care a large air-bubble

can be avoided, and a tiny one is fairly harmless, provided that it cannot touch the

specimen. As a precaution against leakage and evaporation it is advisable to seal the

cork, when it has become quite dry, with hard paraffin-wax.

HYDROMEDUSZ.

Order ANTHOMEDUS/.

Fam. MarRGELIIDS.

MARGELIS AUTUMNALIS (Hartlaul), 1897.

Bougainvillea autumnalis, Hartlaub, 1897, p. 465, Taf. 15.

An adult specimen. Umbrella about 2°5 mm. in diameter. Gonads large. About

six to seven tentacles on each of the four perradial bulbs.

Occurrence: 25 to 0 fathoms. 33 g (1 specimen).

Distribution —North Sea; English Channel; west coast of Ireland.

This species belongs to the neritic fauna; its hydroid is at present unknown.

Order LEPTOMEDUS &.

Fam. EUCoPID 4.

OBELIA LUCIFERA (Forbes), 1848.

Thaumantias lucifera, Forbes, 1848, p. 52, pl. 10.

Six specimens, none of which have ripe gonads.

Occurrences: Surface, 21 ¢ (1 specimen); 23 0(2), 23d (1), 24g(1). 100 to 0 fathoms,

25 d (1).

This species belongs to the neritic fauna. It is at present uncertain to which hydroid

species Obelia lucifera belongs.

Tima sp. ?

Description.—The umbrella is thick, moderately curved, and more than twice as broad

as high. The velum is narrow. The stomach is very small and flat ; it is situated upon

a broad, short, somewhat cone-shaped peduncle. The mouth is small and has a folded

margio. Four narrow radial canals. Tke gonads are immature, and are situated upon

the radial canals, probably extending along nearly their whole length. About

THE MEDUSA, ia.

24 tentacles, with long, narrow, tapering basal bulbs. About 5 or 6 marginal bulbs

between every two tentacles. One or two cirri between every two bulbs. One sensory

vesicle between every two bulbs.

Size: Umbrella 25 mm. in width and 10 mm. in height.

Occurrence : 50 to 0 fathoms. 36 d (1 specimen).

The specimen is rather macerated. I believe, from the appearance of the gonads, that

the medusa has only reached an intermediate stage of development.

Order HYDROIDA.

Fam. CAMPANULARIID.

CAMPANULARIA FLEXUOSA, Hincks, 1868.

Campanularia flexuosa, Hincks, 1868, p. 168, pl. 33.

A few small pieces of this hydroid were taken in the surface tow-nets. The pieces are

from the upper part of a colony, and look as if they have only just been broken off. The

hydranths are well expanded, and a few gonothecz are present.

Campanularia flexuosa is a fixed hydroid and belongs to the littoral fauna. Its

occurrence so far from its usual habitat is probably due to seaweed drifting away from

the coast.

Occurrences: Surface. 24 f, 249.

Order TRACHOMEDUS &.

Fam. TRACHYNEMID2.

TRACHYNEMA EURYGASTER (Gegenbaur), 1856,

Sminthea eurygaster, Gegenbaur, 1856, p. 245, Taf. 9.

Marmanema mammeforme, Haeckel, 1879, p. 262, Taf. 17,

Sminthea eurygaster, Metschnikoff, 1886, p. 244, Taf. 1,

Trachynema eurygaster, Maas, 1893, p. 12.

There are ten specimens, of which three are in fair condition. They resemble very

closely the figures given by Gegenbaur and Haeckel.

The umbrella of the largest specimen measured 4.5 mm. in width and 2 mm. in height.

The velum is about 1 mm. in width. There are eight tentacles (all the specimens have

the tentacles broken off near to the base), one opposite each of the eight radial canals.

The gonads are very small, globular in shape, and are situated quite close to the margin

ot the umbrella, one on each radial canal.

Occurrences: 100 to 0 fathoms. 35d (1 specimen), 36e (2).

150 to 0 fathoms. 36 / (4).

250 to 0 fathoms. 36h (2), 362 (1).

Distribution. Messina ; Canary Is. ; off the north coast of Brazil in South Equatorial

stream.

This is a rather rare species.

Expedition.

It was taken only once by the ‘ National’ Plankton

172 MR. E. T. BROWNE-—BISCAYAN PLANKTON: -

CoLOBONEMA SERICEUM, Vanhoffen, 1902, p. 56, Taf. 9, 12.

There is one specimen. The umbrella, owing to the firmness of the jelly, has retained

its shape very well, but the preservation is by no means good.

The umbrelia is highly curved, about 18 mm. in height and in width; the velum is

broad, about 4mm. The stomach is very short; it is contracted, and forms simply a

narrow ring about 2 mm. in diameter. LEight radial canals. There are indications of

gonads extending along the radial canals, as figured by Vanhdffen, but the canals are in

a macerated condition, and nearly all the circular muscles on the sub-umbrella have

disappeared. There are 32 tentacles, all of which are broken off close to the base. The

per-canal (opposite the radial canals) and ad-canal tentacles are very much larger than

the inter-canal tentacles; the latter are just beginning to develop. The root of a

tentacle resembles Vanhéffen’s figure (Taf. 12. fig. 42). Seuse-organs were searched for,

but were not found.

Occurrence: 250 to 0 fathoms. 36% (1 specimen).

Distribution —This species is one of the new deep-sea medusz discovered by the

‘Valdivia.’ It was found off the west coast of Africa from the Gulf of Guinea to the

south of Cape of Good Hope (lat. 42° 8.), and also widely distributed over the Indian

Ocean. It was taken in open vertical nets worked from the depth of about 1600 to

650 fms., once in a closing-net working between 820 to 500 fms., and once in a trawl at

about 3850 fms. Its occurrence in the Bay of Biscay considerably extends the area of

its distribution.

I have associated the Biscayan specimen with Vanhéffen’s species because the latter

was also found in the Atlantic. Maas, however, has described a Colobonema (C. typicum ?)

found by the ‘Siboga’ Expedition in the Hast Indies (Straits of Makassar; off Timor,

Ceram, and other islands), and taken at a depth of about 1350 to 230 fms. He suggests

that it is probably identical with Colobonema sericeum and with Homaonema typicum,

Maas, 1897. This latter species was found in the Pacific, off Costa Rica, and in the

Gulf of California. I think that the specimens of Colobonema collected on the ‘ Valdivia’

and ‘ Siboga’ Expeditions probably belong to the same species, but am rather doubtful

about their connection with Homeonema typicum.

RHOPALONEMA C@&RULEUM, Haeckel, 1879, p. 264, Taf. 17. figs. 3-6.

There are about seventy specimens, but out of these only about a dozen are in fairly

good condition. Many have the margin of the umbrella in such a bad state that the

tentacles, cirri, and sense-organs have completely disappeared.

Description based upon the largest Specimens.—The umbrella is fairly highly curved,

with a small somewhat conical top-knot. There is a slight variation in the shape of the

umbrella and in the shape of the top-knot. The figure by Haeckel (Taf. 17. fig. 3)

gives a fairly good idea of the shape of the umbrella, but most of the Biscayan specimens

have a slightly more rounded umbrella. The umbrella is broader than high. Among

the larger specimens the height remains fairly constant, about 6 to 7mm. The width

is variable, 7 to 10 mm. The ex-umbrella is marked with radial furrows, which may be

THE MEDUS2. 173

due to shrinkage. The velum is very broad, about 2 to 2°5 mm. in width. The stomach

is cylindrical in shape when stretched out, and is about half the length of the umbrella-

cavity. The mouth has four small lips. The gonads are upon the eight radial canals,

and occupy, as a rule, the central third portion of the canals, but they vary slightly in

position, being in some specimens a little nearer the stomach, in others a little nearer

the margin of the umbrella. The gonads are at first linear, but when mature they

become cylindrical. Their length is variable, about 1 to 3mm. There are eight per-

canal tentacles, 8 inter-canal cirri, and 16 ad-canal cirri; 16 sense-organs (two in each

octant, one next the inter-canal cirrus and one next the per-canal tentacle), but perhaps

more.

Size: Umbrella up to 10 mm. in width and 7mm. in height. (Most of the specimens

about 6 to 8 mm. in width.)

Early Stages: There are a few early stages. One of these measures 2 mm. in diameter.

It has 8 per-canal tentacles, 8 inter-canal cirri, and a sense-organ next to the inter-canal

cirrus. No gonads visible.

Sense-organs.—The search for sense-organs with a moderate high-power lens has not

yielded very definite results. When sense-organs could be found I usually saw the

one next to the inter-canal cirrus. In three specimens I clearly saw a sense-organ

next to the per-canal tentacle, and a few other specimens also showed a cell which some-

what resembled a sense-organ in a similar position. In one specimen, and in one octant

only, I saw three sense-organs; as it only occurred once, it may be an instance of

numerical variation. It may, however, be simply normal development, in which case

the species would probably have four sense-organs in each octant. The sense-organ

next the inter-canal cirrus appears, from its size and frequency in the specimens, to

develop first, and then next in order comes the one near the per-canal tentacle. The

latter is usually very small in size and very hard to see.

Occurrences: Surface. 23 b (1 specimen).

25 to 0 fathoms. 300 (3), 31a (1).

50 to 0 fathoms. 21g (1), 25g (1), 25k (5), 26 @ (2), 830d (1), 30 Z (8),

310 (4), 36d (1).

75 to 0 fathoms. 32m (2), 35a (1), 35e (1), 864 (1).

100 to 0 fathoms. 246 (5), 24d (4), 24e (2), 25d (2), 80h (1), 32d (4),

324 (2), 32n'(1), 32p (4), 33d (4), 340 (1),

34d (2), 35 b (2), 85d (4), 35 x (2), 366 (2).

200 to 0 fathoms. 36g (1).

250 to 5 fathoms. 36h (1).

350 to 0 fathoms. 36 / (1).

This species was evidently occupying a zone between 50 and 100 fathoms, and there is

no proof that it occurred at a greater depth.

Distribution —Canary Islands.

The identification of the species belonging to the genus Rhopalonema appears to me to

be becoming rather difficult. I do not think that I shall be going far astray in assigning

174 MR. E. T. BROWNE—BISCAYAN PLANKTON:

the name Rhopalonema ceeruleum to the Biscayan specimens, for they come nearer to

this species as described and figured by Haeckel than to any other species.

Maas (1905) has described and figured a Rhopalonema which was taken in deep water

(500 to 1350 fms.) by the ‘Siboga’ Expedition in the East Indies, under the name of

Rhopalonema cweruleum, and also states that it is identical with Rhopalonema funerarium

described by Vanhoffen from the ‘ Valdivia’ collection. The figures given by Vanhéffen

and by Maas do not show the top-knot on the umbrella, which is always present in my

specimens. Their figures also show longer gonads, which come near the margin of the

umbrella. They find four sense-organs in each octant. Their specimens are of larger

dimensions than those from the Bay of Biscay.

HOM@ONEMA PLATYGONON, Maas, 1893.

Homeonema platygonon, Maas, 1893, p. 15, Taf. 1; Browne, 1903, p. 21, pl. 2.

There are four specimens; one of them I identified as Homaonema platygonon, but

about the other three I was uncertain. They appeared to me to belong to this species,

but showed characters of the genus Haliscera. Under these circumstances I considered

it advisable to consult Prof. Maas and let him see the specimens; he informed me by

letter that all the specimens belonged to one species, namely, Homeonema platygonon.

As Prof. Maas intends revising the species of the genera Homaonema and Haliscera,

lam glad that these specimens were sent to him.

Notes on the specimens :—

(a) This specimen resembles very closely that shown in Maas’s figure, but it is at an

earlier stage of development. The umbrella is hemispherical, nearly 2 mm. in

width and J] mm. in height. The velum is about 0°5 mm.in width. The stomach

is circular, about 0°75 mm. in diameter. There are seven radial canals, instead of

eight, which is the normal number. The gonads are just beginning to appear

upon the radial canals, adjacent to the stomach. About 5 to 6 tentacle-stumps

in each octant. Four sense-organs.

(0) This specimen is not in very good condition. The umbrella is about 3 mm. in height ;

it has a conspicuous cone-shaped mass of jelly, which is quite half the length of the

umbrella, above the flat top of the stomach. ‘The cells of the radial canals are

in a macerated condition, and I cannot distinguish the generative cells with

certainty. The gonads may be regarded as quite immature.

thick. The velum is very broad, exceeding 1 mm. in width. The stomach is

circular, 2mm. in’ diameter, with a flat top. The mouth is circular, and is

expanded nearly to the periphery of the stomach. Eight radial canals. The

gonads are upon the radial canals, adjacent to the stomach. In this specimen,

which is a female, each ovary is a semicircular swelling containing a few large

ova. From five of the radial canals the gonads have disappeared, and from the

appearance of the canals the ova have evidently been shed. About 10 to 12

THE MEDUS. 175

tentacle-stumps in each octant. Hight sense-organs, one in each octant; they

are external, fairly large, and have a short stalk.

Size: Umbrella about 3 mm. in width and 2°5 mm. in height.

(d) This specimen is in rather bad condition. It is about the same size and probably

about the same shape as specimen c. It shows the lower wall of the stomach in

an expanded condition, and also shows that the mouth is capable of closing. I

presume the specimen to be a male with unripe gonads, which are situated upon

the radial canals quite close to the stomach. The radial canals in the proximity

of the gonads are sac-like, and upon the outer wall of the sac a gonad is situated

as a semi-globular swelling. Two sense-organs were found in one octant.

Occurrences: 100 to 0 fathoms. 24e (1 specimen).

200 to 0 fathoms. 36 9 (1).

250 to 0 fathoms. 36h (1).

390 to 0 fathoms. 36 / (1).

Distribution—Between Iceland and Greenland, lat. 60° N., ‘National’ Plankton

Expedition ; Norway, Skjerstadfjord, within the Arctic Circle, 280 to 0 fms. and 270 to

0 fms.; Byfjord, near Bergen, 55 to 110 fms.

Our knowledge of the distribution of this species is at present rather limited. It seems,

however, to like rather cold water, and prefers to live below 100 fathoms.

AGLANTHA ROSEA (Forbes), 1848.

Circe rosea, Forbes, 1848, p. 34, pl. 1.

Aglantha rosea, Browne, 1898, p. 833, pl. 49; 1903, p. 23.

This species is one of the commonest forms in the collection. There are nearly

200 specimens; about half of them are in fair condition, but only a very few are

perfect.

The smallest specimens are a little less than one millimetre in length and are quite

early stages. Most of the specimens are about 5 to 7 mm. in length, and a few are

larger. The umbrella of the largest specimen measured 11 mm. in length and 5 mm. in

width. A specimen 10 mm. in length and 5 mm. in width has about 72 tentacles, and

one measuring 6 mm. in length and 3°5 in width has about 64 tentacles.

In the search for sense-organs I found a few specimens which possessed sense-organs

in adjacent octants, and also had the satisfaction of counting eight sense-organs in one of

the largest specimens. This established beyond doubt the identification of the species.

It is only in the most perfect specimens and in those with the margin of the umbrella

nicely expanded that more than half the sense-organs are likely to be seen. The sense-

organs, like the tentacles, are usually broken off in the tow-net, and even when present

their minuteness renders them hard to find if the margin of the umbrella is curled

inwards.

Some of the larger specimens have gonads about 1 mm. in length, and many of the

smaller specimens (about 5 to 7 mm. in length) show the gonads forming on the radial

canals at the base of the peduncle of the stomach.

SECOND SERIES.—ZOOLOGY, VOL. X, 30

176 MR, E. T. BROWNE—BISCAYAN PLANKTON :

Occurrences: Surface. 22d (1), 22e (4), 23 6 (9), 23d (1).

50 to 0 fathoms. 2149 (2), 307 (18), 310 (6), 32a (1), 32h (1),

33.¢ (1).

75 to 0 fathoms. 30, (5), 32g (2), 35 (1).

100 to 0 fathoms. 21h (26), 217 (20), 22 a (32), 240 (2), 24d (16),

24e (4), 25 d (5), 30g (2), 80h (1), 820 (1),

32 p (1), 83d (2), 34d (1), 35 b (1), 85 f (1),

36 b (1), 36 e (2).

150 to O fathoms. 386 f(1). -

150 to 50 fathoms. 21 p (7).

200 to 0 fathoms. 36 g (1).

200 to 100 fathoms. 21 0 (4), 35 m (1).

250 to Ofathoms. 367 (1).

300 to 200 fathoms. 21 ¢ (1).

500 to 400 fathoms. 21 m (2).

750 to 500 fathoms. 22 b (1).

1000 to 750 fathoms. 28 a (1).

1250 to1000 fathoms. 24 @ (1).

It appears from the number of hauls in which Aglantha occurs that it was chiefly

inhabiting the lower part of a zone between 50 and 100 fathoms. It was scarce at or

near the surface, and also at depths below 100 fathoms.

Distribution —Norway ; Shetland Is.; North Sea; Feeroe Channel; west coast of

Ireland; mouth of the English Channel.

AGLANTHA sp. B.

There are six specimens of an Aglantha which I have isolated on account of the radial

canals being twice the width of the canals of Aglantha rosea, and also because the

umbrella is about as broad as long. These specimens are without gonads, and the

sense-organs could not be found. I think that they must be young stages of another

species, perhaps Aglantha digitalis. The largest specimen measured 7 mm. in length

and width.

Occurrences: 750 to 500 fathoms. 220.

1000 to 750 fathoms. 23 a.

1250 to O fathoms. 27 a (trawl).

1500 to 750 fathoms. 30 a (trawl).

AGLAURA HEMISTOMA, Péron et Lesueur, 1809.

Aglaura hemistoma, Haecke), 1879, p. 275, Taf. 16; Maas, 1893, p. 25, Taf. 1; Mayer, 1900, p. 65,

pl. 25; Vanhdffen, 1902, p. 78; Mayer, 1904, p. 26, pl. 4; Lo Bianco, 1904, p. 55, fig. 138.

The collection contains about 130 specimens, a few of which are in good condition.

The umbrella of the largest specimen measured about 3 to 3°5 mm. in height and about

asl

—

THE MEDUSZ. iT

2mm. in width. The shape of the umbrella is similar to that in the specimens figured

by Maas. The peduncle of the stomach is very short, about one-sixth the length of the

umbrella. The gonads are upon the peduncle, just above the stomach. At first the

gonads are little oval or globular swellings, and as they increase in size they become

cylindrical and hang down. A specimen 3 mm. in height had cylindrical gonads about

1:25 mm. long and 64 tentacles. Only one specimen was seen with tentacles, and it had

a nearly complete set in a closely contracted state; all the others had only the roots or

stumps of the tentacles remaining. )

Occurrences : Surface. 217 (1), 23 6 (1), 32. (2), 33.4 (8).

25 to 0 fathoms. 300 (4), 30 m (24), 31 a (12), 82 d (1), 349 (2), 35 w (3).

50 to 0 fathoms. 30d (12), 307 (3).

75 to 0 fathoms. 30 f (13), 32 9 (1), 320 (2), 35a (2), 35¢ (5), 35 y (3).

100 to 0 fathoms. 21% (1), 30g (14), 30% (16), 34d (1), 35f (2),

35 x (1).

It was occupying a zone extending from the surface down to 100 fathoms.

Distribution.—The tropical and subtropical waters of the North Atlantic and Indian

Oceans.

Aglaura hemistoma is widely distributed over the warm-water area of the North

Atlantic, and it also occurs in the Mediterranean. The ‘ National’ Plankton Expedition

did not find it north of latitude 45° N.

Order NARCOMEDUS.

Fam. CUNANTHIDA.

CUNOCTANTHA FOWLERI, nova species. (PI. 13. figs. 1 & 2.)

Description of Species.—The umbrella is watchglass-shaped, about three times as broad

as high. The stomach is circular, with eight lateral pouches extending to the margin of

the umbrella. Upon the pouches of the stomach there are medusa-buds, which are not

parasitic. Eight rather long tentacles. Five sense-organs upon each of the eight

marginal lobes.

Size: Umbrella about 4 mm. in diameter.

Occurrence: 50 to 0 fathoms. 310 (1 specimen).

There is only one specimen, which is in fairly good condition. The umbrella is

slightly crumpled and its margin is curled inwards. The velum has broken away and

only slight traces of it remain. The mouth is expanded and circular in shape. The

pouches of the stomach are broadest in the middle and become narrower as they approach

the margin of the umbrella. Upon the pouches of the stomach there are one to three

medusa-buds showing various stages of development. There are no gonads present, but

they should appear at a later stage, after the gemmation-period is over. The length of

the tentacles is about equal to the diameter of the umbrella, and they taper out to a

fairly fine point. ‘The peronial groove is broad and shallow, and contains a band (the

peronium) of nematocysts, which broadens out at the bases of the tentacles. The lobes

30*

178 MR. E. T. BROWNE—BISCAYAN PLANKTON:

of the umbrella are slightly rounded, but their shape is not very well seen owing to the

curling inwards of the margin. Some of the sense-organs are broken off, but many

remain. Their number, however, is ascertainable by the narrow rows (the otoporpe) of

nematocysts which extend a little way up the ex-umbrella side of the marginal lobe.

Each otoporpa is in continuity with a minute bulb containing nematocysts on the

margin of the umbrella, and upon every bulb a sense-organ is situated.

Development of the Medusa-buds.—The medusa-buds form a nearly complete series

which shows very well the course of their development. ‘They resemble in external

appearance the figures given by Maas (1892) and by Chun (1894) for the development

of a Cunina-bud.

Two adjacent pouches of the stomach were removed and cut into sections. The

sections show that a bud begins as a hollow outgrowth of the wall of the pouch (fig. 2,

B', B). Sections were also cut of a later stage; its shape and structure agree with the

figures given by Maas (1892, fig. 23) and by Chun (1894, fig. 64, v.).. It is evident from

these sections that the buds are developing directly from the wall of the pouch and that

they are not of a parasitic origin.

The largest and most advanced medusa-bud shows the outgrowth of the eight

tentacles, the velum, the eight marginal lobes, and two sense-organs upon each lobe.

This medusa-bud was removed from the pouch for examination, and an opening

(fig. 1, O.) into the cavity of the pouch was found.

So far as I know, no species of Cunoctantha or Cunina have hitherto been described with

medusa-buds developing directly from the wall of the stomach or its pouches. Brooks

(1886), in his account of the life-history of the Narcomeduse, says: ‘‘ No one has shown,

by careful examination, that any adult Cwnina produces buds from its stomach or from

any other part of its body, and there is every reason for believing that the Cunina larvee

found in their stomachs are parasites, like those found in Turritopsis and in Geryonids,

and that the Cunina larva found in the stomach of an adult Cunina does not necessarily

belong to the same species with the adult.”

A medusa bearing medusa-buds is usually at an early or intermediate stage of

development, and does not show all the characters found in the fully grown adult with

gonads. Cunoctantha fowleri has yet to be connected with an adult medusa bearing

gonads. At its present stage it has eight tentacles, which admits it to the genus

Cunoctantha; but in the adult stage it may have more than eight tentacles, in which

case it would belong to the genus Cunina.

PEGANTHA sp.

There are two specimens which are not in good condition. They look like young

stages of a Pegantha, and are without gonads.

(a) Umbrella about 7 mm. in width and 5 mm. in height; 13 tentacles alternating

with 13 marginal lobes. About three sense-organs on each lobe.

(b) Eleven tentacles and eleven lobes. About five sense-organs on each lobe.

Occurrences: 200 to 0 fathoms. 36g (1).

350 to 0 fathoms. 36/ (1).

THE MEDUSA. 179

SOLMUNDELLA sp.

The collection contains two early stages, which are in rather bad condition.

Occurrences: 75 to 0 fathoms. 34 (1).

100 to 0 fathoms. 22a (1).

Order SCY PHOMEDUS &.

PERIPHYLLA sp.

Two quite early stages, the larger measuring about 7 mm. in diameter. The

specimens are not in good condition, but the margin of the umbrella is sufficiently

complete for the identification of the genus.

Occurrences: 350 to 0 fathoms. 36 / (1).

400 to 300 fathoms. 21% (1).

Distribution —Periphylla is one of the genera belonging to the group of deep-sea

medusz, and its species have a very wide geographical range. The Biscayan specimens

are probably early stages of Periphylla hyacinthina, Steenstrup, which occurs on the

European side of the Atlantic.

ATOLLA BAIRDII, Fewkes, 1886.

Atolla bairdii, Fewkes, 1886, p. 936, pls. 1-3; Vanhéffen, 1892, p. 16, Taf. 4; Vanhoffen, 1902, p. 9;

Maas, 1904, p. 49, pls. 4-5.

The collection contains one specimen, which has the margin of the umbrella in fairly

good condition, but the gonads, stomach, and mouth are mutilated.

The umbrella is about 40 mm. in diameter. Upon the central disc of the umbrella

there are radial furrows which are visible when the specimen is lifted out of formalin.

The presence of radial furrows is one of the characters for distinguishing Afolla verrillii

from Atolla bairdii; but as Maas has found indications of furrows on the central dise of

Atolla bairdii, 1 think that I shall not go far wrong in regarding the specimen as Atolla

bairdii. There are 21 tentacles and 21 sense-organs. The shape of the pedalia and the

marginal lobes resemble the figures by Maas of Afolla bairdii.

Occurrence: 1500 to 750 fathoms. 30a (1).

Distribution —Atolla bairdii occurs on the western side of the North Atlantic, off the

coast of North America; and on the eastern side from the Bay of Biscay nearly to the

Equator. It is a deep-sea medusa, and has been usually taken below 500 fathoms and

below the temperature of 50° F.

Prevacia? LEphyra stage.

Three specimens of very early Zphyra stages, which I am not able to identify with

certainty.

Occurrences: Surface. 21%, 23.e.

25 to 0 fathoms. 380m.

180 MR. E. T. BROWNE—BISCAYAN PLANKTON:

Meduse occurred in the following hauls, but the genera could not be recognized owing

to the bad condition of the specimens.

LEPTOMEDUSZ.

fathoms.

200-0 369 (1).

350-0 36/ (1).

TRACHOMEDUSE.

50-0 36 d (1).

75-0 35 a (1).

100-0 35 x (1), 366 (1).

200-0 36g (2).

250-0 36h (5), 367 (5).

300-0 36 k (3).

350-0 367 (1).

NARCOMEDUSA.

100-0 33 d (1).

250-0 36% (1).

500-250 29 a (1) (trawl).

1000-750 31d (1).

2000-1000 30e (1) (trawl).

EXPLANATION OF PLATE 18.

Reference letters.

B. Medusa-bud. Ot. Otoporpa.

Ec. Ectoderm. P. Peronium.

En, Endoderm. Sp. Stomach-pouch.

Ex, Ex-umbrella. Spe. Cavity of stomach-pouch.

Mes. Mesoglea. Sub. Sub-umbrella.

O. Opening into stomach-pouch where a T. Base of tentacle.

medusa-bud has been removed.

Cunoctantha fowleri, sp. n.

Fig. 1. Oral side of the medusa drawn to show the pouches of the stomach with medusa-buds in yarious

stages of development. Semi-diagrammatic. x 20.

Fig. 2. Transverse section of a pouch of the stomach (drawn with the aid of a camera lucida), showing

two very early medusa-beds. The bud B' is just beginning to develop, and bud B" is at a

little later stage. x 120. ,

Hace

! Ss GaiDp

é ANY” <Sitm, MO

a te,

Ne ,, -

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SSS STS

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GEIGER fees

ior

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CUNOCTANTHA FOWLERI.

Trans. Linn. Soc., Ser.2. Zoon.Vol.X.Pr.1s.

E.Wilson Lith, s Imp

THE MEDUS&. 181

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Cuun, C., 1894.— Celenterata,” in Bronn’s ‘ Thier-Reich.’

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(1886-1903).” Résult. Camp. Scient. Albert de Monaco, fase. 28, 71 pp., 6 pls.

Maas, O., 1905.—“ Die craspedoten Medusen der Siboga-Expedition.” Siboga-Expeditie, x. 84 pp..

14 Tafn.

Mayer, A. G., 1900.—“ Some Meduse from the Tortugas, Florida.’ Bull. Mus. Comp. Zool.

Harvard, vol. xxxvii. pp. 11-82, pls. 1-44.

Mayer, A. G., 1904.—“ Meduse of the Bahamas.” Mem. Nat. Sci. Mus. Brooklyn Instit. vol. 3.

pp. 1-83, 7 pls.

Merscunikorr, E., 1886.—“ Medusologische Mittheilungen.” Arbeit. Zool. Instit. Wien, Bd. vi.

pp. 237-266, Taf. 1, 2.

Vannirren, E., 1892.—Die Akalephen der Plankton-Expedition ‘ National’ Bd. ii. K.d. 30 pp., 4 Tafn.

Vanuorren, E., 1902.—“‘ Die craspedoten ‘Medusen der deutschen Tiefsee-Expedition ‘ Valdavia.’ ”

Wissen. Ergebnisse, Bd. iii. pp. 55-86, Taf, 9-12.

182 DR. G. H. FOWLER—BISCAYAN PLANKTON:

NOTE ON THE DISTRIBUTION OF THE MEDUSA,

By G. Herserr Fow ier, F.L.S.

ALL specimens of Medusee, however greatly damaged *, were as far as possible picked

out from the various hauls and submitted to Mr. Browne. |

sufficient regularity to allow of their being dealt with statistically ¢ in the manner

attempted for some other groups in these Reports.

RHOPALONEMA C@RULEUM, Haeckel.

t In hauls with open nets at

350

fathoms, this species occurred in

per cent. of the

hauls, with

haul, with

0:04

0:33

1:30

0:50

2:00

0-00

0:25

0°25

0:00

0:50

Three species occurred with

average specimens per hour haul.

It was not taken in any closing-net, and may fairly be set down as a purely |

epiplankton species, with a maximum distribution at about 50-100 fathoms. Nowhere

plentiful, it was least so at the surface, of all the five epiplankton zones investigated.

AGLANTHA ROSEA (Forbes).

In hauls with open nets at

font

fathoms, this species occurred in

Sao as ire 1S

per cent. of the

hauls, with

haul, with

0-9

0:0

0:8

0:0

0°25

0:0

average specimens per hour haul,

* Incidentally it is worth noting that of 27 specimens so damaged as to be generically unrecognizable, 19

(70 per cent.) occurred in the five serial hauls 36 g to 1—a fact to be considered by those who advocate “ the differential

method of serial tow-nets ” for the study of mesoplankton.

+ In the following tables the usual time-factor has been employed (p. 60, note); the 9 hauls with a net of

180 meshes per linear inch have been included, as having caught meduse, and averages have been struck over all

hauls at the depth mentioned, not merely over those in which the species occurred.

+ These tables are to be read as a sentence from left to right.

THE MEDUS. 183

It is obvious that of the five epiplankton zones studied, this species was most plentiful

in number and most frequently captured at 100 fathoms.

Unlike the previous species, it also occurred in eight closing-nets. This number is

not large, out of a total of 37 such nets, but sufficiently large to suggest that the species

was really alive at some considerable depth, and that the captures, at any rate in the

upper mesoplankton, were not merely of dead specimens sinking to the bottom ; in the

lower zones they may have been so, as this was the commonest epiplankton species.

The following table shows a sudden drop below 500-400 fathoms in the average

number of specimens captured per 100 fathoms traversed :—

150-50 3 7 1 1 7-00

200-100 g Bg 2 eee Omi

g 300-200 2 1 2 1 = 27 hose eee

2 500-400 eee 1 8 3) aoa ea

Be w0-500 2 1 & 1 2 a Seog ss

1000-750 £ 1 * 17 5 8 oo8 8%

1250-1000 = 1 1 3 013”

This drop may indicate approximately the break between living and dead specimens ;

and in this connection it is interesting to compare the observations on the same species

in the Feroe Channel (Proc. Zool. Soc. 1898, p. 1023). I have also added a similar

comparison of the distribution of Aglantha digitalis in the Feroe Channel with the six

specimens from the Bay of Biscay which Mr. Browne thinks may perhaps be referable

to this species (p. 176 above).

rosea, digitalis.

Locality. : | l yin |

Captures. Fathoms. Temp. ° F, Captures. Fathoms. Temp.° F. |

Highest .... 0 54 | Highest ....| 200-100 39-46 |

Feroe

Puannel--| Lowest’ ....| 100-0 48-54 || Lowest ....| 500-400 30-31 |

(| Highest .... 0 63 |

(, 500-400 49-50 | |

uny of | 750-500 46-49 | (| 750-500 | 4649 |

Biscay. \ | Four é | |

Eaeat 1000-750 | 40-46 All ..< | 1000-750 40-46

nN {1250-1000 38-40 \| 1500-750 S746 |

It may be only a coincidence that rosea failed below a temperature of 46°-48° in the

Feroe Channel, and that below 49°-50° the average specimens per 100 fathoms

* Actual numbers captured.

SECOND SERIES.—ZOOLOGY, VOL. xX. 31

184 DR. G. H. FOWLER—BISCAYAN PLANKTON:

traversed drop to about 0-1 in the Bay of Biscay. If so, it is all the more curious,

since digitalis failed at temperatures above 46° in the Feeroe Channel, and the supposed

digitalis above 46°-49° in the Bay of Biscay. While fully recognizing that these may

be only double coincidences, I incline to the idea that they really give us the approxi-

mate temperature-limits of these two species—the maximum for digitalis, a truly Arctic

form described from Greenland ; the minimum for vosea, a temperate and tropical form.

Unfortunately, owing to Haeckel having united them, it is practically impossible to be

certain to which of them the older records refer ; otherwise we should have a reliable

check on this question. But it is worth noting that in a collection of Medusz from

Norway and Spitzbergen, on which Mr. Browne reported for the Bergen Museum

(References, p. 151 above, Browne, 1903), Aglantha rosea extended from Southern

Norway up to just inside the Arctic Circle (Skjerstadfjord), while Aglantha digitalis

appeared only from the Lofoten Islands. This fits in well with the previous suggestion,

and points to the probability that 4. 7osea prefers warmer water than digitalis ; although

they may overlap at about their temperature-limits, the maximum of the one is probably

fairly close to the minimum of the other, and neither is very far from 47° F. (8°38 C.).

AGLAURA HEMISTOMA, Péron & Lesueur.

o Os Se 0°4

oO o n

z. E q Z

S .. 25 a. 50 mee Go

Sr 3) lem Ze

= & ° B= a

Pia) 50S ve aaee LGAie

a aw ae bo 3

5 e, cI oO as 2

= Ua iB 54.0 28 54

| oan]

| a -

=| = o 3

La 100 <& 27 16

Several of the epiplanktonic species treated earlier in these Reports have shown a

marked and puzzling predominance at 50 and 100 fathoms, but not 75; this, both in

frequency and numbers, exhibits a similar predominance at 25 and 75, but not at 50.

It was not taken in any closing-net, and was obviously purely epiplanktonic.

None of the above species occurred with such regularity at the surface as to enable

any deduction to be made with regard to a vertical oscillation.

Taking the species together, and including indeterminable specimens :—

a 0 40. ah

Se eee

= iy AS Sh fe} & 4:3 Sa

ee a3 Fairs ae

E@ 50. Br 184. 5 ees

n as +E ow

‘al EB 9 Ay we

s 75 NSc6 Sites 43 £5

a & o &

= 100 100 © 97

THE MEDUS#. 185

Both in actual numbers and in frequency of occurrence, the Medusze as a whole were

most plentiful at about 50-100 fathoms, scarcest at the surface.

ATOLLA BAIRDII, Fewkes.

Out of the sixteen captures recorded for this species, fourteen were in deep water with

open nets, and are therefore practically useless for the determination of either the depth

or of the temperature-limits. One was taken at the surface, apparently just in the cold-

water belt of the Eastern United States, one by the ‘ Princesse Alice’ in 1905 with the

Giesbrecht closing-net at about 928 fathoms, and somewhere about 428 F. The capture

in haul 30 @ shows a temperature between 37° and 46° F. (2°-7 to 7°'7 C.).

The following table exhibits the distribution of the captures, by hauls and depths.

The first three hauls were made with the closing “ mesoplankton trawl.”

186 DR. G. H. FOWLER—BISCAYAN PLANKTON:

Depth in

fathoms.

Haul.

argelis

autumnalis.

| Obelia lucifera.

achynema

eurygaster.

Colobonema

sericeum.

hopalonema

caeruleum.

Homaonema

platygonon.

glantha

rosea

hemistoma.

Cunoctantha

fowleri.

Pegantha sp.

glaura

Periphylla sp.

| M

| Tima sp.

| Tr

| R

| A

| Solmundella sp.

500—250 29 a

1500—750 30 a

2000—1000 30 e

| 2 ee | Aglantha sp.

| a | Atolla bairdii

cele | Ephyre.

| Hoe | Spp. indeterm

0 21e sored

—

tbo

)

[De Oo pe!

es)

co bo

25—0 26a

Pee

rar

Oo bo

50—0 Qlg

—

PRR oe

I oo

PHO:

75—0 BOF fee | ee fod eel cleo ee

a Ne

Co Ab

THE MEDUS.

LHomeeonema

Depth in

fathoms.

Haul.

eurygaster.

platygonon.

glantha

rosea

hemistoma,

Cunoctantha

autumnalis.

Colubonema

sericeum,

ceruleum,

fowleri.

Solmundella sp. |

Margelis

Obelia lucifera.

Trachynema

| Aglantha sp.

Aglaura

Pegantha sp.

Periphylla sp.

Spp. indeterm.

| Tima sp.

'| Rhopalonema —

cS)

= miro wrt | 4

war ew Psy i

100—0 21h

iy)

tobmor it

RONDE RRR IR HY!

; por:

2]...

150—0 36,f el aeled hs... | 5. |

150—50 2p eee nee |. 5, |<. |

150—100 21 n a |

200—0 Qla |

Ne pr?

200—100 21b

250—0 36h Palen. | 1 |

iach:

250-150 | 350

ee)

83 .

300—0 36k Roleeitee | ce |c: |. | ere a ft...) 8a

300—200 Qe BeWee Reeth. |< | |, al | |

350—0 361 Rivets |..|.. | | eer bh. fa lad.) 24

400—300 21k ate | eet. |. |

500—400 21m

750—500 225 Boe obhats fae | «0 <4 pea ain i]

| |

1000—750 23a Sere. |. | os Peeeeeamenen ae fers

1250—1000 4a Peeetlhie | as {cea ene

2000—1500 25e

| |

SECOND SERIES.—ZOOLOGY, VOU. X. 32

| |

1500—1250 Qf |

(0 6)

2 —eEeE—

(18a a

BISCAY AN PUAN ON.

Part X.—THE FISHES.

By E. W. UL. Hour and L. W. Byrne.

(Communicated by Dr. G. Hurserr Fow er, F.L.S.)

Read 6th December, 1906.

TABLE OF CONTENTS.

Page

Mem lire trode Lome speertereraie voter tc: flats y's + 0) 6) vw) cl ovo censeaqeye Seen eeAead Rene eee a) sce 189

TEwihe VerticalaDistrbution ot Oya and Larvee ....540seeeeeemoese ss... 190

HEE TerS peciessorsMishycaptoreds se... w.0s.<-s:</c soccer metaeeter ee aie «cio 192

SToMIATID&. SLOMUASHOOG,, ISSO: © ...\:/. oka Ee ees ane « 193

An CUPODELECUSISD Ds. )ist tee atte ater) 193

Wauroncusiboreatis, Nilssonlepenasee meen. ae « 194

Gonostoma bathyphilum (Vaillant) ................ 194

Gonostoma microdon, Gunther sceees sane =. - @ - 194

SSRTSSCOPO LATVA. «x's: cia cote eterna ste eves - 195

AnevittuLipz. Conger vulgaris, Cuvier; Larva .................. 197

ScopELip®. Neopelus ajinesqui, Coccoys sa tusetsy eerste is +) < 197

Scopelus glacialis, Reinhardt <-veecisitae ede > «+ + 197

Scopelid Larva; “RL” tyscpacsewmnmectociaceeics« «/<="s 198

, a RO hacer reins» 198

” 9) PRB ieee Moers 102 2s 198

‘oPeriscope” Larva. .s «ae as cesta serie ats aie sis 199

SynenaraipH. Nerophis equoreus, var. evilis, Holt & Byrne ........ 200

CaRAaNGID&. Caranaltrachurus, li. sapere einen es ase 00

IkCuRDARSEDISsee ce long=anal” Darvas. .mcirda aetmereernerrraicietalsrs/s 2 6 200

Se Ncorpsepilorm:” Tiarvay peter sateen tereiohe soles ct.e! «/ 201

Triploid,” Larva. «a gretepsreccsecetemmeeperacta’ o+.c.00 5 201

I. InrRoDUCTION.

THERE are probably few classes whose representatives (and especially larvae and ova)

suffer more from the ordinary processes of capture in a tow-net, and from preservation in

company with numerous other animals, than fishes. It is consequently not in the least

surprising that the results of our examination are very meagre in comparison with the

amount of material submitted to us. This is, we think, inevitable, unless an expedition

is so well provided with observers as to make it possible immediately to pick out and

preserve fish larvee and ova as soon as the contents of a tow-net are brought on board.

So far as the condition of our specimens bears any relation to the preserving media

used, those which have been preserved in a weak solution of formalin appear to be most

satisfactory; a good many tubes, however, contain larve blackened and _ shrivelled

beyond recognition, probably as a result of over-fixing in some solution containing osmic

acid or corrosive sublimate.

A practical observation that seems called for by the nature of the results attained is

SECOND SERIES.—ZOOLOGY, VOL, X. 33

190 MESSRS. E. W. L. HOLT AND L. W. BYRNE—BISCAYAN PLANKTON:

that, to determine with any accuracy the vertical range of the ova and larve of fishes

which live at or near the surface over deep soundings, hauls must be made with closing

tow-nets through short distances in the surface-waters, particularly, we think, between

100 and 25 fathoms. Dr. Fowler’s results seem to show that fish-larve are uncommon

at the surface, and even between 25 fathoms and the surface; but between what depths

in the succeeding 75 fathoms they are found, and whether there is any difference in

vertical habitat between the larve of different species, remains yet to be investigated.

Jn the succeeding pages we shall first discuss the vertical distribution of the ova and

larvee recorded as a whole, secondly give a list in systematic order of the species of fish

met with, together with the vertical distribution of fishes with adult characters, and lists

under each species of recorded occurrences during the cruise.

II. Tur VERTICAL DISTRIBUTION OF OVA AND LARV2.

Though Dr. Fowler’s nets naturally took only fishes of small size, it seems advisable

to treat the ova and larvie at first separately from those forms which, though small, had

attained the adult conformation, and subsequently to treat the question of the vertical

distribution of the adults when dealing with the individual species; in the case, how-

ever, of ova and larvee, the number of more or less spherical objects submitted to us as

possibly fish-ova, whose exact nature it has been impossible to determine, and the

numerous larvee, whose parentage and appearance in life cannot even be conjectured,

make it impossible to treat the question of distribution otherwise than in the most

general terms.

The following table shows the number and percentage of hauls in which “ova

larvee occurred :—

”

and

Depth of hauls, | No. at each | No. containing | Ape No. containing eee

| |

| — = aa = 4 _ = eee

| 0) 25 | if 28 2 12

25 | 12 | 3 | 25 8 66

| 50 | 13 | 4 30 12 92

| 75 | ae 2 18 Ht 100

| 100 22 PS) 36 17 72

| 150 | 1 ae |

|. 200 | 2 1

250 2 2 2

| 300 | 1 1 ee 1

| 390 | 1 . 1

* In one of these hauls the catch was a Gonostoma microdon of 18 mm., perhaps hardly a larva,

THE FISHES. 19]

The ‘ Research’ made in all 128 tow-net hauls, of which 90 were either fished at, or

were open up to, the surface, while 37 were stopped by the closing of the net at depths

varying from 50 to 1500 fath. The tow-net hauls which closed below the surface include

18 which came within 300 fath. of the surface, viz. 3 closed at 300, 3 at 200, 3 at 150,

8 at 100, and 1 at 50 fath.; but none of these, nor any of the 19 hauls closed at greater

depths, yielded evidence of the presence of larvee.

Even ova taken in deep water often suffer from capture, as it is quite common to find

in the ‘ Helga’ collections tough spinous shells of the character associated by Raffaele

with Macrurus, quite devoid of contents; and it is reasonable to suppose that broken

shells of a more delicate character might easily escape observation. Very young larve

are much more delicate than ova, and even those of littoral species are usually mangled

beyond recognition in tow-net gatherings from shallow water. It may therefore be

said, without the least disrespect to the skill and care employed in the sorting of

‘the ‘Research’ material, that the apparent absence of larve from the sortings of the

deeper gatherings does not absolutely prove that no young larvee came in the way of

the nets.

The table given above (so far as any conclusion can be drawn from the few taken)

points to ova being fairly evenly distributed right up to the surface. In the case of

larvie it would seem that they were generally distributed between 100 and 25 fath.,

somewhat scarcer in the upper 25 fath., and very scarce at the actual surface. The

paucity of hauls commencing at more than 100 fath. renders it impossible to say at what

depth below the surface the greatest comparative density of larvae commenced. The

genus Scopelus we suppose to be represeuted in 17 gatherings, and in 16 we have noted

the occurrence of Maurolicus or a very similar form (probably in all cases VW. borealis) ;

but we think that many of the young or damaged larvee to which we have not ventured

to give even a queried name may also be Maurolicus.

Turning to the question of diurnal oscillation of larvee, the results seem to be negative.

It is true that the only captures made by purely surfage hauls took place at night, but

9 out of 11 night hauls were blank. In the hauls made from 25 to 0 fath. larvee

were taken except at midnight, 2 am. 6 aM. and 8 am. At 50 to 0 fath. every

haul, except one of two made at 4 p.m., produced larvee, and larvee were taken at

75 to O fath. throughout the 24 hours. At 100 to 0 fath. blank hauls were made

at 2a.M., 4A.M., 7 A.M., 11 a.m,12 noon, and 6P.m.; but the success and failure of

hauls in the hours of daylight and darkness is not in such contrast as to lead to any

certain conclusion.

Taking all the superficial hauls (100-0 to 0-0 fath.) together, it is apparent that

relatively to the total numbers under each condition blank hauls were more frequent by

day than by night; and if we interpret the somewhat sporadic catches in the hauls of

100-0 fath. to mean that the larvee were mostly in the upper 75 fath., there is some

approach to evidence of a descent during the hours of daylight.

The fact is that the grouping of the larvee as a whole, due to our failure to recog-

nize the parentage of most of them, obscures the result; and we cannot treat them

33*

192 MESSRS. BE. W. L. HOLT AND L. W. BYRNE-—BISCAYAN PLANKTON:

separately, because many of the smaller and of the mutilated specimens may probably

belong to some of the species which we have recognized.

The known larvee of many 'Teleosteans evince no repugnance to the surface in calm

weather. Other known larvee seem to avoid it, and the probability is that the diurnal

oscillation of Biscayan fishes represented by larve at the time of observation is not

susceptible of generalization.

III. THe Srectes oF FISH CAPTURED.

The fishes and fish-larvee taken by the ‘ Research,’ so far as they are recognizable, are

enumerated below; larval forms are inserted either under the genera or families to

which we regard them as referable, or under names which are intended to serve no

purpose beyond facilitating reference.

In the following pages are notes of the occurrences of the various species and larve,

with a few remarks on their distribution and morphology where these appear to be

called for.

So far as the larvee are concerned, we have not attempted to describe with any

completeness either forms of which our material is deficient or those better known

to us from other collections which are not as yet fully worked out. In the case

of the “ Prescope” larva, which we have never met with in any gathering other

than those made by the ‘ Research,’ we have given a description of the stages

known to us.

Very few of the fishes with adult characters, perhaps none, are sexually mature, but

they have reached the phase of structural development which, in the case of the few

littoral species of which the life-cycle is fairly well known, is marked by the assumption

of habits approaching those of fully developed individuals. It must, however, be

remembered that among littoral fishes even an approximately complete knowledge of

life-history has been attained only in the case of some of the commoner species which

take to the bottom when adult, and by no means extends to consistently pelagic

forms. Probably all the ‘ Research’ fishes (except, of course, the Conger) are pelagic

throughout life, and there is no obvious reason why their vertical distribution should

vary with age, except it be found in the greater power of the perfect individuals

to respond to stimuli inducing vertical movement or in bathymetric necessities of

reproduction.

So far as we are aware, Dr. Fowler’s work in the ‘ Research’ comprises the first exact

records of the distances from the surface at which certain oceanic fishes have been

taken.

THE FISHES. 1938

STOMIATIDS®.

STOMIATIN&.

STOMIAS BOA, Risso.

Young specimens were taken in the following hauls :—

23a. One, 47 mm. 337. One of 46 mm.

25k. Two of about 45 mm. 33g. One of 57 mm.

26f. One of about 50 mm. 34d. One of 60 mm.

27a. One of about 50 mm. 360. One of 52 mm.

31 6.. Six, 58-47 mm. 36k. One of about 50 mm.

320. One of 36 mm. 36/7. One of 51 mm.

382 p. One of 46 mm.

A common species of the North Atlantic, whose occurrence in this area might be

expected. The specimens taken range from 36 to 60 mm. in total length. One of the

smallest (47 mm.) and one of 50 mm. occurred in nets which closed respectively at

750 and 200 fath. from the surface. The remainder were caught in hauls carried to the

surface from depths of 350 fath. and less (except one taken hetween 1250 and 0 fath.).

The largest catch, 6 specimens of 47 to 56 mm., was made between 50 and 0 fath.

It would therefore appear that young examples of this species have a fairly wide

vertical range.

The disclosed distribution of young S. doa demands some attention, for, although it is

obviously unsafe to draw any positive conclusions from a species present in only 10 per

cent. of the hauls made, the record is at least unproductive of evidence against diurnal

oscillation in the young of this species.

Stomias boa was captured as follows :—

Hauls at 4.0 a.m. to 7.0 P.M. 7.0 p.m. to 4.0 a.m.

0) in O out of 13 in O out of 12

25 EP) 0 oP) 6 » 1 »” 6

50 oP) 0 9 8 ; »? 3 2) 4

75 sy ee oe ©

100 oy 0) ro alias Le i oD

During daylight it was captured also at unknown horizons by open serial nets between

300 and 0, 350 and 0, 1250 and 0 fath.; it was also taken in closing-nets between 300

and 200 and between 1000 and 750 fathoms.

STERNOPTYCHINE.

ARGYROPELECUS Spp.

A single specimen, apparently referable to A. olfersi, 45 mm. in length, was taken

at station 32 7 between 100-0 fathoms at 11 P.M.

Argyropelecus larvee similar to that already figured by us (Holt & Byrne, Ann. &

Mag. Nat. Hist. ser. 7, xiv. (1904) p. 38) occurred in the following hauls :—

36g. Five, 7°5 to 6°5 mm. | 86h. One, 7°5 mm.

194 MESSRS. E. W. L. HOLT AND L. W. BYRNE—BISCAYAN PLANKTON :

Smaller larvee, under 3 mm. long, possibly referable to this genus, were taken in 7

other hauls, in none of which the net descended below 100 fathoms.

The area fished by the ‘ Research’ is well within the known horizontal range of this

genus, whose members are probably denizens of the surface-waters of the deep sea

at all stages.

GONOSTOMATIN ©.

MaAvROLICUS BOREALIS, Nilsson. (Fig. 1.)

Fig. 1.

Miiji

Maurolicus borealis larva 10 mm. long. Diagrammatic camera Jucida sketch, x 10°5 ca.

Larvee referred by us to this species occurred as follows :—

25k. Four, 45-7 mm. | 32”. Three, 8-10 mm.

807. Nine, 6-10 min. | 366. ‘Two, 12-14 mm.

380m. Sixteen, 3°5-6°5 mm. 36c¢c. Four, 3-9 mm.

It is remarkable that all these captures were made between 11.0 p.m. and 2.0 a.m.

Other Jarvee, which may belong to this genus (and, presumably, species), but cannot,

owing to their condition, be referred to it with reasonable certainty, were taken in ten

other hauls between 100 to 25 fathoms and the surface, of which three were daylight

hauls. j

The area fished is well within the known horizontal range of the species. Of its

vertical range we have not very much definite information, but suspect that such

specimens as we have obtained from comparatively shallow water (about 110-180

fathoms) off the Irish coast were taken nearer to the bottom than to the surface.

GONOSTOMA BATHYPHILUM (Vaillant).

Twice captured :—

30a, One of 85 mm. (without caudal). | 30%. One of 110 mm. (without caudal).

This species is already known from both north and south of the area fished by the

‘Research.’ We get it occasionally in Irish collections, but not under circumstances |

which indicate a much nearer approach to the surface than that shown above, while

earlier records all deal with captures made in nets sunk to over 1000 fathoms.

GONOSTOMA MICRODON, Giinther.

Once recognized in haul :

36 h. 250-0 faths., 10 a.m. One of about 18 mm.

THE FISHES. 195

In the Ivish collections this fish is common in nets lowered to considerable depths.

We know of no record which proves its occurrence, in Atlantic or Pacific, at much less

than 265 fathoms.

Fish-remains from the following hauls, 329, 32 0, 34,f, 35 c, may possibly be referable

to this species. If, in fact, so referable they considerably extend its proved upward

vertical range.

The following larva appears to us to be clearly referable to Boulenger’s subfamily

Gonostomatine.

“Prescope” Larva. (Figs. 2 & 3.)

** Prescope ” larva 15 mm. long, x 10 ca.

Fig. 3.

‘* Praescope ” larva 9 mm. long, x 17°5 ea.

Specimens of this form occurred in the following hauls :—

246. One of 13 mm. | 35d. One of 9 mm.

24e. Two of 15 mm.

Small elongate larvee, of which some may probably be identified with this form, occurred

in one of the above hauls and five others, all fished from between 100 or 50 fathoms and

the surface at various hours of the day and night. None of these latter larvae, however,

have any characters of a nature sufficiently definite to permit of their reasonably certain

association with this form.

The evidence of vertical range is too slight to permit of any conclusions being drawn,

but it is worth noting that the “Priescope” larva has not been found in any haul

commencing nearer the surface than 50 fathoms and only certainly identified in hauls

commencing at 100 fathoms. This form has not been recognized by us inany of the large

collections made by the ‘Helga’ in deep water off the west and south-west coasts of

Ireland, and we accordingly append a somewhat fuller description than in the case of

larvee of which we may reasonably anticipate a fuller material in the near future.

196 MESSRS. E. W. L. HOLT AND L. W. BYRNE—BISCAYAN PLANKTON:

The most advanced specimens measure 15 mm. and have the form shown in fig. 2.

The head is a little longer than the abdomen, and head and abdomen together com-

prise a little less than half of the total length without the caudal fin. The eye is

relatively large, but not remarkably so fora larva. It is somewhat forwardly directed,

as in many deep-sea larvee and, to a less extent, in the adults of deep-sea fishes. The

snout is long and sharply pointed in lateral view. Its sides are subvertical and sharply

defined from the flattened upper surface. The angle of the jaw reaches or passes the

vertical from the hind edge of the eye. The teeth appear to be rather small and, as

usual in larvee, set at considerable intervals. The pectoral fins are large and set low

down on the body; they would extend if perfect at least to the anus. The ventrals are

small and situated a little way in front of the anus. The dorsal shows from 10 to 12,

and the anal 13 to 17 rays, but when the larvee are examined from the ventral aspect it

appears probable that in the adult condition the anal is continued further back than

appears in the figure. The dorsal commences a little behind the origin of the anal.

There is a low fold of embryonic marginal fin in front of the dorsal, commencing at

some distance behind the head, and a similar ventral fold between the bases of the

pectorals and ventrals. The caudal is of moderate length and rather deeply forked.

An adipose fin, if present in the adult, would probably be conspicuously indicated by

embryonic rays at this stage of development, but cannot be detected in any of the

specimens. There are about 15 abdominal and about 21 caudal myomeres, but the exact

count is uncertain.

On the lower edge of each gill-cover, or on the isthmus internal to it, is a large photo-

phore, consisting of a base of black matter and a rounded opaque white apex. “ Four

similar bodies, set in two closely apposed pairs, occur on the abdomen immediately in

front of the ventral fins. The larvee are devoid of dark pigment, other than that of the

eyes, except for a black spot in front of the caudal base.

A specimen of 18 mm. shows 12 dorsal and 15 anal rays, and has the snout somewhat

arcuate in dorsal profile. This last feature appears to connect the stage of fig. 2 with

the larva depicted in fig. 3, which measures 9 mm. So far as we can count, the

myomeres are of the same number as in the larger specimens. The position of the

alimentary canal, which is slung obliquely from the trunk in the ventral marginal fin-

fold, may be due in some measure to post-mortem distortion. About midway in the

caudal region the trunk shows a ventral opaque excrescence, of which the nature is not

apparent. It does not look like any phase in the development of an anal fin and may

probably be due to injury.

Though the collection comprises a number of small elongate larvee of which some may

probably be specifically identical with “ Preescope,” none have any characters of a nature

sufficiently definite to permit of their reasonably certain association with this form.

A process of elimination causes us to regard this larva as that of a member of the

Gonostomatine. The suggestion of a probable parent is not easy: a comparison with the

adults of known genera and species points to Gonostoma itself; and, although it would

prima facie appear improbable that a Gonostoma would attain its adult characters

through an early stage resembling the “ Preescope ” larva, we cannot premise that fishes

THE FISHES. 197

whose phylogeny is at best imperfectly known may not in their ontogeny pass through

phases considerably different from the adult condition. It may be remarked that (to

judge from figures) Photichthys (including Goode and Bean’s Yarrella) has a great look

of the “ Praescope” larva, which may be referable to some undiscovered member of that

genus. So far as Gonostoma is concerned, two species, G. microdon and G.. bathyphilum,

occur in the areas worked by the ‘ Research’ and the‘ Helga,’ the first being exceedingly

common, the second apparently scarce: G. microdon seems an almost impossible parent

for this larva from considerations of size, quite apart from anything else; G. bathyphilum

may be responsible, but if so the absence of this larva from the Irish collections is

somewhat remarkable.

ANGUILLID 2A.

CoNGER VULGARIS, Cuvier.

A leptocephalus larva of this species, 182 mm. long, was taken at Station 30 m between

25 fathoms and the surface at about 11 p.m. This capture over soundings of more

than 2000 fathoms seems to indicate a considerable horizontal wandering from the

normal haunts of the adult (which is not known, we believe, to descend to much

beyond 400 fathoms), but is in consonance with other records of its leptocephalus stage

(ef. Schmidt, Cons. Intern. Exp. Mer, Rapp. et Proc. Verb. v. p. 137 [1906)).

ScoPELIDA.

SCOPELUS RAFINESQUI, Cocco.

A single specimen, about 40 mm. long, was taken at Station 86 d between 50 fathoms

and the surface at about 1 a.m.

This capture is in consonance with what we already know of the vertical and horizontal

distribution of the species.

ScoPELUS GLACIALIS, Reinhardt.

29a. One, about 19 mm. | 34a. One, about 20 mm.

316. Three, 46 mm., 29 mm.,and2l mm. | 34c. One, about 21 mm.

32p. One, about 13 mm. | 34d. One, about 20 mm.

33d. One, about 18 mm. | 35c. One, about 16 mm.

33f. One, about 15 mm.

These records help to extend the known horizontal range of this species in a south-

ward direction, and we can now trace a continuous distribution on the eastern side of

the Atlantic from Greenland wid the coast of Norway, the Fiiroe Channel, and the west

coast of Ireland to the North Biscayan region, while Dr. Wolfenden in the ‘ Silver Belle’

took it in Feb. 1906 in the Mediterranean off Marbella, about 20 miles N.E. of Gibraltar,

Fowler’s conclusions (P. Z. 8. 1898, pp. 559-560), based on a summary of the then

existing records, as to the thermal limitations of its range, would appear to require

some modification, since the largest ‘ Research’ specimen was taken at not more than

5) fathoms from the surface, and we understand that the net used in haul 294

(‘‘mesoplankton trawl”) might have admitted a small fish during its ascent to the

SECOND SERIES.—ZOOLOGY, VOL. X. 34

198 MESSRS. E. W. L. HOLT AND L. W. BYRNE—BISCAYAN PLANKTON :

surface. The American and Irish material, taken in open nets, afford no certain

indication of vertical position of capture, and may have been taken in either warm or

cold water. Attention may be drawn to the fact that all the specimens except that in

haul 29 a, between 500 and 250 fathoms, were taken by night, and our remarks on the

possible vertical oscillation of Stomias boa apply, though in less degree, to this species.

The following larval forms seem undoubtedly referable to this family and to the

genus Scopelus.

1. Scopetip Larva “ R1.”

A larva closely resembling that of S. glacialis (see Holt, P. Z.S. 1898, p. 550), with

which it is not improbably identical, although it seems to be rather smaller at

corresponding stages of development. It was taken in the following haul :—

32g. One of 6 mm.

Our material does not permit of a detailed description of any practical utility being

given.

2. Scoprtip Larva “R2.” (Fig. 4.)

Scopelid larva “R2” 8mm. long. Diagrammatic camera lucida sketch, x 9 ca.

These larvae were of somewhat frequent occurrence, and were recognized in more or

less damaged condition in the following hauls :—

30f. Four, 65-8 mm.

30 1. Five, 6°5-8°5 mm.

816. Four, 4°5-8°5 mm.

320. Five, 4—8 mm.

33 f. One, 6°5 mm.

865%. One, remains ca. 10 mm.

They closely resemble the larvee of S. glacialis, but are smaller and deeper in the

body, with a longer and more conical snout. Our diagram, taken from a specimen 8 mm.

long, may be compared with the larva of S. glacialis figured by Holt (P. Z. S. 1898,

p- 550) at the same length, and should suffice to show these differences.

3. ScopELip Larva “ B3.”

A larva which is larger than that of S. glacialis at corresponding stages, and has a

more elevated head and more abrupt profile, occurred in more or less damaged condition

in hauls:

301. One, with a head 2:25 mm. long. | 32n. One, 9 mm. Jong.

* There seems some doubt as to this record, as the label reads 36 6(?).

THE FISHES. 199

Their condition does not permit of a figure or detailed description being given, hut

they may conceivably be referable to Scopelus rafinesqui *.

‘“‘ PERISCOPE” Larva. (Fig. 5.)

*« Periscope ” larva 12 mm. in length, with view of head seen from above, and views from above and the

side of head of a smaller example 9 mm. long. Diagrammatic camera lucida sketch, x 9 ca.

This larva occurred as follows :—

25k. One, 6°5 mm. 32m. One, 8°5 mm.

30h. One, 5 mm. 320. One, 4:5 mm.

30 2. Two, 9 and 12 mm. 33c. One, 5 mm.

314. One, 7 mm. 35 6. One, 4 mm.

Other specimens, possibly referable to the same form, were present in two other

hauls.

It is a larva of the same type as that described by Lo Bianco (Mitth. Zool. Stat.

Neap. xvi. p. 109 [1903]), and a comparison with Holt’s figures (loc. cit.) of Scopelus

glacialis and the larva termed by us “R2” suggests that it certainly belongs to

the family Scopelidz, and not improbably to some species of Scopelus.

Our smaller material shows no diagnostic characters beyond the form of the head and

eyes, and is not in good condition.

Our diagrams of a specimen 12 mm. long and of the head of a smaller specimen of

9 mm. sufficiently show its characteristics at these sizes. The pedunculate character of

the eyes in the younger examples has probably no exact value in classification, as we

meet with exactly the same character in another larva (not taken by the ‘ Research’), in

which the abdomen extends almost to the posterior extremity.

* S. punctatus, being very abundant at times off the south-west of Ireland, may not improbably be the

parent of one of the species of larvie.

34*

200 MESSRS. E. W. L. HOLT AND L. W. BYRNE—BISCAYAN PLANKTON:

SYNGNATHIDA.

NEROPHIS ZQUOREUS, var. EXILIS, Holt & Byrne.

Occurred as follows :—

21g. One, 12 mm. | 30 7, One small and part of brood-matrix.

212. One, 13 mm. | 816. Four, 100-108 mm.; four, 7-17 mm.

247. One, 8 mm. | 33a. One, 21 mm.

25e. One, 8 mm. | 335. One, 11 mm.

25k. One, 72 mm. 34a. One, 90 mm.; fifteen, 8-18 mm.

306. Five, 9-15 mm. | 349. Two, 8 and 1] mm.

30 f. One, 97 mm. | 35 f. One, 7 mm.

30g. One small. | 366. One, 15 mm.

Here, as on the west coast of Ireland, common at or near the surface at all stages

(see Holt & Byrne, Fish. Ireland, Sci. Inv. 1905, ii.). We have little doubt that

the specimens taken by the ‘Caudan’ further south in the Bay, and recorded as

Syngnathus, are also referable to this form (Koehler, ‘Campagne de Caudan,’ 1896).

We have no evidence of its occurrence, either at the bottom or as a pelagic organism,

below 100 fathoms.

CARANGIDA.

CaRANX TRACHURUS, L.

Once met with:

34d. One of 80 mm.

This capture rather suggests that the net encountered a straggler from the protection

of a Rhizostoma or some other large Medusa, which may have drifted seawards from the

place at which it collected its clientéle, but little is really known of the movements

of either the ccelenterate host or the parents of its fish protégés. Scad appear near

the coast, in varying number according to the year, in summer and autumn, and

their presence in coastal waters may be occasionally demonstrated in winter by the

examination of stomachs of larger fish.

INCERT#£ SEDIS.

“ LonG-ANAL ” Larva.

This larva was taken in the following hauls :—

32p. One of 27 mm. 35. One of 14mm.

but is chiefly known to us from other collections. Fragmentary remains in haul 327

may also be referable to it. It is an elongate form characterized by a long pointed snout,

very short abdomen, and by the very early development of an anal fin immediately in

front of the caudal. ‘The sides of the abdomen are decorated by a series of large black

patches separated by narrow vertical unpigmented interspaces. A similar interspace

separates the black patches of each side. Towards the caudal extremity are a number

of small patches of internal pigment above and below the vertebral column.

THE FISHES. 201

This larva may probably be related to the Stomiatide, but it reaches a comparatively

large size without approaching the characters of any adult fish known to us. It has a

superficial resemblance to Paralepis coregonoides, but the abdomen is no longer than

the head, which is sufficient to eliminate the last-named species and its allies from the

list of possible parents.

“ SCORPHNIFORM ” Larva.

In the following hauls :-—

26c. One of 4mm, | 34c. One of 3°5 mm., one of 6°3 mm.

there occurred a “ Scorpzeniform ” larva which, at a length of 6:3 mm. (without caudal

fin), is a massive little fish having the general conformation of an adult Scorpena; but

as the only specimen of this size is in very bad condition, its true relationships are

matter of conjecture. It is certainly not §. dactyloptera.

Larvee of about 3°5 and 4mm., which we think belong to the same form, have the

body rather elevated, and adorned, after preservation in formalin, with rusty-brown

pigment along the divisions of the myomeres, except at the anterior and _ posterior

extremities.

TRIGLOID”’ LARVA.

We have listed as “Trigloid” a much-macerated larva some 4°5 mm. long from

haul 36d, 50-0 fathoms, about 1 a.m., which may, when perfect, have had characters

similar to those of a larval 7rigla.

NOTE TO THE FOREGOING REPORT.

By G. Hersert Fow.er, 7.Z.S8.

As Messrs. Holt and Byrne point out, the numbers of observed larvee which they were

able to furnish are not necessarily to be regarded as absolutely accurate; for these

objects are so delicate that further specimens may have been reduced to mere un-

recognizable fragments. Exactly the same reservation has, of course, to be made in all

those cases which I have endeavoured to treat statistically in former reports. They do

not profess to give an absolute, but a comparative, result; a comparison of haul with

haul, or of depth with depth, during the particular period of that cruise, is feasible,

because there is no reason to suppose that the destruction of specimens was pro-

portionately greater at one particular depth than at any other (except in the case of the

deep serial hauls, which have always been kept in a different category).

While, then, no single species was sufficiently plentiful or occurred with sufficient

regularity to allow of statistical treatment, there seems to be no reason why the pelagic

fish-larvze as a whole should not be so handled. There were about 230 of these.

202 DR. G. H. FOWLER—BISCAYAN PLANKTON:

The following table, for example, seems to show a concentration of the larve below

the surface, but short of 100 fathoms, whether considered from their number of

occurrences * or from the average specimens per hour haul f.

A ip =) 072 ' Be

se | P 2 gs

= . :

as ae a ors

Bae 50 Ze \ 56 nS

=| oz oe

Zee 75 tS gas oT

aS 20 3 ee

al WO) 729 = NG 4 oe

Further, a comparison of the hauls made in the dark hours with those made in

daylight seems to point to a slight upward movement of the larve at night; the

concentration of specimens rising from 75 fathoms to 25-50 fathoms. How far this

may be due to larve rising from the mesoplankton below 100 fathoms it is impossible

to say, but it seems obvious that there was a great concentration of fish-larvee at 25-50

fathoms during the dark hours.

| |

4.0 a.m. to 7.0 p.m. | 7.0 p.m. to 4.0 a.m. |

Depth in

aoe. Number of Average Number of BN ere

specimens specimens

hauls. hauls.

per hour. per hour.

Uperaere 9 0-0 7 05

DIS one 6 2°8 6 65

OMe 6 « 8 2°6 5 10-6

(ORs aese 3 36 8 4:2

WO: co oan 13 2-0 9 26

The following table exhibits the distribution of the captures by hauls and depths

The first three hauls were made with the closing ‘ mesoplankton

(L= larve).

trawl.”

* Compare p. 190, above.

+ In these tables the actual numbers have been treated as in previous papers of the series, and hauls with the

net of 180 meshes per inch omitted.

203

THE FISHES.

WAIL]

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«, doost19g ,,

“EU VALET |

‘SY BAley |

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$n9270.1nD AT

snoajodouhbiy | a

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Hq Wo eAeoeeo AAAARARARAAHARHA AA

: 4 ob pb SOEs Sea aerpaaes :

= . re RE ae rc 1 ;

aoe ah Pe ee ee

So ad ayer ene: Je Wig es OL eS Gane ae ie eee

Sis Sg Deine Gee Sian es AA ;

ee eer eee ee a bs Bie ents

2d ce Sie gah ae mec ftdidisa :

Be ae tte STEGER TSR Al See ee ae Bernd

pats ae meh ah ais wees ie Ph OS aes

pce} tas ogo tebe Use BAR. SoMa Sora es Ree nae ol

car eee og nF sree gin wie ck tne emer aeae aa vey

re wae aS OR > fae eee ee

Sake igh a: FSi ius teat pas Camere ee te feiss wena

Beare 3 UE eds Se ees GR aie eet amare

ree hae IF Site Reeceele cae soit ats ghar oat iat

204 DR. G. H. FOWLER—BISCAYAN PLANKTON.

Depth in

fathoms. Haul.

borealis.

onostoma

bathyphilum.

microdon.

“ Preescope”

larva.

onostoma

Scopelus

| Argyropelecus.

Maurolicus

glacialis.

| Larva “R 2.”

| Larve.

| Stomias boa.

“ ”

| “ Long-anal

| Ova.

100—0 21h

Che || su!

Oe)

tee feeder thes

Bini Sain RISSISiSiGistetet ast

150—0 36f

150—50 21 p

150—100 21n Pe |

200—0 21a | | |

200—100 21b

250—0 36h

250—150 550

300—0 36h oO il,

800—200 Qe

Kes

“h

350—0 361 ate a

400—300 Qk

600—400 21m

750—500 226

1000—750 23.4 Je leap

1250—1000 24a

1500—1250 257

2000—1500 250

Nerophis equoreus,

var. exilis.

Caranx

ndetermined

trachurus.

larve.

“ Periscope ”

larva.

| Larva “R 3.”

| U

BISCAY AN PLANKTON.

mat Aso

SS joo © ir ef

Parr XI.—DECAPODA. jag 2 eae AZ

wi LIBRARYisg

By STanuey W. Kemp, B.A. o zew /

(Communicated by Dr. G. Hersert Fowter, F.L.S.)

(Plates 14 & 15.)

Read 7th March, 1907.

So will be readily understood, the large majority of the Decapoda collected by Dr. Fowler

in the Bay of Biscay are larval forms.

Tow-nets, unless of exceptional size, are but ill adapted for the capture of free-

swimming Macrura, many of which are powerful swimmers and easily avoid capture

in small nets. Nevertheless, five species are represented by specimens which have

attained adult characters; they are—Amalopeneus elegans, Smith, Sergestes arcticus,

Ky., Acanthephyra purpurea, A. M.-Edw., Acanthephyra (Systellaspis) debilis,A. M.-Edw.,

and Hymenodora glacialis, Buchholz. The last named is represented only by macerated

fragments, and its identification therefore cannot be regarded as absolutely satisfactory.

So far as is at present known, only a small percentage of Macrura are pelagic, so that

the five species mentioned abcve probably represent about one-half of the free-swimming

forms which might occur in the district under observation.

The chief interest of the collection centres in the fine series of larval Acanthephyra

purpurea. The later stages in the development of this form have been determined by

Coutiére, and the material before me enables me to substantiate his suggestion that the

species leaves the egg in the form of a zowa. A comparison of the development of

this species with that of 4. debilis renders this feature noteworthy enough: A. debilis

has much larger eggs than A. purpurea, and Coutiére states that the young leave the

egg in a post-larval condition *.

This series of young 4. purpurea comprises the vast majority of the larve in the

collection, but in addition there are a few interesting Hippolytide closely allied to

Spence Bate’s larval genus Caricyphus. Only three larval Anomura are present; and

Brachyura are represented by a few metazoze and megalopee. Numerous examples of

all these larvee occur in our extensive material from the west coast of Ireland, and it

seems best to defer any detailed notice of the few specimens taken in the Bay of Biscay

until such time as I can deal with this large collection, which will probably enable many

of them to be connected with well-known adult forms.

* This statement is, however, incorrect: see note on p. 214.

SECOND SERIES.—ZOOLOGY, VOL. X. 35

206 MR. STANLEY W. KEMP—BISCAYAN PLANKTON:

All the specimens were taken in approximately the same locality, between latitude

46° 43' to 47° 29' North, and longitude 7° 15’ to 8° 18’ West. The soundings in this area

are 2000 fathoms or more.

MACRURA.

AMALOPENEUS ELEGANS, Smith.

Examples of this species are present in two hauls, the nets fishing between 350 fathoms

and the surface (36 Z), and between 1250 fathoms and the surface (27a). Three small

specimens were taken; two measure only 11°5 mm., and the third is broken,

Fragments of two individuals, which almost certainly belong to this species, occur in

another haul between 500 and 400 fathoms (85 4).

SERGESTES ARCTICUS, Kroyer.

Eighteen examples of this well-known N, Atlantic form are present in the collection ;

they range in size from 8 to 27 mm.: the smaller specimens have evidently only recently

emerged from the Mastigopus stage. One individual measuring only14 mm. possesses

antennze 54: mm. in length.

All the specimens which can definitely be referred to this species were caught between

100 fathoms and the surface, some actually at the surface. Fragments, in all probability

of §. arcticus, are present in nets fishing between 200 and 100 fathoms, and between

500 and 400 fathoms.

Larval SERGESTID®.

Two Acanthosoma larvee and several Elaphocaris were caught, all in the upper strata

of the water.

ACANTHEPHYRA PURPUREA, A. Milne-Edwards*. (Pl. 14 and Pl. 15. fig. 1.)

A mature male, 81 mm. in length, was caught in haul 360 between 100 fathoms and

the surface. The specimen may be referred to Coutiére’s var. muliispina ; the rostrum

bears ten teeth above and six below; the carinze of the last four abdominal somites are

produced posteriorly as spines, that of the third being the longest, the other much shorter

and subequal. The telson is furnished on the right side with nine, and on the left with

ten, dorso-lateral spinules.

More than fifty larvee of this species are present in the collection f; they range in size

from specimens which can only just have left the egg up to those which were described

by Coutiére under the name of parva. This author soon realised that he was dealing

with larval A. purpurea; and in a paper published shortly afterwards (Bull. Mus.

Oceanogr. Monaco, No. 70, 1906) he gives a complete account of the development from

* A full discussion of the somewhat lengthy synonymy of this species will be found in my paper, “ On the

Occurrence of Two Species of Acanthephyra off the Coast of Ireland,” Fisheries, Ireland, Sci. Invest. 1905, i. (1906).

+ In addition to those shown in the table of comparable hauls (pp. 216, 217), three specimens were taken in

21d, 100 to 0 fathoms.

DECAPODA. 207

the parva stage onwards. He did not possess any younger specimens, but suggested

that the earliest form was in all probability a zowa. The material in my hands enables

me to confirm this view. In the case of Acanthephyra (Systellaspis) debilis, a species

of which the development is now almost completely known, the larva is born with the

pereiopods fully formed and the pleopods present as buds; in this instance, however,

the ova are relatively of a much greater size than is the case with A. purpurea.

The following table shows some of the features of the specimens examined, excluding

those which were too broken to afford accurate data. The rostral length is subject to

considerable variation during the different stages: I have therefore measured the

specimens from the blunt tooth, which is situated at the base of the rostrum, to the tip

of the telson (excluding sete); in the younger forms this tooth is a very prominent

characteristic, and it appears to persist throughout the stages as the posterior dorsal

spine of the rostrum.

Bate ne. (tora. Stage. | Healt fees Stage.

22a 4:3 1. | No uropods or pleopods. 32 p 5:6 + Uropods free, no pleopods,

26 ¢ 4:3 4 * $ 301 5-7 a cA Bs

30f 4:3 3 ” 2 || 26a 59 t ” ”

36 f 4:3 i 2” ” | 301 5:9 7 ” ”

345 4-4 t ” ” 320 5:9 1 ” ”

3b4d 44 + ” ” | 365 6:0 z ” ”

33¢ 4:5 4 ” ” || 365 61 3 ” ”

26a | 46 + » ” | 32a 6:3 iu 5:

26a 46 + ” ” 801 6:6 4 ff 9

30f 46 4 p Ac 32m 6-6 a Aa is

8301 4:6 4 ” ” Nd!| ol x { With both uropods and pleopods ;

301 4-6 u 39 rf ee 0 eyes large.

30 1 46 a ” ” | 32 a 9-4 3 ” ”

301 | 46 | r “ | 259 |104 | 3 5 ‘

32p | 4:6 a 99 ” 25g | 116 B ap ef

36e 4:6 4 ” ” Nie? ie fe )| sail 4 “5

33 f 4:8 4 ” ” 25k | 12:0 4 5 4

264 5:0 4 es = || 32m} 12:0 4 a ds

301 5:0 q Uropods free, no pleopods. 382m | 121 4 5 A

34¢q 5:0 + » ” | 383g | 12-1 4 "7 Ps

36) 5-1 9 ” ” } 21m | 12:3 8 | Eyes small, “ parva” form.

30g | 52 No uropods or pleopods. || B4f | 125 6 Bs rs

301 5:2 , Uropods free, no pleopods. 32h | 130 - { With both uropods and pleopods ;

301 55 a ” ” aaa: 0 eyes large.

307 55 iy rE ” | 302 | 13:2 é 2 a

301 | 55 | 4 . %s | 25g | 184 | & % -

Tho figures in the second column can only be regarded as approximate, for the accurate measurements of

specimens possessing varying degrees of curvature is necessarily attended with some difficulty.

The smallest specimen in the collection measures about 4°3 mm., and there can be no

doubt that the larva is but little smaller than this when it leaves the egg.

As will be seen from the table, the collection contains nineteen specimens, ranging

from 4:3 to 5:2 mm., in which neither uropods nor pleopods are developed; these repre-

sent the earliest stage * in the metamorphosis (PI. 14. figs. 1-8, 11, 14, and 18).

* Tt will of course be understood that the word “stage” is merely used to distinguish larval groups differentiated

35*

208 MR. STANLEY W. KEMP—BISCAYAN PLANKTON :

The rostrum is very slender and nearly as long as, or rather longer than, the carapace ;

it bears a blunt spine at its base immediately over the posterior edge of the orbit. The

carapace is rather less than twice as long as broad; it is provided with a blunt spine in

the mid-dorsal line near the hinder margin, and occasionally with two or three extremely

minute spinules on the posteriot+basal edge; the orbital angle is obtuse and rounded,

the antero-lateral angle is produced forwards as a long, slender, upcurved spine.

The 3rd abdominal somite is deep, dorsally rounded in side view, and produced

posteriorly in the form of a hood over the 4th somite. The 6th somite is not marked

off from the telson; the two together are about four times the length of the 5th somite.

The telson (fig. 18) is wide, rather deeply emarginate apically, and is furnished on each

side with eight setee. The uropods are not free, but in some of the specimens, which are

evidently about to moult, they may easily be seen lying within the telson (fig. 19); in

these cases the telson itself is retracted somewhat from the outer edge, a fine filament

extending from it down each seta. :

The eye (fig. 14) is about as long as the carapace, and is widest across the cornea; the

latter is black and hemispherical, and is composed of approximately 200 to 300 facets.

Eight pairs of limbs are present, the antennules, the antennz, the mandibles, two pairs

of maxillee, and three pairs of maxillipedes. No pereiopods are developed in this stage,

but one or two pairs may be represented by_ buds.

The antennules (fig. 2) reach slightly beyond the eyes; the peduncle is in some cases

two-jointed, in others, in which development has proceeded somewhat, three-jointed. The

basal joint is long and shows no trace of the lateral process. The outer flagellum is

rather stout, not longer than the ultimate peduncular segment, and is furnished with a

few setee at its apex. The inner flagellum is represented merely by a rounded boss

bearing a stout plumose seta of varying length.

The antennz (fig. 11) scarcely reach to the end of the antennular peduncle; the

single basal joint is as long and as wide as the scale, the latter being elliptical in shape

and provided with 10 to 15 finely plumose sete; the distal spine is not present, and the

extreme apex is divided by two or three faint transverse articulations. The distal end —

of the basal.segment bears on its inner side a stout seta rather longer than the scale;

this doubtless functions as a flagellum.

The mandibles (fig. 3) show no trace of a palp, distally they are almost squarely truncate

and are provided with a few minute teeth. The 1st maxilla (fig. 4) consists of the two

basal lobes and anendopod. The lower lobe is rounded ard furnished with about six sete,

the upper rather longer with a narrow truncate apex armed with a few short bristles.

The endopod bears two sete at about the middle of its internal margin and four at the

apex. The 2nd maxilla (fig. 5) is widest basally, the internal margin is four-lobed, each

lobe being provided with numerous sete; the endopod also bears several sete, while

the oval exopod, which reaches to about half the length of the palp, is furnished with

five setee.

by sets of characters by which they may be readily recognized. The term has no special significance, nor is it

possible, in the present species, to say how many moults are included in each,

DECAPODA. 209

The three pairs of maxillipedes (figs. 6, 7, and 8) have long exopods tipped with three

or four long hairs. The endopod is four-jointed, the joints being narrow and subceylindrical,

and each provided with one or two setze. In the first two pairs the endopods are shorter

than the exopods, in the third pair they are equal, or the endopod is slightly the longer.

In the larger specimens in this stage buds representing the first appearance of the

two anterior pairs of pereiopods may be observed. Those of the first pair are longer than

those of the second, and are curved forwards between the bases of the outer maxillipedes.

In the next stage of the development the uropods are free, the telson is, however, still

more or less laminar, and the abdominal somites are not provided with pleopods.

Seventeen specimens with these characteristics, measuring from 5:0 to 6°6 mm., are

present in the collection (Pl. 14. figs. 9, 12, 15, 20, and 21).

The rostrum is relatively shorter than in the previous stage, being about two-thirds to

one-half the length of the carapace ; the large blunt spine at its base persists, and in one

of the specimens two very minute teeth are found in front of it. The blunt tooth in the

mid-dorsal line of the carapace near the hinder margin is still present, and a few very

minute teeth may usually be seen on the posterior basal edges. The characteristic hump

of the 3rd abdominal segment is more pronounced and elbowed than in the earlier stage ;

a notch is present in the mid-dorsal line of the 4th somite near the posterior edge, and

the 6th somite is about three times the length of the 5th. The telson (figs. 20 & 21) is

still somewhat foliaceous and is subparallel, or rather wider at the apex than at the base.

Distally it is emarginate, and, as in the earlier stage, bears eight pairs of sete. The

uropods are free, the outer in the older specimens bearing a spine on its outer distal edge.

The endopod is at first short, but rapidly attains to the same length as the exopods.

The eye (fig. 15) has not kept pace with the growth of the carapace, being now little

more than half its length; the cornea is still the widest part. The basal joint of the

antennular peduncle is very much longer than the 2nd and 8rd combined; it possesses

no lateral process, but is proximally somewhat swollen on its outer edge. The outer

flagellum is still quite rudimentary, being little longer than the ultimate peduncular joint ;

it bears a long apical seta. The inner flagellum has now appeared and is about half the

length of the outer; the long seta present in the earlier stage has been carried up on its

apex. The antennal scale (fig. 12) is longer than the one-jointed basal segment and reaches

to the end of the 2nd joint of the antennular peduncle; it is furnished with numerous long

setze and with a stout spine at its outer distal edge. The long seta which represented

the flagellum in the previous stage has disappeared and a short thick protuberance, from

one-fifth to one-third the length of the scale, has taken its place.

During the course of this stage the first three pairs of pereiopods with their exopods

are developed ; in structure they resemble the outer pair of maxillipedes,

All the remaining specimens in the collection, with the exception of two measuring 12°3

and 125 mm., belong to the next stage, in which uropods, pleopods, and all five pereiopods

are developed, while the eyes remain of relatively large size and are widest across the

cornea. These specimens measure from 9°1 to 13-4 mm. (PI. 14. figs. 10, 13, 16, 22,

and 28),

The rostrum is less than half the length of the carapace and is furnished dorsally with

210 MR. STANLEY W. KEMP—BISCAYAN PLANKTON:

from three to five teeth, the posterior of which, although in some cases small and sharp,

appears to represent the blunt spine present in the two preceding stages; ventrally the

rostrum is unarmed. ‘The median spine at the posterior edge of the carapace persists,

although of comparatively small size, in the larger examples; the minute spinules on the

inferior hinder margin of the carapace are present in the smaller specimens only. The

elbow on the 38rd abdominal somite is as prominent as in the preceding stage, and the

6th somite is two and a half times the length of the 5th or slightly more. The telson

(figs. 22 & 23) is at least three and a half times as long as wide; in younger specimens it

is apically emarginate, in older forms more or less truncate. Of the eight original pairs

of setee, two have been carried up the sides of the telson and have become dorso-lateral

spinules, others being added during succeeding moults. The apex is thus left provided

with six pairs, two of which, the second and fourth counting from the outer angle, are

now much stouter and longer than the rest.

The eyes (fig. 16) are still relatively large, one-half the length of the carapace or rather

less ; as in both the previous stages, the cornea is by far the widest part. The basal joint

of the antennular peduncle is proximally much widened on its outer edge, this widened

part being produced forwards to an acute point representing the lateral process; this point

does not reach forward more than one-third the length of the basal joint. The two

flagella in large specimens are about equal and almost as long as the peduncle. The

antennal scale (fig. 13) reaches almost to or beyond the end of the antennular peduncle:

the flagellum is of varying length, in large examples reaching as far forward as the

flagella of the inner antennze; it possesses two well-marked basal segments. The

antennal peduncle is two-jointed,

All the five pereiopods with their exopods have now appeared. Pleurobranchs are

present at the base of all five, the arthrobranchs being still rudimentary and represented

by buds. Epipods are in evidence at the base of the first three pairs. The legs are all

of roughly the same length and are but little longer than their exopods; their respective

joints bear much the same proportion to one another as those of the adult, with the

exception of the dactylus of the 5th pair, which is as Jong as that of the 4th. The first

two pairs are not chelate and no traces of the spines on the inferior border of the ischium

and merus of the last three pairs are yet to be observed.

The two remaining specimens in the collection, of 12'°3 and 12°5 mm., represent the

post-larval stage to which Coutiére has given the name of “parva” (Pl. 14. fig. 24;

Pl. 15. fig. 1). The smallest specimen of this stage that he found measured only 10°5 mm.

Tt will be seen from the table that some examples in the previous stage attain a length of

over 13mm. This very considerable overlapping of the lengths of the oldest larval and

youngest post-larval stages is remarkable, but when the extraordinary variation of the

adult is considered it must be admitted that it would be even more remarkable if some

sort of variation did not also extend to the development.

By far the most noteworthy feature of the change to the parva form is the great

reduction of the eye (fig. 17) *. It is now less than one-third the length of the carapace

and the cornea is not so wide as the stalk. A rather obscure convex dise situated on the

* Figs, 14, 15, 16, and 17 are drawn to the same scale and show the growth and subsequent reduction of the eye.

DECAPODA. 211

upper interior portion of the stalk near the cornea represents the first appearance of the

ocular papilla.

The rostrum is now not much more than one-quarter the length of the carapace;

dorsally it is armed with from six to eleven teeth ; ventrally it is at first unarmed, teeth

however, soon appear in the form of nicks in the thin margin. The blunt dorsal spine

near the posterior margin of the carapace is still present, but it is still quite rudimentary

and shortly disappears. The 6th abdominal somite is less than three times the length of

the 5th, and more dorso-lateral spines appear on the telson (fig. 24), the terminal spines of

which have all disappeared, with the exception of the two large pairs and one small one

which has taken up a central position.

The oral appendages have now assumed a form closely resembling those of the adult,

and the first two pairs of pereiopods have, by an outgrowth of the propodus parallel to

the dactylus, become possessed of chelee; these, however, in smaller examples are still

quite rudimentary. The ischium and merus of the last three pairs bear a few spines on

their inferior border, the full complement being formed subsequently.

The growth of the rostrum and other changes which the parva form undergoes before

finally attaining its full dimensions have been adequately treated by Coutiére (Joe. cit.).

The most interesting and remarkable feature of the metamorphoses of A. purpurea is

the reduction and subsequent growth of the cornea and rostrum, In the youngest stages

the rostrum is long and is gradually reduced in size until a minimum is reached in the

“parva” form, from thence onwards it grows with each succeeding moult until the adult

form is attained. In old specimens the extreme apex frequently appears to be worn

down and is thus to some slight extent again reduced.

The development of the eye is somewhat different ; it shows a gradual growth with an

increasing number of facets and is widest across the cornea until the “parva” form is

reached. It is then suddenly diminished in size and the cornea becomes narrower than

the eye-stalk ; the number of facets has nevertheless very considerably increased. By

subsequent growth the eye at length reaches the adult condition with the cornea once

more wider than the stalk.

All these young specimens were caught between 100 fathoms and the surface, with

the exception of the two referable to the post-larval or ‘‘ parva” form; these were taken

between 750 and 500 and between 500 and 400 fathoms respectively *.

The frequent occurrence of the larvze of this species in the upper strata of the water

and the apparent absence in that horizon of the post-larval forms seem to suggest that

at the approach of the “parva” stage the animals descend to what is probably the normal

* (Treated as in earlier papers of this series, these larvae

2 ee EY 0 NS.

Z 2 | & | 25 = | 05 | #8

3 ps .- Ba

S 50 = 69 }) # 18} &

a ors S

E iw | ai x of

100 / Oe = Vor) 5 &

/ 3

Both sets of figures point to 50 fathoms being the preferred horizon; but the total numbers are unfortunately

small.—G, H. F.]

212 MR. STANLEY W. KEMP—BISCAYAN PLANKTON :

level of the adult. The evidence is, of course, far from conclusive and other records of

the post-larval forms throw no light on the subject. Coutiére’s specimens were caught

in vertical nets at two stations, the hauls being 1000 m. to the surface and 3250 m. to

the surface; those taken by the ‘Helga’ off the Irish coast were captured in a mid-

water otter-trawl, which was iowered to about 350 fathoms, the net fishing while being

hauled to the surface.

Even in the ease of the adult, a Macruran of almost world-wide distribution, but little

is known of the bathymetric range. The adult male present in this collection was caught

between 100 fathoms and the surface, a young male was caught off the American coast

actually on the surface, while the species has been trawled between 107 and 2949

fathoms. The probability, in the latter case, that the specimen was caught during the

ascent of the net renders it and similar records almost worthless from a bathymetric

point of view. The solution of the problem is to be sought either in successive hauls to

the surface from varying depths of wide-mouthed vertical nets, or, more certainly, by the

use of a self-closing net of very large dimensions.

ACANTHEPHYRA DEBILIS, A. Milne-Edwards.

A mature male, 67 mm. in length, was caught in haul 80 m, between 25 fathoms al

the surface. The basal crest of the rostrum bears four teeth, the rostrum itself being

furnished with twelve teeth above and eight below.

The specimen, which is preserved in formalin, has retained a considerable amount of

the deep scarlet-red pigment so frequently met with among deep-sea Macrura, and the

numerous luminous spots and streaks so fully described by Couticre (Bull. Mus, Oceanogr.

Monaco, No. 70, 1906) are well shown. ‘The distribution of the red pigment in connection

with these presents features of some interest. Over each photophore is seen a small

clear area, quite devoid of pigment, forming as it were a small window to allow of the

passage of light outwards. These transparent are areas of similar shape to the

photogenic spots over which they are placed; over single round photophores they are

round, over the prominent vertical Juminous organ which is situated behind the 5th pair

of thoracic legs there is a quite large elliptical area, while a narrow transparent line is to

be seen over the row of closely approximated photophores along the anterior basal edge

of the carapace.

A. debilis is apparently a somewhat rare species and has been recorded from depths of

350 to 2512 fathoms. These captures were made with open nets and are consequently

of little value for the determination of the bathymetric range ; still it seems certain that

the present specimen was far above its normal horizon.

The occasional appearance at the surface of species normally frequenting deep water

is a phenomenon of considerable interest. It has been suggested that the females rise to

the surface to liberate their eggs in order that the larvee may have warmer water in

which to undergo their metamorphoses and a better chance of distribution by means of

ocean-currents. Jn the present species, however, the young leave the egg more fully

developed than is the case with A. purpurea, presumably that they may be enabled to

survive under conditions which would prove fatal to a zozea. yn

DECAPODA, 2138

HiyMENODORA GLACIALIS (Buchholz) ?

Macerated fragments from haul 266, 2000-1500 fethoms, may almost certainly be

referred to this species. If correctly determined, the record marks the most southern

limit in the known distribution of the species.

Unknown larva allied to Cartcypuus, Spence Bate. (PI. 15. figs. 2-8.)

The whole animal is strongly laterally compressed ; the rostrum unarmed and slender

and about two-thirds the length of the carapace. The carapace itself is more than three

times as long as deep, carinate on its anterior third and furnished with a blunt spinule

behind the orbital notch; it is extended as an acute point above the insertion of the

antennz and the anterior basal edge is marked by a short slender spine.

The last four abdominal somites are dorsally carinate, the 3rd is very pronouncedly

elbowed, the segment extending to an acute hump, forming a most prominent feature in

side view ; the 6th somite is rather more than two anda half times the length of the 5th.

The telson (fig. 8) is almost twice the length of the 6th somite, apically it is rather broad,

somewhat truncate, and furnished with five pairs of spines, the second pair counting from

the outer edge being very much longer than the rest. Laterally it bears five or six pairs

of spinules.

The eye is not one-third the length of the carapace; the cornea is very large, somewhat

elliptical, and set obliquely on the stalk. The basal joint of the inner antennze reaches

to the distal extremity of the eye; proximally the segment is laterally expanded and in

larger specimens there is a small acute point projecting forwards forming the first

beginnings of the lateral process. On the inner side of the joint at about its middle are~

set three rather long forwardly directed spines. The 2nd joint is somewhat longer than

the 3rd and the outer flagellum is at its base considerably stouter than the inner. The

antennal scale reaches slightly beyond the peduncle of the inner antenne ; it is narrow

and bears the usual spine at its outer distal edge.

The mandibles (fig. 3) show both molar and cutting edges, the latter being furnished

with three strong teeth. In the first maxille (fig. 4) the basal lobe is broad and bears

many sete, the upper lobe being narrower and provided with stiff bristles. The endopod

is one-jointed and is furnished apically with three stout sete, while from a tubercle on

the inner side two others arise. The basal portion of the second maxilla (fig. 5) is

internally trilobed and setiferous; the endopod is short, one-jointed, and bears apically

five or six setze, while two or three others are situated on two prominences on the inner

aspect. The exopod is long and narrow, externally it is slightly concave; the anterior

lobe projects forward about twice the length of the endopod, the narrow posterior lobe

being about half its length. The margin is uniformly clothed with fine sete.

Both basal joints of the first maxillipede (fig. 6) are broad, the second being densely

clothed with setze on its inner edge ; the endopod is three-jointed and bears few sete. The

exopod is slender, about three times the length of the endopod ; it is divided distally into

several annulations. The epipod is bilobed, the lower lobe being the larger. The second

maxillipedes (fig. 7) possess a five-jointed endopod, an exopod which is slightly shorter

SECOND SERIES.—ZOOLOGY, VOL. X. 36

214 MR. STANLEY W. KEMP—BISCAYAN PLANKTON:

and very slender, and a large epipod. A small leaf-like extrusion at the base of the

epipod may represent the first appearance of a podobranchia.

The third maxillipedes and first four pereiopods are provided with long setose exopods.

The fifth pair are much shorter and possess no exopods. None of the legs show any

signs of chelze and the dactyli in all of them are minute. Short pleopods are present in

specimens measuring 23 to 25 mm., in a specimen of about 15 mm. they are quite

rudimentary.

Four specimens of this larva measuring from 15 to 25 mm. are present in the

collection. ‘Two were caught between 50 fathoms and the surface and two between 100

fathoms and the surface (21 d).

Although in general aspect this larva bears some resemblance to young 4. purpurea,

the absence of an exopod on the last pereiopod proves there is no close affinity between

them. They closely resemble certain of the immature forms described by Spence Bate

(Chall. Rep. 1888) under the name of Caricyphus, which have since been considered to

be larval Hippolytidee ; it is, however, probable that young individuals of several genera

are included under this name.

ANOMURA.

A Pagurid metazozea was caught between 100 fathoms and the surface ; the specimen

is unfortunately dry.

Two other Anomurous larvee were caught between 75 fathoms and the surface:

numerous specimens of this larva and of some of its later stages have been met with

off the Irish coast ; it therefore seems best to defer any account of it until opportunity

occurs of dealing with this more abundant material.

BRACHYURA.

Three metazozeze were caught between 50, 75, and 100 fathoms and the surface and four

megalopze occurred at the same depths.

ADDITIONAL NOTE.

Since the above was written, a specimen of Acanthephyra debilis, only 10°2 mm. in length, has. been

found off the W. coast of Ireland. This specimen, which possesses only six pairs of photophores, is very

different from that figured by Coutiére as the form in which the species leaves the egg. The rostrum is

scarcely longer than the eyes, the pleopods are short and bud-like, no uropods are developed, and the

telson is broad, rounded, and apically emarginate, as in young A. purpurea. All the pereiopods are

developed, and a bud at the base of each represents the first appearance of a pleurobranch. _

Although the discovery of this specimen shows that the differences between the earliest forms of

A. purpurea and A. debilis are less than was previously thought, there is still evidence to show that the

A, debilis larva is much the more advanced of the two, for all its pereiopods are formed and the pleopods,

although rudimentary, are not totally undeveloped. j

[September 1907.]

DECAPODA.

EXPLANATION OF THE PLATES.

Puate 14.

Acanthephyra purpurea, A. M.-Edw.

Fig. 1. Zowa measuring 43 mm. side view, right eye removed.

. Antennule of zoza.

. Mandible of zoza.

. First maxilla of zozea.

Second maxilla of zoza.

. First maxillipede of zozea.

. Second maxillipede of zozea.

Third maxillipede of zoza.

( ONO oe OF ~

10. Larva measuring 10:4 mm. ; side view. i

11. Antennee of zoza. Ao Li

12. Antenne of larva measuring 6 mm. \z

13. Antenne of larva measuring 10°4 mm. sg

14. Eye of zoza.

15. Eye of larva measuring 6 mm.

16. Eye of larva measuring 10°4 mm.

17. Eye of post-larval or “parva” form.

18-24. Development of telson and uropods: fig. 18, telson of zoea; fig. 24, telson of “parva’’ form.

| Drawn to the same scale.

Puate 15.

Fig. 1. Acanthephyra purpurea, A. M.-Edw., post-larval or “parva” form.

Larva allied to Caricyphus, Spence Bate.

Fig. 2. Side view of a specimen measuring 22 mm.

3. Mandible.

4, First maxilla,

5. Second maxilla.

6. First maxillipede.

7. Second maxillipede.

8. Telson.

NOTE ON DISTRIBUTION.

By G. Hersert Fowuer, Ph.D., F.L.S.

In the following table of “comparable hauls,” in the column headed Acanthephyra

purpurea, A = adult, P = “ parva ”-stage.

¢ ; é Pa pe ereele %

. Larva measuring 6 mm.; side view. AwrG 08 kg

216 MR. STANLEY W. KEMP—BISCAYAN PLANKTON:

Depth in

fathoms. Haul.

elegans.

arcticus.

Sergestide.

purpurea.

Amalopeneus

Sergestes

Acanthephyra

debilis

Hymenodora

glacialis

Larval

| Acanthephyra

500—250 94

1500—750 20a

2000—1000 30

0 2Qle

339 a 4 ‘i '

50—0 Dg

HH oo

Pte:

whon

tre ae J : 4

2: See. bo Pee ee

Caricyphus.

Larval

Anomura,

Larval

Brachyura,

Depth in

fathoms.

100—0

150—0

1 ‘| 150—50

eee 150-100

200—0

200—100

ys 250—0

— | = 250—150

Haul.

Amalopencus

guns:

Sergestes

arcticus.

DECAPODA.

Sergestidee.

Larval

| Acanthephyva

purpurea.

—

debilis.

Acanthephyra

Hymenodora

glacialis.

Caricyphus.

| Larval

Anomura.

Brachyura.

Larval

ae ee

oe (==>

—— e-

=» ¥

— a

KEMP. TRANS. LINN. SOC. SER. 2, Zoo. Vol.X, Pl. 14.

C, T. Kemp, del, JT Rennie Reid Lith Edin”

DECAPODA FROM BISCAYAN: PLANKTON.

— 2 SS ee MT i Res PON ol ye 8) |

. t bas > rh ae rea

TRANS. LINN. SOC. SER. 2, ZOOL. Vol.

KEMP.

J.T Rennie Reid, Lith Edre”

BISCAYAN PLANKTON.

DECAPODA FROM

BISCAYAN PLANKTON.

Part XIL—Tun OSTRACODA. oe ADDY

By G. Herzert Fowter, B.A., Ph.D., F_L.S. tee IBRARY

(Plates 16-27.)

Read 3rd December, 1908.

ConTENTs. Page

PeeeIntroductiongerscy vy ceteetclexs cis.0 +e 1a ss-ce-sicre atc emeneorenerelsielemetetsadinisieisis siegel 220

Comparable and Non-comparable Hauls ..............-+.eeeeeeeeees 221

Manipulation tye aejcten es cos: e1 =) ans, 0 6) svcas es ereepnedtermnsitais catetelersrelsi.rs ao

The difficulty of linking together successive Stages ...........0-0++-- 228

The argument from constant association ........-.00- eee e eee eee) 223

The mathematical relation between different Stages: Brooks’s Law...... 224

Conchorctusimprtcdte asian CXAMPIE «../s= (7-1 s/atetetetalelsel-fse a=) er stefals elaherelel te 224

SIEM Sy Sbemati Ceanbamerttselexeiaic << 4 «vous = ose /eisial tele pete reneteteneerenst=teie)cratela a elel> 227

GithiliGiel SCS Solceeecseeeanmors od b0cr06 co duicocuCerconse oe 227

Halocy pride: < <clee. s 26 a2 ss x 5/2 's) s/s! a) ofletenerorstohskeneareteiotereefers soo oomade 228

hexaGroupsysreprosented ...... «manasa amet eaten toils 20

Cyr imidaaigmmyertsectletenclo: « <1 <1si « » o/oicre stetventekesetaratelehotete fetarersferatehe =e /oe = 257

Hehe D) SvelopmentallPartipeeicys cleinas\+l<:s > o/c) oreleve/eietetetarsveletefelelstete HG FOO COIS 257

LILO WOE 46 on CO CObROCOORAOOOeOODOOC.0 na On onticaoUs oOCoeg Maeno ne 259

(ri oNG GE) -oncn go DAO RE ODOMGEE Od 000° 00.00 0d Guo obhcoodormasn eaAY

Herrick’s records of Homarus americanus ......cececeecceeecevesees 279

MIGHSULGMEN SOL OCArCiNUs MENA . « «oi wmiaqaieielel eieicleleisiniesiersle cies wees ZOO

General course of the development ..........cscccececcscccsscccecs 281

IDV Wau Wis tek attra nas « crsr sia, 61) <:s\crg,c\0: +, <= v-0!s Clee eeere mm rrete tele eelsievel ess <i = e0.sl 202

The difficulty of determining the lower limit of Species .............. 282

Halocypride ........... JOOP ERECOBION DOO! mo ODIOG Ole COC CEO UO ODEs.

Gi yaVtin OL aege dct one! siate aie” avs) ola, 0° avnis, o)ace Searee eteecteteel el Seisielave 2's ales <i 200

The Vertical Distribution of Ostracoda as a whole..............ee000: 296

Suggested zone of diminished sinking-velocity .................... 297

FHI XPLAMEUOMPORMELSEA:D¢. .s sicle ayascveie atevets ateteta atefedateda ofetelaiel eiel slers)siaie as 298

The Vertical Distribution of individual Species ...............e ee cees 300

IDGHMUELGONODSCEVALIODS, «ve: « w «sluts dehaleiea mastic eels sisisie cee ses 300

The Vertical Diurnal Oscillation of the Epiplankton .................- 302

Supposed movement of Concharcia curtd .... 6 cece e eee c cee ee ee eees 303

Simultaneous and consecutive Hauls ...........see cece ceeeeeeees 305

Haul 27 @ and/Open. Vertical Nets .....e.cicjescwnciicesiecssccsecscees 305

Nite MIScellHNEOUBSINOGOS <2 41s +.</0 <<: <10,n10, 0; 016sig/e/sainppniaMe pot aia/slovaa wie ee 0a «ous is 308

BTorMnomron Neales to Hemales .. <0 -cilsignniad eee cree veer ce svc 308

PTE PSM ET ALG 7 e) c,c( x0 (arele'a« a:6 a) sialsie) «Shami eeReKeRMenGePaiers) Wis) oe © = ares asia aie 309

The occurrence of closely allied Species in the same water ............ 310

VI. General List of Species by hauls and depths .............++05 Aeornetc 311

SECOND SERIES.—ZOOLOGY, VOL. X. 38

220 DR. G. H. FOWLER—BISCAYAN PLANKTON :

Index to the Species.

Systematic. Developmental. Faunistic.

I. Hatocypripz.

| (1) Concheecia. Page Page Page

Le ametra, Mallen. ies usiesein tee oer 229 | 259 283

2. brachyaskoss Meller sn 0 eceeraeneeiers 231 259 284

Bs CUIELA. EALDOOCIE! pice ek Pins ec eee 231 259 284

4‘ daphnoidess Olatsien a. arse sac 233 261 285

De ClEZANS WINES) Meee ele acre ae 233 263 286

6. haddoni, Brady and Norman.......... 235 264 287

a. byalophyllumyiGlausl cna e eee 236 265 287

8. imbricata (Brady, pars), Miller ...... 238 224, 266 288

Op umermis.Clausi Martone nek ee octet 239 267 288

IOS kampta, Miller <2. 2 4. - ace eee . 240 ys 288

dul MloricatasiClais ates sete et ea eee 240 267 289

UP ECA (OM bone bowob 8 wu oulnded 3: 242 268 289

SCAM Nar yie. ie cuba ttancacelt ce enna eee 245 270 291

GE OA WMD Soe boc onbdadcnagbacc 246 270 292

VAS pusilla Millers isaac eae ne eee 247 272 292

oa hiynchenasaeler ne ayaa ses ae eee 248 272 293

Gp rotundatas Mellons. wie aaten ene 249 273 293

Lifemspinicera| OUcusmsee jake cee eee 234, 251 274 294

UES Goumeooey O07) soacnesdgeqone a4 Z 252 276 294

LO byloda. Muller” Naits cele sc cre rncra se ee 253 ee 295

20) ZEtes1OS SPsMse ecvedon ad A Gitteaet Se 254 PAT 295

Pil, Mls} shyOPbE, oancoondsouscuco ay 254

22 AC Sainnominatay seer ese eeere 255

(2) Halocypris.

sme lobosanOlanesten nt: Heine sinters ae eee 255 277 295

(3) Archiconchecia. |

2H CUOGWIEE RSG) paoaanonodaeocunet 256 279 296

II, Cypripjnipz.

(4) Cypridina.

Zo Castanea, Brady... i, 4 is <9 «ie erietneee 257 279 296

(5) Gigantocypris.

Dornelincidase Mullery wacvacesaee eee 257 oe 296

jes

I, INTRODUCTION.

THE study of the Ostracoda collected during the 1900 cruise of H.M.S. ‘ Research ’

proved to be an arduous undertaking. More than 7000 specimens have been identified ;

and in more than 3300 specimens the sex has been determined and the antero-posterior

length of the shell measured. The results are such that one need not grudge the time

and labour involved, for the neglected little family of Halocypride, by the number of

its members and by its presence at (apparently) all depths, affords admirable material for

the study of oceanic problems. Thanks to the labours of Professor C. W. Miiller, of

Greifswald, the species are now more or less orderly arranged, and the difficulties

of manipulation are only serious in the case of the minuter specimens of less than

one millimetre.

THE OSTRACODA. 221

CoMPARABLE AND NON-COMPARABLE HAULS.

The comparable hauls of Ostracoda in the epiplankton were only 65. All hauls

with nets of 18 or 180 meshes to the linear inch were omitted: the former allow small

specimens to slip through; as regards the very fine-meshed nets, it has become clear in

the course of the study of the Biscayan material that they are perfectly useless for a

proper representation of the macroplankton, presumably because the frictional resistance

of the meshes is so high, that such nets simply push the water in front of them aside

and allow very little to filter through them. A few more of the hauls have been rejected

because the material had been allowed to dry, because part of the catch had been

lost, &c.

Of the serial hauls 36 e to 361, the deepest (36/) has been completely worked out

for specimens over 1 mm. in length; of the other non-comparable hauls only 27 a

(1250-0 fms.) has been completely worked out. There are limits to human patience,

and mine had been already reached when 36d was finished. In some cases, however, of

the rarer species, the non-comparable hauls have been gone over roughly in order to get

more specimens for measurement ; these specimens appear in the tables of lengths, but

not in those of distribution.

MANIPULATION.

The chief difficulties with an Ostracod are to hold the little bi-convex shells steadily for dissection,

and to get them exactly into a horizontal position for drawing and measurement. ‘The tools needful are

a pair of mounted needles, the one blunt, the other as sharp as constant grinding will keep it; and a

microscope slide in which a convex hollow has been ground, such as is used as a “cell” for mounting

thick objects.

The first thing is to get the specimen (if unfamiliar) into the right horizontal position for observing

and drawing its contour : it is put into the hollowed slide, and all superfluous fluid removed with a fine

glass pipette; this method is most useful, because the remaining film of fluid tends to hold the animal

steady by surface-tension. The animal is then pushed up the side of the cell, the curve of the hollow

being utilised to tilt it into exactly the right position with certainty. In the case of nearly spherical

forms, such as globosa ? , the animal can be supported by two fine threads of drawn glass in the

required position. The shape of the shell, which can now be accurately observed, yields on the whole

the most satisfactory specific character, and generally points to one of at most some half-dozen of

species. As far as possible, the contour should always be studied and drawn before dissection; the

contour should never (if avoidable) be drawn from inside with the shells opened out flat, as this

procedure produces distortion near the hinge (dorsal border). The openings of the asymmetrical glands

should then be considered (the opening of the left gland of rotundata can rarely be seen except from

the left side with the specimen strongly tilted ventrally).

After this, it is generally necessary to open the shells. Again utilising the surface-tension of a thin

film of water, the animal should be put on its back and held with the blunt needle, the sharp needle

inserted, first between the shells, and then between the left shell and the body, until it is possible to

make a cut with it through the occlusor muscles: the left shell can then be hinged back, cutting with

the needle through the internal lining membrane if tough. Holding the animal with the blunt needle

about the middle of the body, cut with the sharp one round the base of the large muscle of the second

antenna; this appendage can then be hinged back, without being absolutely detached. All the

38*

222 DR. G. H. FOWLER—BISCAYAN PLANKTON :

important organs required for specific identification (thanks to Miiller’s investigations) are then

exposed to view; and the frontal organ should be drawn in situ, to ensure a true profile. When the

specimen has been identified, the left antenna ii can be pushed back into position and the shells closed ;

the specimen is none the worse for the operation. For the determination of sex it is better to turn

back the left shell than the right, as the penis lies on the left side. In the youngest stages, however,

this organ is represented only by two rudimentary buds, and it is not always possible to make sure of

its presence or absence; nor can the appearance of the immature generative glund be relied on to settle

the sex; in such cases the characters of the flagella and sense-tubes of the first antenna generally give a

clue, except in the very youngest stages.

The measurements of the shell-length have been taken whenever possible from the inner aspect of the

right shell with the left shell turned back, as this is the less likely to be distorted by the dissection.

They were taken with Zeiss micrometer ocular 3, in combination with objectives a’, a’ (with tube at 0 or

at 21 mm.), and A; the value in p of 20-60 divisions of the ocular micrometer, for each objective

and stand used, having been determined by a stage micrometer. The measurement was made parallel to

the dorsal border from the most prominent part of the anterior border, ventral to the niche for the second

antenna*,

Appendages should always be drawn in the preserving fluid (formalin or alcohol) and before mounting,

in order to get full advantage of differences in the refractive index, when dealing with fine hairs or

teeth. If it is desired to mount appendages permanently for reference, Farrant’s solution “ringed”

with gold-size may be recommended.

No one knows better than the writer that the present memoir is full of unproven

assumptions and of arguments ina circle; for these he offers no apology. There is no

harm in such assumptions so long as it is made clear to the Reader where fact ceases and

hypothesis begins, and so long as the evidence which has sugzestzd the assumptions is

put fairly before him for his private judgment.

It seems to me quite certain that we shall make no alvance in serious ozeanic

planktologyt by the methods (or rather, lack of methods) which have hitherto prevailed.

No amount of hauls with vertical open nets, no nunber of handsome Reports on barren

systematic morphology, will further our grasp of this branch of Natural History. If my

assumptions do but stimulate some one to go to sza in order to disprove them (criticism

ashore is too facile) they will have served their tura, be they right or wrong.

In his great work on the Ostracoda of the ‘ Valdivia’ Expedition, Dr. Miller { brougat

out the fact that the contour of the shells, the position of their glands, and the characters

of the cephalic appendages (frontal organ, antenna i, antenna ii) are usually sufficient

for the recognition of the species. But, unfortunately, except for the shell-contour, the

characters which he gives apply only to sexual stages, and are useless for immature

* This gives a real measurement of the shell, which is comparable in different species. Some previous observers

have measured the length from the tip of rostrum to tip of posterior spine, thus obtaining measurements which are

not expressions of the general body-length.

+ Neritic planktology with economic aims is on a different footing.

+ ‘Wissenschaftliche Ergebnisse der deutschen Tiefsee Expedition auf dem Dampfer Valdivia, 1898-1899, vii, 2.

C. W. Miiller: Ostracoda. Jena, 1906. In the following pages, where “ Miiller” alone is mentioned without

citation, the reference is to this work.

THE OSTRACODA. 2238

specimens. The further that we go back in the ontogeny, the more do the organs in

question resemble one another; even the shell-contours of different species tend to

converge towards a common and, presumably, ancestral type. Dr. Miller made no

attempt to define the characters of the early stages, although they can hardly fail to

have been present in large numbers in the collection.

In handling large collections from tropical or subtropical waters (such as those in

which the ‘ Valdivia’ very largely worked), owing to the great number of species present

in a haul and to the scattered nature of the stations, it is far more difficult to make due

allowance for such perturbing factors as variation, developmental changes, and sexual

dimorphism, than is the case in temperate or sub-polar waters; for in these latter the

large number of specimens but a comparative paucity of species are more characteristic.

In other words, the argument, that two very similar forms (whether male and female, or

larva and adult) are likely to belong to the same species because they are constantly

associated together in the collections, is far stronger in temperate than in tropical seas.

Probably all who have worked over large plankton collections from temperate waters

will agree, that very closely allied species—species studied in the detail which has

become necessary in such groups as Copepods, where a few hairs more or less may turn

the scale—are rarely found together at the same horizon (sea-climate) *. In tropic

waters this is apparently not so marked. Too much stress must nut be laid on what may

be called “the argument from constant association,’ but it is no doubt of considerable

value in dealing with southern or northern collections such as the present.

Again, the purely local nature of the present collection is a great help; in the com-

paratively scattered collections of the ‘ Valdivia,’ which probably met a fresh combination

of species into the fauna at nearly every station, it would have been almost impossible

to have worked out the relations of larvee and adults; in the small area studied by the

* Research,’ where the general combination of species to form the local fauna hardly

varied from day to day, it is far easier to connect together successive stages of the

‘same species.

Consequently an attempt has been made in this Report to link up larve and adults

wherever practicable. Until this has been done, it is dangerous to use Ostracoda as

counters in a discussion of problems of oceanic distribution. For, although the younger

stages of many organisms appear to react to their environment in a manner different

from their adults, still this cannot be taken for granted in every case without proof.

As in the case of some other groups already described, I have tried to sort out from

the general collection every specimen of an Ostracod captured. With the minute

specimens of less than 1 mm. in total length, this is of course really impracticable.

But, as I have already pointed out (pp. 7, 93), the error will merely underestimate

the difference between abundance and scarcity, and is therefore an error on the

safer side.

The difficulty in connecting immature larvz with their sexual adults in Ostracods and

-other Crustacea, lies in the alteration of the form of the shell and appendages at each

* An apparent instance, however, will be found below in Conchecia magna and zetesios (p. 310).

224 DR. G. H. FOWLER—BISCAYAN PLANKTON:

successive moult (or at least each growth-moult). Fortunately, the shell-contour in

Halocypridze does not alter so much as the principal organs: it does alter somewhat

in most of the species studied below, but more gradually and to a less extent than do

the cephalic appendages adopted by Dr. Miiller for diagnosis.

Something more, however, than a general resemblance of shell-contour is necessary

in order to link up securely older and younger stages of a species. The clue, which for

some time I sought in vain, is to be found in an observation of W. K. Brooks*. He

noticed, in four specimens of Stomatopod larvee captured at St. Vincent, a curious

mathematical relation: that if the length of the shortest larva, 4°16 mm., be multiplied

by {, and the product by {, and so on, the following numbers are arrived at :—5°20, 6°50,

8:13, and 10°16 mm. ; and his other three larve were actually 5:29, 6:49, and 10°21 mm.,

the 8:13 stage not having been captured.

I have developed this relation for Halocypride in the following pages, and propose

that it should be termed ‘“ Brooks’s law,” in honour of one of the most ingenious of recent

naturalists. If it prove to be truc in other Crustacea (as I expect, having tested it in a

Macruran and a Brachyuran), it could be phrased as follows :—‘ During early growth,

each stage increases at each moult by a fixed percentage of its length, which is approxi-

mately constant for the species and sex.” In Halocypride this percentage differs in

males and females, as the egg is presumably of the same size in both sexes, but the

males are ultimately shorter than the females of the same stage in nearly every species

and group.

I am well aware that a great many more instances must be recorded before this

proposed ‘“‘law” can be accepted, even with probable modifications, but I have over-

emphasized it in order to call the attention of students to the necessity for testing it

wherever possible. If it proves to be general, it will be of great value to the plank-

tologist, as helping him to connect the swarms of larve in a neritic haul with each other

and with their adults.

It will carry more conviction, if one takes for the first illustration a species with a

quite unmistakabie shell-contour such as Conchecia imbricata (figs. 110-121, Pl. 20).

Of this species only a few specimens were captured, but by selecting imbricata, though

the mathematical completeness is less, the zoological certainty is greater; and it will

serve as well as any other species to demonstrate the simple mathematical methods

employed.

When all available specimens of imbricata had been measured and sexed, they formed

the following series: the number of specimens in each sex at each length being placed

opposite to that length.

* Report H.M.S. ‘Challenger’: Zoology, xvi. The Stomatopoda, p. 105.

THE OSTRACODA. 225

OF mn. 3.

{ 3 2°5

Stage II.

Mean, 2°34 mm.

= =

| Stage II.

| Mean, 2:01 mm.

me or oo

Wey 1)

io) 6 1 { Stage III.

Stage III. | 7 Te 7 | Mean, 1:48 mm.

Mean, 1:50 mm. [ 9 Tad! 5)

Stage IV. 11 1-0 14 | nee IV.

Mean, 0°96 mm. | 6 0-9 Mean, 1:0 mm.

Stage Ve 3) 0-7

Mean, 0°66 mm. | l 06

Taste A.—Total specimens measured: 65 2? + 36 ¢ =101.

It will be noted that the total numbers are very small in both sexes, but higher totals

are available in some other species.

Now, taking the mean lengths of the females at the different stages :—0°62156=

0:96; 0:96156=1:497 (mean 1°50); 15501'56=2°34,—that is to say, the mean

length of the shells at each stage when multiplied by (what we may call) the growth-

factor 1:56 * yields approximately the mean of the next oldest stage. The males are

much fewer and therefore respond less accurately: —1:01:45=1:4; 1:4 x 1:45=2°03.

In other words, at each of the growth-moults, the shells of the females increase by

some 56 per centum of their length, and those of the males by some 45 per centum.

The decimals would no doubt require alteration (especially in the males) if more

specimens were available; as already said, the case of imbricata is less conclusive

mathematically than zoologically. Even in species more plentifully available it is

hardly possible to get the second place of decimals in the observed mean to coincide

precisely with that in the mean calculated from the growth-factor; the reason being

that it is impossible to measure these little biconvex and delicate shells with any

pretence at accuracy to a hundredth of a millimetre, which is the second place of

decimals in this instance.

The observed lengths and their frequency have been plotted on scale-paper in the

accompanying diagram (fig. A, p. 226). The abscissa represents a millimetre-scale from

0°5 to 2°7 mm.; the ordinates on the left of this represent the observed numbers of

females, the ordinates on its right those of the males. Even with the small total

* Determined empirically on a slide-rule.

226 DR. G. H. FOWLER—BISCAYAN PLANKTON:

number available, the tendency of the ordinates to form a curve of frequency at each

stage is noticeable, though the shape and area of the curve is entirely guesswork in the

present instance *. When the numbers are greater, and a greater range of variation is

found in each curve, the extremes of the curve may respond to the same growth-factor

as the means. Even here, in the more numerous females, 0°6X1:50=0°9; 0:°9x1°56

=1:4; 1:4x1:56=271, that is to say, the shortest observed length at each stage multiplied

by the growth-factor gives the shortest at the next stage: and 0°7x156=1°0;

1:0 1:56=1-56 (1°6) ; 1:6 1:56=2'49 (2°5), that is to say, the same is approximately

true for the greatest length at each stage.

Literature.—a list of the most important memoirs was given in Professor Miiller’s

‘Valdivia’ Report. Two have appeared since that date: V. Vavra, ‘Die Ostracoden

der Plankton Expedition, 1906’; and C. Juday, “ Ostracoda of the San Diego Region,”

Univ. Calif. Public., Zool. vol. iii. no. 2, pp. 18-38 (1906), as well as Miiller’s own

Reports on the Ostracoda of the ‘ Siboga’ and ‘ Belgica’ expeditions.

* In this explanatory instance of imbricata alone, an imaginary curve of frequency has’ been drawn over the

ordinates. In subsequent diagrams of other species, the ends of the ordinates have been connected by dotted straight

lines, rather in order to show which of them can be grouped together as belonging to the same stage, than with

any mathematical meaning.

THE OSTRACODA, 2

II. SYSTEMATIC PART.

In Halocypridee, as in nearly every group of Crustacea, we owe the main lines of

morphological and taxonomic study to the late Professor Claus. With only a few

specimens of comparatively few species at his disposal, chiefly from material obtained

by Professor Chun at the Canary Islands, he produced in 1891 (after two pioneer papers)

the important monograph ‘ Die Halocypriden,’ which showed the variety and interest of

this family. Whether the wide systematic distinctions to which he called attention are

to be utilised to divide ‘‘ genera” (as Claus did) or ‘‘ groups” (which Dr. Miiller prefers),

does not seem to be very important. This monograph was accepted by all intermediate

writers till 1906, when Professor Miiller’s Report on the Ostracoda of the ‘ Valdivia’

Expedition appeared; this has added enormously to our systematic knowledge, and

will remain the standard for some time to come; the taxonomy and synonymy therein

laid down have been accepted in the present memoir.

The descriptions and figures in this part are intended merely to be supplementary to

those in Miiller’s ‘ Valdivia’ Report. Where they overlap, the object is to supply ready

material for comparison of the different stages of the same species.

Of these stages, that which is believed to be the oldest is termed Stage I., it being in

all cases, at present, uncertain at which morphological stage or length the larva is

hatched. As it is easiest to pass from the known to the unknown, the oldest stage

available has been made the starting-point in all descriptions.

Dr. Miiller’s synonymy and grouping have been adopted, except for the fact that some

of his species have been placed as stages in the life-history of species already known:

this suggested linking of “species” is shown in the following table :—

Previous Name.

IRE

Name of Species. Stage II. Stage I.

GURY 5° oR Leto et curta. stigmatica.

CapONOIde Mites Glos se. fe daphnoides, daphnoides,

var. minor var. major.

= lacerta.

hyalophivillumit sks} se hyalophyllum. lophura.

HOMICAT MEER eS se te loricata. etenophora.

PAP Oe ee 8s magna, macrocheira.

(ONCE a. en vot 1 ron procera. decipiens.

TRIER A a econ oe spinirostris. porrecta.

The mean length in mm. of each sex at each stage, when possible, is given thus.

(Mean, 0:00), and is based solely on my own observations. ‘To have included the lengths

given in previous records might have led to error, as taking for granted that the mean of

a stage is the same at every geographical position and sea-climate ; this is probably not

SECOND SERIES.—ZOOLOGY, VOL. X. 39

228 DR. G. H. FOWLER—BISCAYAN PLANKTON :

the case *. For example, Miller notes under many species that the Antarctic specimens

were larger on the whole than those from the tropical and temperate regions traversed

by the ‘ Valdivia.’ Again, not all observers measure the same “length”: Dr. Miiller

seems to have included the rostrum, and a spine when present.

For diagnostic characters I have followed Miiller’s admirable selection as far as

possible, except in the case of the shell-sculpture. In formalin specimens of most of the

species which I have seen, the sculpture is often so difficult to make out (as, indeed,

Dr. Miiller himself admits), that it can only be regarded as a secondary diagnostic

character at best. Of two specimens of the same length and the same species from the

same haul, it may be conspicuous in the one, nearly invisible in the other.

As regards the various glands, for the diagnostic value of which we are indebted to

Miiller, a little caution is necessary. They were by no means always so obvious in my

formalin material as they appear to have been in the ‘ Valdivia’ collections. Some

experiments in staining seemed to show that the obviousness of the glands when

unstained varied very much, and presumably depended upon their physiological

condition (secreting or discharged) at the moment of death.

If it is desired to stain formalin specimens for the glands, the following method will be found useful :—

To a (7 per cent.) store solution of formalin add 5 per cent. of Delafield’s hematoxylin ; the mixture

should be made fresh daily, and filtered. After immersion in this for about twenty minutes, the

apertures of the gland-cells will be found deeply stained, the cell-walls slightly stained ; the asymmetrical

glands assume a brownish-yellow tint.

As with other smaller members of the macroplankton (excepting Cfenophora), formalin is the best

reagent both for killing and storing. Mercury bichloride is detestable, rendering the tissues opaque and

unyielding, and covering the specimens with a dust of apparently insoluble mercuric compounds.

Alcohol leaves the specimens clean, but equally opaque and resistent. Picric acid did not seem to have

any special value.

HALOCYPRID&.

The species of Conchecia in this memoir have been arranged in alphabetical order for

convenience of reference. The following table shows their distribution according to the

groups recognized by Dr. Miller :—

Group of Species.

SpiMitera: = cu) we enn spinifera,

inermis.

ele gases ire sa) ues, Ce elegans.

PLOCELA Bac. =. <a; POE procera= decipiens.

brachyaskos.

* In this connection Conchecia would form an interesting test-case of the suggestion which has been put

forward, that polar, sub-polar, and deep-water forms—that is, cold-water forms—owing to a less rapid metabolism,

live longer, become sexual later, and grow larger, than forms of the same species in tropical waters,

THE OSTRACODA., 229

Group of Species.

NOUMING ALAM ys cl 4s as rotundata,

pusilla, var. major.

CUT wac Rircasre gc Wis ot: bs bi wr curta=stigmatica.

lOO, 4 6 6706 Sp eae 6 Haddoni.

LYS CEES VR: nr loricata=ctenophora.

WEEKS Ge ano CO ere magna=macrocheira.

hyalophyllum=lophura.

spinirostris = porrecta.

zeteslos, sp. 1.

TOOUISMMRee MP s,s kampta.

tyloda.

rhynchena.

TM DEICHLAMe nee se ss ee imbricata.

ametra.

daphwoides marm-nr ss daphnoides =lacerta.

Only four of Miiller’s fifteen groups were not represented, those of dentata, acuminata,

obtusata, and alata.

CoNCH@CIA AMETRA, Miiller.

(Plate 16, figs. 1-19.)

The sizes of this species were given by Miller (p.118) as: 9? 41-46, 3 3°7-41.

Measurement of his figure shows that he included the rostrum and posterior spine in

these lengths; this figure, measured in the manner adopted in the present memoir,

gives a length of 3:5 for the female ; his specimens were therefore at the same stage as

my longest specimen, as also apparently were those of Vavré and Juday. ‘There is

probably an older stage not yet captured, since the next lowest stage (mean 2°16) had

not developed secondary male sexual characters.

Stace IT.

Mate (Mean 3°10).—Shell elongate; the height about half the length; with a.

marked shoulder-ridge. The dorsal border of both shells terminates posteriorly in a

single spine, the left being longer than the right; the posterior border begins nearly at

_Tight angles to the dorsal border; the postero-ventral angle rounded off. The ventral

border is slightly arcuate, and does not begin to taper till well in front of the middle of

the length; the shell is about equally high in front of and behind the arcuation.

Rostra of the general type of the imbricata-group, but shorter than in imbricata ; they

are asymmetrical, the left being longer than the right. A papilla which carries the

openings of the glands of the right side is large, and projects markedly beyond the shell-

outline; that of the left side is small, and projects little or not at all. Sculpture of the

shell strongly marked, agreeing with that of ametra. Frontal organ with only a

small part of the stem projecting beyond the antenna. Terminal joint proximally much

39*

230 DR. G. H. FOWLER— BISCAYAN PLANKTON:

thicker than the stem; diminishing towards the apex, constricted and bent upwards

before the middle of its length; carrying five or six long spines on its dorsal border,

numerous short spines on the proximal two-thirds of its ventral border. Antenna i.:

the principal bristle carries about 83 pairs of foliate appendages (as in ametra), back-

wardly directed, diverging widely when both rows are seen from above them; in front

of them are three or four short upright spines. A small pad (Schiele) occurs on the

proximal accessory bristle ; hairs of the terminal bristles, if present, exceedingly minute.

Antenna ii. with two central bristles on the inner limb, the one about two-thirds of

the length of the other: the basal bristles more widely apart than usual, the one very

long and slender, the other short and leaf-like. Hook-joint of the right side very strong,

curved at first through about 90°, then curved through a widely obtuse angle; slightly

thickened terminally, ending in a spike; a tooth on the proximal part. Hook-joint of

the left side long, bent through 90°, ending in a spike.

Frma.e (Mean, 3°30).—Shell elongate, of more triangular outline than in the male,

because beginning to taper further back. Shoulder-ridge less marked, postero-ventral

angle more sharply rounded than in the male. Postero-dorsal spines and rostrum as in

the male. Ventral border arcuate; the greatest height behind the arcuation, thence

tapering sharply forward. Frontal organ: the stem projects for some distance

beyond the first antenna. Terminal joint nearly completely segmented from the stem,

tapering slightly, depressed above, but not bent so much upwards as in the male.

Spines more numerous on the dorsal border than in the male, extending over more than

the proximal half. Antenna i. with a long dorsal bristle. Antenna ii. with two

hairless central bristles, the one about two-thirds the length of the other, and with a

long and a short basal bristle. The terminal bristles and tubes more or less beset with

fine spines proximally: the longest but one with fine spines nearly throughout its length ;

the longest slightly lanceolate.

Stace II.

Mate (Mean, 2°16).—Shell much as in Stage II. (the right shell of fig. 8 has a

slightly more triangular appearance than the left of fig. 3, owing to the projecting

gland-papilla). Frontal organ unsegmented, spineless, the terminal part not much

thicker than the stem, ending in a blunt point. Antenna i. with the principal bristle

of female character *, Antenna ii. as in Stage IV.

Femate (Mean, 2°3).—Shell much as in Stage II. but rather less markedly tri-

angular. Frontal organ unsegmented, spineless, much as in the male of the same

stage. Antenna i. with a short dorsal bristle (not shown in fig. 16). Antenna ii. as

in Stage II.

Stace LV.

Matze—A much broken specimen of g1:6 mm. was apparently referable to this:

the frontal organ and inner branch of antenna ii. have been figured.

* This carried a straight dorsal bristle in one specimen, presumably as an abnormality; the same was occasionally

noted in males of other species.

THE OSTRACODA. 931

Frmate (Mean 1:42).—Shell much less triangular than in the later stages, owing to

the ventral border being now slightly convex instead of arcuate. Spines, papillee, and

rostra as before, but rather shorter. Frontal organ still very long, unsegmented,

terminal part only slightly thicker than the stem ; ending bluntly, spineless. Antenna i.

without dorsal bristle. Antenna ii. with central bristles as in Stage III.; no basal

bristles.

CoONCH@CIA BRACHYASKOS, Miller.

(Plate 16. figs. 20-29.)

The specimens were unfortunately too few to allow of the successive stages being

determined mathematically; but at least two male stages, and possibly three female

stages, were recognizable: figures are given to help future observers. The shell of the

only male of 0°9 mm. was unfortunately damaged before being drawn; it appeared,

however, closely to resemble the larger specimens.

In addition to Miiller’s description (p. 70) it may be noted that the older shells

generally carried a small spine, like that of procera. In the female, the frontal organ

was generally curved downwards more than in Miiller’s figures (xiv. 7,8). In the male,

the teeth of the armature of the principal bristle of the first antenna (fig. 21) seemed

rather more curved than in his drawing (xiv. 14). There were fifteen pairs of these

teeth more or less opposite to one another, followed by four single teeth proximally.

These differences were presumably within the limits of individual variation.

Concnecra curtTA, Lubbock.

=C. stigmatica, Miller.

(Plate 17. figs. 30-54.)

The special difficulties presented by the shape and size of this species, which tend to

obscure the successive stages, are mentioned in detail on pp. 259, 260. In the male,

Stages I. and II. (the stages with secondary sexual characters) are pretty clear ; the earlier

stages are guesswork. In the female, the successive stages are little differentiated

morphologically and are by no means clear. I should not have dared to associate

stigmatica with the oldest stage of curta if the necessary confirmation by analogy had not

been available from larger species, in which one is on more certain ground ; but a careful

comparison of the figures with the similar succession in other forms will, I think, leave

no doubt of the correctness of the determination. The only point in which the succession

differs from that observed in the other species lies in the reduction of the number of

“teeth” on the principal bristle of antenna i. in the male; they are, however, quite

rudimentary and inefficient, as compared with other species, at the previous “ curta

stage;” this being so, their further reduction at the ‘‘ stigmatica stage” would seem to

suggest that they are being abandoned.

It may be said that I have included two separate species under cwrta, and it is certainly

possible; but the possibility has been steadily borne in mind, and I have found myself

unable to split the species. Unfortunately the measurements of the older specimens

are too few to give any clue, and are themselves somewhat chaotic. A large series of

older specimens is needed to set the species on a proper footing.

232 DR. G. H. FOWLER—BISCAYAN PLANKTON:

The position of the opening of the right asymmetrical gland seems to be different in

the various figures; this is mainly due to a dorsal or ventral tilting of the biconvex

specimens: its real position appeared to be at or just below half the height, except in

the very youngest specimens, where it is apparently higher.

Stace I. (stigmatica stage).

Mate (about 1 mm.).—Shell with the shoulder-ridge very strongly marked*. The

posterior border begins as a nearly straight line making an obtuse angle with the dorsal

border; at the opening of the right asymmetrical gland it becomes a steady convex

curve, which passes on without postero-ventral angle into the convex ventral border, and

then turns up rapidly as a flattened curve towards the rostrum. Frontal organ much

thicker than the stem, sometimes more flexed downwards than in fig. 31: thickest

proximally, gradually tapered by depression of its dorsal border, the ventral border

being nearly straight; ending bluntly, spineless. Antenna i.: the principal bristle

carries 5-8 minute warts, very difficult to see. Antenna ii.: the right hook begins

with a very broad base; becoming thinner, it commences to bend round with no trace

of an angle, is thicker at the highest point of the bend, and then tapers with a slight

S-curve, terminating in two divergent spines. The left hook, beginning with a thick

base, shows a distinct angle, and then tapers gradually like the right hook. One

proximal sense-tube is thickened at its base, and either dentate or spined. There are

two subequal basal bristles; of the central bristles, the one is about twice the length of

the other ; all are hairless. (One of each was obscured by its fellow in fig. 33; compare

fig. 37.)

FremAte (about 0°95 mm).—Shell: the posterior border begins to curve almost imme-

diately after the postero-dorsal angle, and the curve is continued steadily till just below

the rostrum; the antero-ventral border being more sharply curved and less flattened,

the female shell has a more rounded and less pointed outline than in the male.

Frontal organ showing a good deal of variation; always imperfectly segmented,

bluntly rounded or truncated, spineless, straight or very slightly bent. Antenna i.

with the distalmost sense-tube bifid, one branch being very short (fig. 47). Antenna ii.

with two central bristles, the one about twice as long as the other, both hairless. No

basal bristles.

Srace II. (curta stage).

Matz (about 0°76 mm.).—Shell much as in Stage I., but a little higher for its

length. Frontal organ strongly flexed downwards, slightly curved, thickest distally,

terminating bluntly, spineless. Antenna i. with an armature of 9-127 blunt

points on the principal bristle. Antenna ii.: the right hook much as in Stage I., but

with a thinner base; the left hook without an angle. One sense-tube is thickened at

its base, which is dentate or spined.

FEMALE (about 0°7 mm.).—Shell much as in Stage I. Frontal organ of the type

* This is so at every stage observed, and will not be repeated.

+ Miller records 8-13, but I have not observed so great a range.

THE OSTRACODA, 233

described and figured (xxx. 3) by Miiller; it was not observed to show so much variation

as at Stage I.; this may be accidental, as a good deal was observed at ? Stage III. below

(0°5 mm.). Antenna ii. as in Stage I.

EARLIER STAGES.

MALte (about 0°5 mm.).—Shell markedly resembling that of the female at the same

length; posterior border rather straight; a steady curve from the gland-opening to

just below the rostrum, not flattened antero-ventrally. Frontal organ unsegmented,

nearly straight, sometimes tapered, ending bluntly. Antenna i. with principal bristle

of female character. Antenna ii. carries one basal bristle (? two), and two central

bristles as before.

Femate (about 0°5 mm.).—Shell higher for its length than in the later stages,

posterior border nearly straight, followed by a strong arching of the ventral border.

Frontal organ exhibiting similar variation to Stage I.; the commonest type is shown

in fig. 51. Antenna ii. as in later stages.

Figures are also given of (? 2?) shells at 0°45 and 0°39 mm., which may perhaps

illustrate earlier stages.

CONCHGCIA DAPHNOIDES, Claus.

(Plate 17. figs. 55-57.)

Both males and females at Stage I. were fairly numerous. I have no doubt that what

has been described as lacerta, Brady & Norman, and daphnoides, var. minor, Miiller,

form Stage IT. of this species *, but it was not taken by the ‘ Research’ on this occasion.

A single specimen of Stage III. was, however, captured.

In supplement to Miiller’s description, it may be noted that in the male nine reversed

teeth were counted at the distal end of the armature of the principal bristle, and that the

proximal bristle carried a few fairly stout teeth. In the female, the inner branch of

antenna ii. resembled Miiller’s figure of the male (xxxi. 13), except, of course, for the

absence of the hook, and sometimes carried one basal bristle; the three sense-tubes were

spined proximally, the two bristles distally.

The shells and frontal organ of Stage III. are figured. In antenna ii. the central

bristles were as in Stage I., but hairless; there was no basal bristle; the terminal

bristles and tubes were spineless.

CoNCH@CIA ELEGANS, Sars.

(Plates 17, 18. figs. 58-73.)

Srace IT.

Mate (Mean, +1°'1).—Shell without marked shoulder-ridge (unlike spinirostris) ;

generally with two sharp spines on the postero-dorsal angle of the right shell; below

the spines the posterior border is concave for a short distance, then convex. The

opening of the right asymmetrical gland does not project as in procera; it lies at the

postero-ventral angle of the shell, not far forward as in procera; the angle is well-

marked as the meeting-point of the posterior and ventral borders, unlike spinifera.

* Compare p. 263 note.

234 DR. G. H. FOWLER—BISCAYAN PLANKTON:

Ventral border convex; the shell is highest about the middle of the length. Frontal

organ very short, of the form drawn by Miller (xiii. 20) or as in figure 59. Antenne

i. and ii. as drawn or described by Miller (xiii. 21, 22, 26).

Ferma ze (Mean, +1:12).—Shell of the same character as in the male, except that

on the posterior border the upper part is generally more deeply concave, the lower more

sharply convex. The ventral border somewhat more tapered than in the male.

Frontal organ and Antenna i. as drawn by Miller (xiii.* 10, 11, 24), the former

projecting only a short distance beyond the latter (unlike spinifera and procera).

Antenna ii. without basal bristles, with two short hairless central bristles, the one

about twice the Jength of the other.

The extent of the concavity of the posterior border is more or less impressive,

according as the spines are more or less developed ; but the convexity is always greater

in the female than in the male.

Srace ILI.

Mate (Mean, +0'9).—Shell much as in Stage II., but slightly more tapered an-

teriorly +. Frontal organ unsegmented, the terminal part swollen, ending bluntly.

Antenna i. with the principal bristle of female character. Antenna ii. as in the female,

except for the presence of a single basal bristle.

Frmae (Mean, +0°86).—Shell with the posterior border as in Stage I., but the

ventral border is more convex, and the shell therefore higher in proportion to the length.

Frontal organ very larval in character, only slightly swollen terminally. Antenna ii.

as in Stage IT.

It is very difficult to distinguish these young specimens at first from Stage III. of

spinifera. But the frontal organ, which in elegans only just projects beyond antenna i.

extends in spinifera a long way beyond it. Further, spinifera has a well-marked

shoulder-ridge; and was not observed at this stage to carry a spine, whereas elegans

generally does. The ventral border is more convex in elegans, straighter in spinifera.

The characteristic openings of the marginal glands in elegans, figured for Stage I. by

Miiller (xiii. 19), are very imperfectly developed at this and earlier stages.

Srace LV.

Shells (¢ 2 Mean, +0°6) of both male and female as in their respective sexes at

Stage IIL, except that the ventral border is more convex, and the shell is fuller in

front, so that the highest point lies a little in front of the middle of the length. No

postero-dorsal spine was observed at this stage. The male was distinguishable from

the female only by the rudiments of the penis. Cephalic organs as in Stage III.

female.

* Figure 29, between figs. 21 and 25 on.this plate, should apparently be 28, and of a male.

+ The specimen drawn in fig. 60 had the spines rather better developed than that of fig. 58; hence at first the

postero-dorsal coneayity appears to be more strongly marked.

THE OSTRACODA, 235

Stace V.

Femate.—Shell with nearly straight posterior border and deeply convex ventral

border. Cephalic organs as in Stage II. female, except that there was only one

central bristle on antenna ii.

CONCH@CIA HADDONI, Brady & Norman.

(Plates 18, 19. figs. 73-89.)

Miiller expresses the opinion (p. 90) that a larger southern race (2 2°6—2°95,

dg 2°2—2'5)* can be distinguished from a smaller northern race (2 only up to 2°6, ¢ to 1:9),

but he recognises that this idea is opposed to the fact that Brady’s specimens from

53° N. (coast of Ireland) belonged to the larger race. He regards a re-investigation of

the specimens as urgently needed for the certain identification of the species. My

specimens of Stage I. are also large (up to 3 mm.), and leave absolutely no doubt of

their identity with the species of Miller and of Brady and Norman; it is enough to say

that they agree point for point, and it is unnecessary to re-describe and re-figure every

detail. The collection is short of males, but the extreme sizes which he gives for females

(2'2-2°95) are well within the limits of size-variation of the older stages of a large

adult.

Srace [.

FEMALE (Mean, 2°72).—Shell with the posterior border slightly concave above,

convex below ; no recognisable postero-ventral angle; the opening of the right asym-

metrical gland is on the posterior border at about one-third of the height; it is not

prominent at any stage of either sex; the shell is highest behind the centre of the

length. In Dr. Miiller’s figure (xviii. 1) the shell is apparently much higher posteriorly

than in my figure 78, but the rostrum shows that the specimen had fallen slightly

forward ; my specimens present a similar outline when in the same position. Frontal

organ and Antenna i. as figured by Miiller (xviii. 3, 4,8). Antennaii.: the long

basal bristle may carry a few short hairs; there is also a small bunch of hairs, difficult

to find, on the joint just proximal of this bristle.

Mate (2'1 mm.).—Shell with the posterior border slightly concave above, but the

convex curve protrudes less behind a perpendicular from the postero-dorsal angle than

in the female; the ventral border is convex; the highest point at about the middle of

the length. Frontal organ and Antenna i. as drawn by Miiller (xviii. 6, 7).

Antenna 1i. with one unusually long basal bristle, and one very short ; of the central

bristles, the one is about two-thirds of the length of the other, both are long and with

fine short: hairs. Some of the terminal bristles and tubes with hairs, as in the

female.

Stace IT.

FEMALE (Mean, 1:66).—Shell with the posterior border as in Stage I.; the ventral

border convex, so that the greatest height is now about the middle of the iength.

* His figure of a female measures 2'8 without the rostrum.

SECOND SERIES,— ZOOLOGY, VOL. X. 40

236 DR. G. H. FOWLER—BISCAYAN PLANKTON:

Frontal organ unsegmented, spineless, swollen anteriorly. Antenna ii. retaining

the long basal bristle; the hairs on the terminal bristles and tubes few or absent.

Mate (Mean, ? +1°45).—This stage was not observed.

2 = 'S)

Stace ITT.

Fremae (Mean, 1:01).—Shell with the posterior border not projecting so far pos-

teriorly as in the later stages; the ventral border is more sharply convex; the height

more than half the length. Frontal organ fairly long, blunt, spineless, somewhat

swollen anteriorly. Antenna ii. with a short basal bristle, difficult to see in most

positions. No hairs on the terminal bristles or tubes.

Matz (1:0 mm.).—Shell with the posterior border as in Stage I., but the height rather

greater in proportion to the length. Frontal organ as in the female of this stage,

but rather shorter. Antenna i. with the principal bristle of female character.

Antenna ii. much as in the female. No hairs on any of the bristles.

Stace LV.

FrmaLe (Mean, 0°66).—Shell more sharply convex ventrally than in Stage III.

Antenna ii. with no basal bristles and only one long central bristle.

Mate.—tThis stage was not observed.

In Stages ITI. and IV. the large gland-cells described and figured by Miiller (xviii. 2)

were sometimes very conspicuous.

Srace V.

Femate (of 0°4 mm.).—The high position of the opening of the right asymmetrical

gland seems to indicate that this was attributable to haddon?. Shell with the height

about five-sevenths of the length, very sharply convex ventrally. Frontal organ much

as in Stage IV. Antenna ii. as in Stage IV.

Matz of this stage not observed.

CoNCH@CIA HYALOPHYLLUM, Claus.

= C. lophura, Miiller.

(Plates 19, 20. figs. 90-109.)

Stace I. (/ophura stage).

FEMALE (Mean, +2°3).—Sheil with the posterior border forming a flattened curve;

no marked postero-ventral angle; the ventral border slightly arcuate, and the shell

higher behind the arcuation than in front. Lateral glands well-marked ; a collection of

long cells on the ventral border of the left shell behind the arcuation was less pronounced

than in Miiller’s figure of lophura (xx. 2), but clearly recognisable. Frontal organ

incompletely segmented; the terminal joint gradually enlarging distally, then abruptly

constricted ventrally to form a sharp, downwardly directed spine. ‘There are numerous

fine spines on the dorsal border, and stout spines on the ventral border; the whole

structure closely resembling that figured by Miiller for lophura (xx. 10). Antenna i.

with a Jong dorsal bristle carrying fine hairs. Antenna ii. with two central bristles ;

THE OSTRACODA. 937

the longer, which carries stout short hairs, is nearly twice the length of the shorter,

which carries comparatively few fine hairs.

Only one well-preserved specimen was observed, with a length of 2°5 mm. (34/,

750-500 fm.). A poorly preserved specimen of 2°1 mm. may also be referable to this

species (23a, 1000-750 fm.).

Mater (Mean, +2:1).—Shell elongate, with a well-marked shoulder-ridge. Posterior

border nearly straight, and nearly at right angles to the dorsal border ; postero-ventral

angle not marked ; ventral border slightly arcuate, the shell about as high in front of

the arcuation as behind it. Lateral glands conspicuous, and there is a collection of

long gland-cells on the ventral border of the left shell behind the arcuation (compare

Miller's figure xx. 2). Frontal organ with the terminal joint very thick proximally,

constricted about the middle of its length, expanding again to a rounded end.

Antenna i. with an armature showing about 66 teeth in profile view (it was not possible

to make out how many of these 66 were in pairs); the teeth are very small, closely set,

and as figured by Miiller (xx. 4), except that they appeared to be more sharply pointed.

Antenna ii. as drawn by Miiller (xx. 7, 9): there is one long fine basal bristle with

fine hairs, and one very short bristle; the longer of the two central bristles carries

short stout hairs distally as well as the long setze proximally.

A single specimen, 2°3 mm. in length, was taken in the non-comparable haul 36 /

(850-0 fim.).

Stace II. (hyalophyllum stage).

FEMALE (Mean, 1:58).—Shell markedly resembling that of magna at Stage LI., but

the posterior border is more sharply rounded, and on the ventral border the shell is

slightly higher behind than in front of the arcuation; consequently the shell tapers

more anteriorly. Frontal organ and Antenna i. as drawn by Miiller (xx. 23, 24):

the terminal joint of the frontal organ has the dorsal and ventral borders less parallel

than in magna; it swells gradually from the base towards the tip (not suddenly as in

parvidentata) ; at the tip it is suddenly reduced toa sharp spine. The small spines on

the organ are more numerous than in magna, and are more concentrated anteriorly and

ventrally. The dorsal bristle of antenna i. carries numerous very fine hairs ; in pro-

portion to the diameter of the bristle they are larger than magna Stage II., but are

almost equally difficult to see. Antenna ii. with the bristles much as in magna.

Matz (Mean, 1°50).—Shell much as in magna Stage IL., but less arcuate and with

somewhat stronger shoulder-ridge. Ventral border very slightly arcuate, rising an-

teriorly sooner than in magna; shell about as high in front of the arcuation as behind

it. The lateral glands are often very difficult to see, both in male and female; one

seldom finds more indication of them than the three little points shown in fig. 97.

Frontal organ with the terminal joint curved as in magna, but not so much constricted

in the middle (fig. 94); both ends nearly of the same thickness. Antenna i.: the

principal flagellum is a little longer than the two secondary flagella. The armature is

very difficult to make out, the teeth being, as a rule, hardly longer than those on the

principal flagellum of the female in many species. It appears to consist of about 22

40*

2355 DR. G. H. FOWLER—BISCAYAN PLANKTON:

pairs of minute teeth, set at about their own length from one another, followed

proximally by 15-20 pairs of similar teeth which are spaced more widely apart.

Antenna ii. as drawn by Miller (xx. 20, 21): but the long hairs of the longer central

bristle are often missing (? dropped off); the shorter bristle may carry a few short hairs.

Of the basal bristles, the one is rather longer than the other (the foreshortening in

camera drawings is apt to mislead).

Stace ITT.

FremaLe (Mean, 1:07)—Shell practically indistinguishable from that of magna

Stage III., except for the lateral glands. Frontal organ of the same general type as

in Stage I., but less swollen, unsegmented, projecting far beyond the antenna.

Antenna i. with a hairless dorsal bristle. Antenna ii. with the central bristles as in

Stage I., but smaller. No basal bristles.

Mate (Mean, 1:08)—Shell practically indistinguishable from that of magna

Stage III., except for the lateral glands. Frontal organ resembling that of the female

Stage I., except that it shows no segmentation, and carries fewer and shorter spines.

Antenna i. with the three flagella clearly differentiated, the secondary a little more

than half the length of the principal. Armature of female character. Antenna ii.

without hooks; the central bristles as in female Stage I., but smaller. No basal

bristles.

Stace IV.

Mate (Mean, 0°7).—Shell as in Stage I1., but slightly higher in front of the arcuation

than behind it. Frontal organ swollen terminally, unsegmented, still bearing a

terminal spike.

Fremauz of this stage not observed.

CoNCH@CcTA IMBRICATA (Brady pars), Miiller.

(Plate 20, figs. 110-121.)

Four stages were recognised in this species, of which only the oldest showed secondary

sexual characters in the male. From the analogy of other forms, I have no doubt that

a yet larger stage exists, and is to be found in deep water.

Miiller records (p. 118) the lengths of 3:0 to 3:5 for females, 2°5 to 3-0 for males.

Measurements of his figure (xxviii. 1) show that he included rostrum and posterior spine

in the “length,” and that his specimens corresponded to my Stage II., with means

of 2°34 9,201 o.

Stace IT.

Frmate (Mean, 2°84).—Shell agreeing with that described and figured by Miller

(xxxvili. 1), Frontal organ sometimes rather more curved than in Miiller’s xxxviii.

fig. 8, beset thickly with stout spines on the proximal fifth of its dorsal border and

proximal half of its ventral border. Antennai. with hairless dorsal bristle. Antenna iL:

THE OSTRACODA. 239

the one central bristle about two-thirds of the length of the other. No basal bristles.

Two of the sense-tubes carry proximally sharp teeth.

Mate (Mean, 2°01).—Shell much as in the female of the same stage. Antenna i.:

the principal flagellum carries 17-20 teeth in all, which in profile look like 8-10 pairs,

but proximally are not quite symmetrical. There are a few fine spines on the accessory

flagellum opposite the distal end of this row of teeth. Antenna ii. with two central

bristles, one rather longer than the other; and a small basal bristle.

Stace III.

Frmaxe (Mean, 1:50).—Shell much as in Stage II. Frontal organ long, straight,

unsegmented, the future terminal joint rather thicker than the stem. Antenna i.

with hairless dorsal bristle. Antenna ii. with central bristles as in Stage II. ; at least

one sense-tube with a few proximal teeth.

Mate (Mean, 1°48).—Shell much as in female of the same stage. Frontal organ

and Antenna i. resembling those of the female at the same stage except for the absence

of a dorsal bristle. Antenna ii. with central bristles as in the female, with the addition

of one basal bristle. No hook-joint as yet developed.

Stace LV.

Frma.e (Mean, 0°96).—Shel1 shorter for its height than in the later Stages 11.-IIT.;

squarer and less triangular in outline; the highest point of the shell is now about the

middle of the length instead of being behind it. Rostrum proportionately shorter.

Frontal organ simple, straight, unconstricted, nearly equally thick throughout its

length, slightly pointed. Antenna i. without dorsal bristle. Antenna ii.: longer

central bristle about twice the shorter one; no teeth on sense-tubes.

Mate (Mean, 1'0) agrees with the female of the same length in all the points just

mentioned ; distinguishable by the presence of the penis.

Stace V.

Ferma (Mean, 0°66).—Shell still shorter for its height, and rostrum shorter. The

postero-dorsal spines nearly of the same length; the postero-ventral prominences

persist.

Matz of this stage not observed.

CoNCH@CIA INERMIS, Claus.

(Plate 20. figs. 122-126.)

Only three specimens were observed, ¢ 1°5,1°9, 2 2:0. Of these the two longer

agreed with Miiller’s description; the third was a male without secondary sexual

characters.

Stace ? II.

Mats (1°9).—Shell very long, the height is to the length about as 1 is to 2°7.

Shoulder-ridge fairly marked, postero-dorsal angle rounded off, posterior border nearly

straight and nearly at right angles to the dorsal border; tlhe opening of the right asym-

24.0 DR. G. H. FOWLER—BISCAYAN PLANKTON:

metrical gland is at the marked postero-ventral angle and is rather prominent. Ventral

border a steady convex curve, rather flattened ; rostrum of the long flattened type of the

imbricata and daphnoides groups. ‘The asymmetrical glands are in the usual position:

on the anterior border are numerous long gland-cells which do not appear to meet in a

common opening ; they are particularly noticeable on the right shell. Frontal organ

strongly flexed ventrally, blunt, spineless. Antennai.: the principal bristle carries

very numerous, long, fine spines as in the daphnoides group; the two rows are widely

apart and the spines very divergent, directed proximally ; they are succeeded distally by

five or six short distally directed spines. The proximal accessory bristle carries about

10-15 pairs of very small spines, regularly set in pairs, on a level with the distal end of

the armature of the principal bristle. Antenna ii. as described and figured by Miiller

(ix. 27); the two basal bristles short, nearly equal in length.

FrmMALe (2°0 mm.).—Shell very elongate; the height is to the length about as

1: 2°55 it is of the same general contour as in the male *. Frontal organas described

and figured by Miller (x. 6). Antenna ii. with two central bristles, the shorter about

three-quarters of the longer: both hairless.

Stace ? IIT.

Matz (1'5 mm.).—Shell rather fuller in front or less tapered than in Stage P TI.; the

height is to the length about as 1: 2°6. Otherwise much as in Stage ?IT. Frontal

organ straight, constricted between the stem and the future terminal joint, but not

completely segmented; terminal part swollen, ending in a blunt point directed slightly

downwards. Antenna i. with principal bristle of female character. Antenna ii. with

one basal bristle ; two central bristles as in Stage P II.; no hook-joint.

ConcH@crA KAMPTA, Miiller.

Two males, one of 2°5 mm., the other with broken shells, carried unmistakably the

characters of the first and second antennee of this species. There were about 48 pairs of

leafiets on the principal bristles, and the distal accessory bristle carried about 19 strong

teeth (not pairs). The stage would seem to be the same as that described by Miiller.

CoNCH@CIA LORICATA, Claus.

= loricata, var. typica, Miller.

= ctenophora, Miller.

(Plates 20, 21. figs. 127-138.)

A number of specimens were obviously referable to some member of the loricata

group, which includes only loricata, var. typica and var. minor, ctenophora, and (perhaps)

serrulata. So far as the‘ Research’ specimens were concerned, serrulata was out of the

question by reason of the shell-form.

The points in which var. minor and ctenophora differ from var. ¢ypica are given very

* Miiller states that his specimens were “ meist stark deformiert, zum Theil auf mikroskopische Priiparate”: this

accounts for his drawing of the female (xi. 25).

THE OSTRACODA, 241

briefly by Miiller; they are: (1) the extent to which the shell-sculpture is recognisable,

(2) the number and arrangement of the teeth on the principal bristle of antenna i., and

(3) the size of the shell. The first of these three points seems to be quite unreliable for

diagnosis in formalin specimens: of two otherwise absolutely similar specimens from the

same haul, the one would show well-marked sculpture, in the other it would be barely

visible ; this was noticeable in other species also. The other two diagnostic points might

be (and in the case of the two larger “ species” they probably are) merely expressions of

different ages or stages of the same species. Miiller furnishes the following particulars :—

Teeth. Size.

| loricata, var. minor .......0.0., +12 @ 1:6-1-7, g 1:5*.

ia SP LUDICAD | Waeccterets oie 2 + 22 Q@ 1:8-2:0, g 1:7-1-97.

CLEMO NNOT mete rto tte Role tots oaie teres in + 30 © 2:4-2:6, g 2°3-2°6.

$$ \

By size and by number of teeth my specimens were cfenophora; in every other

respect they agreed with Miiller’s description of loricata, var. typica. If, as I believe,

these are merely the last two stages of one species, the older name Joricata claims

priority.

Stage I. (ctenophora stage).

Mate (Mean, 2°31).—Shell more tapered anteriorly, and with a more marked

shoulder-ridge than in magna, posterior border nearly straight and at right angles to the

dorsal border, postero-ventral asymmetrical gland prominent, ventral border arcuate;

the shell not so high in front of the arcuation as behind it, the anterior border beginning

to taper upwards immediately after the arcuation. Frontal organ much as in magna,

about as thick after the central constriction as before. Antennai.: the toothed and

proximal toothless parts of the principal bristle subequal, the distal toothless part longer.

Teeth about 30-82 pairs, nearly all equal and nearly equidistant at all points. The

principal somewhat longer than the accessory bristles, which carry a few minute teeth.

Antenna ii. with the inner branch as drawn by Miiller (xxii. 17), but the longer central

bristle is often (not always) hairless, and the larger basal bristle is longer and slenderer

than (owing to foreshortening) appears in this figure. The process on the inner side of

the proximal part of the hook appears to be constant, and not to occur in magna.

Frmate (Mean, 2°58).—Shell with fairly marked shoulder-ridge. Posterior border

beginning above with a slight concavity, then markedly convex, projecting further

posteriorly than inthe male. Ventral border fuller than in the male behind the arcuation,

so that the highest point of the shell lies well behind the middle of the length. Other-

wise as in the male. Frontal organ and Antenna i. as drawn by Miller (xxii. 3).

* Figure without rostrum, 1-4.

+ Figure without rostrum, 1-7,

242 DR. G. H. FOWLER—BISCAYAN PLANKTON :

Antenna ii. with slender central bristles, the one nearly twice the length of the other ;

hairs, if present, extremely minute. No basal bristles.

In both sexes and notably in the female the lateral glands are often difficult to see:

the gland of the left shell is often more easily detected with a low power than its opening

with a high power. In many specimens the anterior ventral part of the shell is extra-

ordinarily glandular.

Stace IT. (loricata stage).

Mate (Mean, 1°75).—Shell much as in Stage I.; intermediate between that figured

by Miiller (xxii. 12) for loricata, var. minor, and that which he gives for loricata, var.

typica (xxii. 1), in that the posterior border is more nearly perpendicular to the dorsal

border than in the typical form; but the ventral border is more tapered, with the highest

point behind the middie of the shell, as in the smaller variety. The lateral glands are

in the usual position for the species. Frontal organ as figured by Miller (xxii. 4).

Antenna i, with about 22 pairs of teeth, the paired arrangement is practically carried

out to the proximal end of the rows, unlike the markedly alternating condition noticeable

in magna at this stage. The distal accessory bristle carried about 13 fine teeth; the

proximal had also a few, which were difficult to see. Antenna ii. as drawn by Miiller

(xxii. 6, 7), except that the hairs on the longer central bristle were not quite so long in

my specimens.

FemateE (Mean, 2°0)—Shell much as in Stage I.; the lateral glands present, but

difficult to see ; the posterior border not so prominent as in Stage I. Cephalic organs

as described and figured by Miller (xxii. 3), except that fine hairs occurred on more than

one terminal bristle.

Srace ITT.

Mate (1°4).—Shell more tapered antero-ventrally than in later stages, and therefore

more resembling their female type ; the lateral glands clearly visible. Frontal organ

long, unsegmented; the terminal part slightly thicker than the stem, the end bent

strongly downwards to a blunt spike. Antennai. with principal bristle of female

character. Antenna ii. with one basal and two central bristles, all hairless.

FrmMane (Mean, 1°3).—Shell very much as in Stage II.; lateral gland visible.

Frontal organ unsegmented; the terminal part thicker than the stem ; its blunt spike

not so much bent downwards as in the male at this stage. Antenna i. without a dorsal

bristle. Antenna ii. as in the male of this stage, but without a basal bristle.

CoNCHG&CIA MAGNA, Claus.

= macrocheira, Miller.

(Plates 21, 22. figs. 139-160.)

This was the most plentiful of the larger forms in the collection, and was apparently

represented by five stages. But it was hard to settle under what name it should go,

owing to the difficulty of deciding whether the penultimate stage belonged to subarcuata,

Claus, or to magna, Claus; these two names are of the same date. ‘The original source

=—"

THE OSTRACODA. 243

of the difficulty may lie in Claus having had both ultimate and penultimate stages

before him *.

The differences which Miiller in his text points out between these species are two :—

(1) Differences in the armature of the principal bristle of antenna i.; in my specimens

the proximal teeth are displaced, generally less so than in his figure of magna (xxi. 26),

more so than in his description of swbarcuata. They are spaced as in his figure of swb-

arcuata (xxi. 12) and not shaped quite like those of magna (xxi. 26). Claus assigns

about 20 pairs of teeth to magna, set more closely and more regularly distally than

proximally 7; this agrees with my specimens; but to swbarcuata he attributes 30 pairs.

(2) Differences in the hook of the inner branch of antenna ii. The right hook in my

specimens agrees better with magna than with swbarcuata in being bent at first sharply

through a right angle, and then curved boldly through a second right angle; on the

other hand, it is said by both Miller and Claus that in swbarcuata it is bent at first

through an acute angle {. (3) In Claus’s figures, the posterior border of the male shell

of subarcuata (ili. 3) begins with a concave curve, and projects much further than that

of magna (iii. 1). My shells agree best with magna.

On the whole it seems that the penultimate stage of the ‘ Research’ specimens must

be assigned to magna, Claus, leaving open the question whether the swbarcuata of Claus

and Miiller is founded on individual variation of magna, or is a separate species.

Stace I. (macrocheira stage).

FremMate (Mean, 3'°36).—Shell very oblong; shoulder-ridge slight; postero-dorsal

angle slightly rounded, posterior border a steady curve; right asynimetrical gland

slightly projecting; ventral border arcuate, the shell about as high in front of the

arcuation as behind it ; anterior border bluff, rounded. Frontal organ and Antennai.

as drawn by Miiller (xxi. 5, 6), with the addition of a bunch of short spines on the

terminal joint of antenna i. at the base of the principal bristle. Dorsal bristle with long

hairs. Antenna ii. with its inner branch as drawn by Miiller (xxi. 8). No basal

bristles.

Mats (Mean, 2°91).—Shell of the same general outline as in the female, except for

(1) a more marked shoulder-ridge, (2) astraighter posterior border, (8) a more forwardly

projecting rostrum. Frontal organ as drawn by Miller (xxi. 7). Antennai.: the

armature covers a little less thana third of the length of the principal bristle ; it amounts

to about 29-31 pairs of teeth; the order in pairs is retained throughout the row; the

first few and last few are shorter and closer together than the rest. Accessory bristles

* Tt is even possible that magna and subarcuata are one species, allowing for individual variation.

+ The displacement of the teeth from a regularly paired row into an alternating series is often difficult to deal

with, since a very slight twist of the axis of the bristle serves to produce this effect: in two antennw of the same

specimen, the teeth may appear at first to be greatly displaced proximally in the one, hardly at all in the other.

Further, unless the teeth are in exact profile, refraction will sometimes produce the effect of a second tooth behind

the first, on focussing downwards.

~ Here again, as with the armature of antenna i., everything depends upon getting the organ into exact profile in

one focal plane ; if it be tilted away from the observer, a right angle may easily look like an acute angle.

SECOND SERIES.—ZOOLOGY, VOL. X. 41

244, DR. G. H. FOWLER—BISCAYAN PLANKTON:

about as long as the principal bristle, with a few minute teeth. Antenna ii. with its

inner branch as drawn by Miiller (xxi. 3). The longer central bristle carries numerous

long fine hairs (? 8-10 pairs); both central bristles are curved, especially the shorter.

The longer basal bristle is about twice the length of the shorter.

Srace II. (magna stage).

FEMALE (Mean, 1°88).—Shell much as in the subsequent Stage I., but the rostrum

is less markedly bent downwards and the shoulder-ridge slightly more marked. Frontal

organ much as drawn by Miiller (Nap. Monogr. 1894, pl. v. fig. 8), but slightly more

swollen anteriorly, though not so much so as in hyalophyllum. Terminal spike very

rarely suppressed. Antenna i. with a long slender dorsal bristle carrying a few

extremely minute hairs. Antenna ii.: the longer central bristle carries fewer hairs

than in the subsequent Stage I. No basal bristles.

Mate (Mean, 1°77).—Shell much as in subsequent Stage I., but the anterior border

rises more sharply, giving a less bluff-bowed outline. Frontal organ much as in sub-

sequent stage. Antennai. without spines on the terminal jomt. The armature of the

principal bristle formed by 21-23 pairs of teeth, not markedly shorter at the ends than

in the middle; the distal teeth rather closer together; about the middle of the row

(compare Miiller, xxi. 12) the pairs are rather further apart, and the teeth are not set

quite evenly opposite one another, yet are not so markedly displaced as in Miller’s

drawing of subarcuata (xxi. 26); they are also more slender and longer than in that

figure. Antenna ii. as figured by Miller (xxi.17, 18); the hairs on the longer central

bristle fewer than in the subsequent stage (apparently 2-5 pairs). Longer basal bristle

about twice the length of the shorter.

Srace III.

FEMALE (Mean, 1°14).—Shell of the same general type as in the later stages, but

shorter and higher; shoulder-ridge hardly developed. Opening of the left asymmetrical

gland slightly prominent above the dorsal border when viewed from the right side. The

shell is sometimes slightly higher in front of the arcuation than behind it. Frontal

organ unsegmented, acutely pointed, the terminal part very little thicker than the shaft.

The pointed tip is usually in, or nearly in, the same line as the axis of the organ, but is

occasionally slightly bent downwards * (fig. 159). There are a few fine spines on the

ventral surface. Antenna i. with a short thickish dorsal bristle, not carrying hairs.

Antenna ii. with the longer central bristle generally carrying a few fine hairs, but

sometimes it is bald

Mate (Mean, 1:22).—Shell of a more female character than in subsequent stages ;

that is to say, the rostrum is more downwardly directed, and the posterior border more

curved. The shell is often slightly higher in front of the arcuation than behind it; and

is practically indistinguishable from the female shell of the same stage. Frontal

organ unsegmented ; the terminal portion is slightly broader than the shaft, generally

* Query, Ayalophyllum? but no lateral glands were detected.

THE OSTRACODA. 245

acutely pointed, with a few fine spines ventrally. Sometimes the point is less developed,

or the organ ends bluntly *. Antennai. The principal bristle is of female character,

that is, it carries a few scattered minute teeth. The two secondary flagella are a

good deal shorter than the principal and are differentiated from the sense-tubes.

Antenna ii. without hooks ; there are (?) no basal bristles; the longer central bristles

carry short hairs as in the female of this stage.

The two sexes can generally only be distinguished at this stage by the three bristles of

antenna i. in the male, and by the presence of the penis (not always easily seen).

Tort A Larva.

(Plates 21, 22. figs. 161-168.)

The morphology of the larvee classed under this head leaves little doubt that the

ereater number of them are attributable to magna. But it became obvious, at an early

period of the general investigation, that other forms were possibly represented among

them, namely hyalophyllum, zetesios, spinirostris, and loricata, forms belonging to the

magna and loricata groupst. The specimens of these larvae were very numerous, and

the difficulties of determining their length and sex were considerable. It is possible that

they might have been disentangled by another six months of work, but even then a

satisfactory result was not assured beforehand, nor did the probable gain seem likely to

compensate for the labour involved. All the larve, therefore, which exhibited certain

characters have been classed as “ A.”

The negative characters were :—the general shape of the sbell, in not showing the

rounded contours of curta, pusilla, and votundata (species which are eliminated by other

tests), or the elongate type of procera, brachyaskos, elegans, spinifera, and inermis, or

the elongate rostra of daphnoides, imbricata, and ametra; and the opening of the right

asymmetrical gland, not projecting as in rhynchena, nor displaced dorsally as in haddoni;

in several of these species the larvee have been satisfactorily identified.

The positive characters were a nearly straight posterior border, a straight or slightly

arcuate ventral border, with the greatest height of the shell markedly in front of the

middle of the length; a normal position of the asymmetrical glands, the opening of the

left one protruding above the dorsal border when viewed from the right side; the frontal

organ and central bristles of the second antenna closely resembling the type found in

magna at Stage III. The two latter characters, combined with a general similarity of

appearance (which is naturally more striking in the actual specimens than in outline

drawings), are the reasons for regarding the typical A larve as belonging to magna.

Their characters may be thus defined :—

Stace IV. (Mean + 0'8).

The males and females are only distinguishable from one another by the presence or

absence of the two rudiments of the penis. Shell witha nearly straight posterior border,

* Query, another species? but no other difference from the normal type was detected.

+ It is conceivable that the members of the mollis group, namely kampta and tyloda, may haye had epiplanktonic

larve; but as only two adult specimens of each were taken, they can be left out of count.

41*

246 DR. G. H. FOWLER—BISCAYAN PLANKTON:

which makes nearly a right angle with the dorsal border ; postero-ventral angle rounded ;

ventral border sometimes slightly arcuate, generally straight, sloping downwards so that

the highest point of the shell is well in front of the middle of the length. Frontal

organ unsegmented, the future terminal joint thicker than the stem ; its dorsal border

rising a little (sometimes sharply) at about half the length ; its ventral border convex and

with a few fine teeth in the male; terminating acutely. Antenna 1. with the principal

bristle of female character in both sexes; no differentiation of the accessory bristles from

the sense-tubes in the male, no dorsal bristle in the female. Antenna ii. with two

central bristles on the inner branch, the one more than twice the length of the other and

provided with a few stout hairs.

Stace V. (Mean + 0°5).

Shell much as in Stage IV., but rather shorter for its height, and with the down-

ward slope of the ventral border more marked. Frontal organ and Antenna i.

much as in Stage IV. Antenna ii. with a single short stout central bristle carrying

a few short hairs.

CoNCHG@CIA PROCERA, Miller.

? = C. decipiens, Miller.

(Plate 22. figs. 169-183.)

Only one sexual male stage was represented in the Biscayan collections, and this

agreed with the form hitherto described as procera. But the presumption is that a

second (final) male form exists in this as in the larger species. It seems likely that this

is to be found in the species named decipiens by Miiller, which he himself (p. 72) at first

ranked as procera, and only separated from it later in his investigation. Procera occurred

at all but one of the nine ‘ Valdivia’ stations from which he records decipiens, and

there is nothing in his description of the latter to make its identification with procera

improbable.

Srace IT.

Shell with the length more than twice the height, shoulder-ridge marked, postero-

dorsal angle rounded, posterior border convex; no postero-ventral angle is perceptible on

the left side, but on the right side the posterior and ventral borders meet at the opening

of the asymmetrical gland as two distinct curves; the opening is prominent, and is

placed further forward than is usual in other species. A small spine may or may not

be present on the right shell.

Mate (Mean, 1:11).—About twenty pairs of teeth on the principal bristle of antenna i.

are not uncommon. ‘There are sometimes a few short hairs on the longer central bristle

of antenna ii.

FrmALe (Mean, 1°16).—In figure 176 is drawn a slightly different type of antenna i,

from those drawn by Miiller (xiv. 3 to 6) showing the “ Albatross-bill ” end which occurs

in cophopyga and brachyaskos.

THE OSTRACODA. 247

Srace ITI.

Mate (Mean, 0°9)—Shell much as in Stage II., but the shoulder-ridge is not so

marked. Frontal organ simple, straight, unsegmented, the terminal joint not thicker

than the stem, ending sharply. Antenna i. with the principal bristle of female type.

Antenna ii.: the shorter central bristle is about three-fourths of the longer, the latter

may carry a few short hairs; one (? two) short basal bristles.

FEMALE (Mean, 0°9).—Shell much as in Stage II., but the shoulder-ridge is not so

marked. Frontal organ still projecting far beyond the end of antenna i., simple,

unsegmented, the terminal joint rather thicker than the stem, the end tapered.

Antenna ii. as in Stage IT.

Srace LV.

Matz (Mean, 0°65).—Shell with the height and length about equal; the ventral

border more sharply convex than in the later stages. Frontal organ ending bluntly,

simple, straight, still projecting well beyond the end of antennai. Antenna tii. as in

fig. 181 (female).

Frma.e (Mean, 0°62).—Shell more sharply convex ventrally than in the male of this

stage, height rather more than half the length. Frontal organ still very long, the

future terminal joint hardly thicker than the stem, tapering to a point. Antenna ii.

with one long and one very short central bristle.

Stace V.

FeMaze ? (0°5).—Shell much as in Stage IV. Frontal organ long, but of the

simplest type, slightly swollen towards the end, ending bluntly.

ConcH@cIA PUSILLA, Miiller, var. Mason, Miiller.

(Plates 22, 23. figs. 184-187.)

Only six specimens of this form were taken. In supplement to Miillers description,

it may be noted that it is at first extremely difficult to detect that the armature of the

principal bristle of antenna i. in the male consists of foliate plates and not of fine spines ;

their real form can only be seen if they are in exactly the right position. There were

about seven pairs, more or less in a ‘double row, followed proximally by about seven

more (not pairs) more widely spaced, appearing as a single row but really set alternately

in a double row. As Miiller’s figure of the shell (xvii. 836) was drawn from a “ stark

verbogene” specimen, the right shell of an undamaged specimen has been figured. In

the female of 0°8 mm. the frontal organ was as drawn in Miiller’s figure xvi. 35; in the

female of 0°6 as in his figure xvi. 36 ; there were two central bristles on the inner branch

of antenna ii. the shorter about three-fourths of the longer, both very slender and

hairless.

248 DR. G. H. FOWLER—BISCAYAN PLANKTON:

CoNCHECIA RHYNCHENA, Miiller.

(Plate 23. figs. 188-204.)

The specimens showed only one male stage with secondary sexual characters: it is

possible that ampta or tyloda may be the oldest stage of this species. However this

may be, the rhynchena stage is here regarded as Stage II.

Stace II.

The shells were a little less elongate than in Miiller’s figure (xxvi. 21), but the

characters of antenna i. in the male left no doubt of the identification. In both sexes

the opening of the right asymmetrical gland projects markedly beyond the shell-outline

(figs. 190, 195); the left lateral gland is found at the pronounced angle between the

posterior and the ventral borders. The following notes are supplemental to Miiller’s

description.

Mate (Mean, 2°28). Antenna i. The armature (Bldtéchen) of the principal bristle

was observed to amount to about 53 pairs of foliate teeth. The pad (Schwiele) on the

proximal accessory bristle appeared to be formed by an increase in the diameter of the

appendage, strengthened by chitinous three-quarter-rings ; it is opposite to the distal

half of the armature of the principal bristle: distal to it, are about eight pairs of stout

teeth, the pairs set widely apart from one another. On the distal accessory bristle are

20-40 pairs of stouter teeth, approximately opposite to the pad. Antenna ii.: there

are two central and two basal bristles, the shorter in each case is about one-half the

length of the other; all are apparently hairless.

FremaALe (Mean, 2'47).—The spines on the Frontal organ were rather stouter and

fewer than in Miiller’s figure (xxvi. 17a), but it agreed with this in general contour.

The terminal joint is markedly segmented from the stem, I have added drawings of

slightly sharper and blunter specimens, but all show the same general type and

spination. Antenna ii.: the central bristles as in the male, no basal bristles.

As some difficulty was found at first in separating this from 9? loricata, subjoined are the conspicuous

differences between them.

Rhynchena 3. Posterior border nearly straight, nearly perpendicular to the dorsal angle, no

arcuation of the ventral border, marked sculpture at the anterior end of the shell. Postero-dorsal

glands present, frontal organ segmented from the stem, opening of the right asymmetrical gland

markedly projecting.

Loricata 2. Posterior border convex, extending behind the perpendicular from the dorsal border,

ventral border arcuate, sculpture of the anterior end of the shell inconspicuous. No postero-dorsal

glands, frontal organ incompletely segmented from the stem, opening of the right asymmetrical gland

conspicuous but not markedly projecting beyond the shell-outline.

Stace IIT.

Mate (Mean observed * 1°75, probable + 1°55).—Shell rather less elongate than in

the subsequent Stage IL., posterior border slightly convex, opening of right asymmetrical

gland slightly projecting as before. (The rostrum in fig. 190 is not quite in profile,

and looks shorter than it really is.) Frontal organ unsegmented, the future terminal

* Only two specimens of this stage were seen.

THE OSTRACODA. . 249

joint swollen on the ventral border, diminishing suddenly to a narrower tip, the end

rounded and carrying an insignificant spike; a few fine spines on the ventral border.

Antenna i. with the principal bristle of female character. Antenna ii. without hooks,

the central bristles as in the later stage: there are two basal bristles, the one very tiny,

the other fairly long.

Frmae (Mean, 1:60)—Shell slightly more elongate than in Stage IT., but retaining

the projecting opening of the right asymmetrical gland and the postero-dorsal glands.

Frontal organ thicker than the stem, but incompletely segmented from it, tapering

to a blunt tip, carrying a few fine spines ventrally. Antenna i. with a hairless dorsal

bristle (accidentally omitted in fig. 200). Antenna ii. with the shorter central bristle

about two-thirds of the other; both hairless.

Stace IV.

Mate (Length, 1:1)—Shell with postero-ventral angle more rounded than in

Stage III., posterior border at a slightly obtuse angle to the dorsal border, ventral

border nearly straight ; opening of right asymmetrical gland prominent, postero-dorsal

glands just recognisable. Frontal organ short, slightly thicker than the stem,

unsegmented, spineless. Antenna ii. with one fine basal bristle (? two); the shorter

central bristle half the length of the other, both hairless.

Frmae (Mean, 1:04).—Shell with postero-ventral angle more rounded, postero-dorsal

angle more obtuse, and ventral border more convex than in later stages; the highest

point of the shell lies at about the middle of its length. Opening of the right asym-

metrical gland projecting, but postero-dorsal glands not recognizable. Frontal organ

elongate, simple, the terminal joint not segmented from the stem, ending bluntly ; one or

two fine spines on the ventral surface. Antenna i. without dorsal bristle. Antenna ii.

with central bristles as in the male.

STAGE V.

Frmate (Mean, 0:70).—Shell sharply convex ventrally; the opening of the right

asymmetrical gland is prominent, but does not project so much as in the later stages.

The left lateral gland is already distinguishable, but very small. Frontal organ

simple, short, blunt ; the future terminal joint slightly thicker than the stem, constricted

distally. Antenna ii. with a single hairless bristle of medium length.

The specimens at 0°6 mm. may perhaps belong to an earlier Stage VI., but their

determination is naturally rather uncertain. In them the opening of the right asym-

metrical gland resembled that of macromma (Miiller, xvii. 12), and was very high up, at

nearly half the height of the shell.

CoNCH@CIA ROTUNDA'TA, Miller.

(Plates 23, 24. figs. 205-224.)

According to Dr. Miiller, the shells of this species exhibited « remarkable variation

in shape, the height being anything from 41 to 57 per cent. of the length. Now in all

other Halocypride which I have handled the shell-shape is very fairly constant, and the

general contour gives one of the most reliable specific characters, but its diagnostic

250 DR. G. H. FOWLER—BISCAYAN PLANKTON:

value would be seriously weakened if so great a range of variation were possible as is

shown in Miiller’s figures, pl. xvii. 28, 24, and 25, 26. Fortunately, it appears that this

extreme range of possible contour is due, not to individual variation, but to the different

shapes of the shells at Stages I. and II. So far as I have seen (with the exception of

one abnormal specimen*) all specimens at Stage I. were of the elongate type; at

Stage II. they are never so elongate as at Stage I., although both exhibit a certain

amount of individual variation. At the earlier stage they become even more rounded.

A glance at the figures of the shells on Plate 24 will show the changes of form which

accompany the successive metamorphoses.

For reasons which will appear in the Developmental Part (p. 273), the means are only

wide approximations.

Srace I.

Mate (Mean, 1:0).—Shell very elongate; the height to the length as 1 to 1:9; the

opening of the left asymmetrical gland far forward, near the rostral incision. The

shoulder-ridge slight; the posterior angle markedly rounded, the posterior border

strongly convex, the ventral angle markedly rounded ; the ventral border nearly straight

and generally almost parallel to the dorsal border, the shell being very slightly highest

in the posterior third. Frontal organ and Antenna i. as described and figured by

Miller (xvii. 29, 34); the armature of the principal bristle consists of about 10-12 pairs

of spines, of which the distalmost five or six pairs are close together, the more proximal

are placed at gradually increasing intervals. Antenna ii. as described by Miiller ;

there are two very small basal bristles; of the central bristles the one is about twice

the length of the other ; both are hairless.

Frma.e (Mean, 1:1).—Shell very elongate; the length may be more than twice the

height; the shell is sometimes more markedly highest in the posterior third than is

shown in fig. 215. The posterior border is more sharply convex than in the male,

but otherwise similar to it. Frontal organ rather variable: the normal type as in

fig. 216 (compare Miiller’s figures, xvii. 30 to 33). Antenna ii. with two hairless

central bristles, the longer about twice the length of the shorter; sometimes with two

tiny spines in the position of basal bristles.

Stace II.

Mate (Mean, 0°75).—Shell much less elongate. The height to the length about as

1to17. From the posterior end of the dorsal border runs a steady sharply-convex

curve, which is unbroken till just below the rostrum, obliterating the posterior angles.

The greatest height is near the middle of the length, the ventral border strongly convex.

Frontal organ with short, sharply segmented, terminal joint; the dorsal border

depressed about the middle of its length, with a few fine spines proximally; the ventral

border correspondingly swollen, then constricted, with numerous fine spines, ending

* The specimen, a male of 1:0 mm., that is to say of the length of Stage I., had not developed secondary sexual

characters—the armature of the principal bristle of antenna i., the hook-joint on antenna ii., and the form and

spinulation of the frontal organ; it had been arrested at Stage III. Such cases of arrested sexuality have been

described from other groups; the testes were rather small, but I could see no trace of “ parasitic castration.”

THE OSTRACODA. 251

bluntly. The general type is that of Stage I., but shorter and plumper. Antenna i.

with an armature of about 8 or 9 pairs of spines, the distal four or five pairs close

together, the remaining pairs set at increasing distances from one another. Antenna ii.

as in Stage I., but with no basal bristles.

Fremater (Mean, 0°79). -Shell much less elongate, the height to the length about as

1 to 1:4 or 1:5; the greatest height behind the middle of the length. Frontal organ

less spinous, but otherwise this and the antennze resemble those of Stage I.

Stace ITT.

Mate (Mean, 0:61).—Shell much as in Stage II. but shorter; the height to the

length about as 1 to 1-4; both posterior and ventral borders very sharply convex, the

ereatest height about the middle of the length. Frontal organ resembling that of

the female at Stage II., with a very few spines on the ventral border. Antenna i,

with the principal bristle of female character. Antenna il. without hook-joint, other-

wise resembling that of the later stage.

FEMALE (Mean, 0:61).—Shell of about the same proportion of height to length as in

the later Stage II., but more semicircular, owing to the greater rounding of the postero-

ventral angle. The opening of the left asymmetrical gland further back in the length.

Frontal organ blunt, spineless, straighter.

Stace IV.

Mate (Mean, 0:41).—Shell projecting less behind a perpendicular from the posterior

end of the dorsal border; opening of left asymmetrical gland far back. Frontal

organ spineless, unsegmented, but much as in Stage IIT.

Fremate (Mean, 0:-40).—Shell much as in Stage II]. Frontal organ straight and

undifferentiated. Antenna ii. without central bristles.

CONCHGCIA SPINIFERA, Claus.

(Plate 24. figs. 225-235.)

Three stages were represented, of which only one showed male secondary sexual

characters. ‘The oldest captured is therefore considered to be Stage I.

SraceE II.

Frmate (Mean, 2°12).—Shell with marked shoulder-ridge; the posterior border of

the left shell is nearly at right angles to the dorsal border (except for the slightly

truncated postero-dorsal angle); on the right shell, a slight convexity under the spines

precedes the gently curved posterior border, The opening of the right asymmetrical

eland is approximately at the postero-ventral angle; is is not prominent beyond the

shell-outline. The ventral border gently convex; the highest point of the shell is at

about the middle of the shell-length. A group of (generally four) large granular gland-

cells is almost always to be found near the antero-ventral angle. Frontal organ and

Antenna i. as figured by Miiller (ix. 14, 15) except that the dorsal bristle of antenna i.

was observed to reach nearly to the end of the frontal organ. Antenna ii. with two

SECOND SERIES.— ZOOLOGY, VOL. X. 42

252 DR. G. H. FOWLER—BISCAYAN PLANKTON:

central bristles, the one about two-thirds of the other, each with a very few fine short

hairs. One at least of the terminal bristles may carry a row of short spines.

Mate (Mean, 1'80).—Shell not markedly different from that of the female. In the

specimen drawn in figure 225 a blunt process replaced the spines; this may have

been due to damage; the spines are generally conspicuous. The characteristic cephalic

organs as drawn by Miiller (pl. ix.).

Stace III.

Fremate (Mean, 1'44).—Shell of the same character as in Stage II., but the rostrum

somewhat less markedly bent downwards. The antero-ventral gland-cells persist. Frontal

organ spineless, unsegmented; of the same general character as in Stage IL., that is,

a swollen convex ventral border is suddenly decreased anteriorly to form with the dorsal

border an acute tip. Antenna i. usually (? always) without a dorsal bristle. Antenna 1i.

as in Stage IT., but the central bristles are apparently hairless.

Mate (Mean, 1:41).—Shell as inStage II. Frontal organ approaching the female

type of Stages II. and III., but shorter, and with the dorsal border rising suddenly about

the middle of the future terminal joint; spineless, unsegmented. Antenna i. with the

principal bristle of female type. Antenna ii. as in female of Stage II.

Stace LV.

Ferma e (Mean, 0'98).—Shell much as in the later stages, but the posterior border is

rather straighter, and is not shaved off so much at the postero-ventral angle. One or

two of the large antero-ventral gland-cells are generally recognisable. The spines of

the right shell are sometimes present. Frontal organ ending bluntly, the ventral

border decreasing suddenly near the tip as before: the organ is shorter in proportion to

the antenne. An'tenna ii. with the longer central bristle about twice the length of

the shorter.

Mate (Mean, 1:03).—Practically indistinguishable from the female, except for the

rudiments of the penis.

CONCH@CIA SPINIROSTRIS, Claus.

=C. porrecta, Claus.

(Plates 24, 25. figs. 236-246.)

The relation of the different stages is discussed in the Developmental Part (p. 276).

Stace I. ( porrecta stage).

Mate (1°33 mm.). Shell of the type of magna male: the shoulder-ridge well

developed; the opening of the right asymmetrical gland rather prominent posteriorly.

The posterior border nearly at right angles to the dorsal border, with a slight re-entrant

curve; ventral border nearly straight. Frontal organ mueh thicker than the stem;

constricted centrally, thickest distally; spines very few and short. Antenna i.: the

armature of the principal bristle appeared to consist of about 16 pairs of saw-like teeth,

followed by about 11 pairs of spine-teeth; the latter so markedly alternate as to suggest

THE OSTRACODA. 253

a single row unless viewed directly from above. Antenna ii. as figured for Stage IT. ;

the shorter central bristle about two-thirds of the longer; the latter with a few very

long hairs; there are two basal bristles, the one more than twice the length of the

other, both slender and hairless.

The exact shape of the saw-teeth is difficult to make out owing to their minuteness

and high refraction. They appeared to have rather the shape given in fig. 238 than

that shown in Miiller’s drawing (xxii. 25). The sub-cuticular teeth shown in his figure

appeared in one specimen at Stage IT., and probably indicated an approaching moult.

Frmate of this stage not observed.

Stace IT. (spinirostris stage).

Matz (Mean, 0°93).—This is hardly distinguishable from Stage I., but (1) the posterior

border of the shell is rather straighter; (2) the teeth on the armature of the principal

bristle of antenna i. were about 8-11 pairs of saw-teeth and about 8-9 pairs of spine-

teeth; (3) the frontal organ was rather slenderer, not much thicker than the stem.

Femare (Mean, 110).—Shell with a sharply curved posterior border, and a fairly

prominent opening to the right asymmetrical gland; no postero-ventral angle. The

ventral border is very slightly arcuate, the highest point well behind the middle of the

shell-length; tapering gradually forwards. Frontal organ of very larval appear-

ance, spineless, unsegmented, only slightly swollen anteriorly, terminated acutely.

Antenna ii. with the shorter central bristle about two-thirds the length of the

longer, the latter with a few fine short hairs at its base. No basal bristles.

The female is difficult to identify, owing to the fact that the frontal organ has the

characters (or, rather, absence of positive characters) which one has learnt to associate

with larvee of earlier stages in other species (smoothness, transparence, symmetry of

dorsal and ventral borders, thin wall, absence of segmentation, &c.). But as some

females carried comparatively large ova (0°08 mm. diam.) they were not far from

maturity.

Srace III.

Mate not observed.

FEMALE (Mean, 0°75).—Shell with the posterior border straighter than at Stage IT. ;

no postero-ventral angle, ventral border slightly convex. Frontal organ as in Stage II.,

but shorter. Antenna ii. with two central bristles as in Stage IT., but hairless.

CoONCHG@CIA TYLODA, Miiller.

A single male specimen of 2°8 mm. in fair preservation agreed with Miiller’s figures

and description. On the principal bristle of antenna i, there seemed to be about 57 pairs

of leaf-like structures (which at first look like very fine spines), distal of these are

3 or 4 short spines directed distally. Antenna ii. carried two basal bristles (Miiller

figures one only), the one about two-thirds the length of the other.

A pair of empty shells which carried the characters of this species was also taken;

their length was +2°7 mm.

42%

DR. G. H. FOWLER—BISCAYAN PLANKTON:

CONCH@CIA ZETESIOS, sp. n.

(Plate 25. figs. 247-253.)

Only females of this undescribed form were taken by the ‘ Research, representing

two stages and in very small numbers. The species obviously belongs to the magna

group. While the shell-contour to some extent resembles that of ‘macrocheira,’ its

frontal organ and the slender longer bristle of the inner joint of antenna ii. are very far

from the magna-macrocheira type; nor can it be fitted into the lengths which have been

worked out for that series. It is remotely possible that it may be a dimorphic partheno-

genetic form of magna, but parthenogenesis has not yet been shown to occur in the

Halocypridee (compare p. 308).

Stace (?) I.*

FEMALE (Mean, 2:'42)—Shell very foursquare, shoulder-ridge slight; the posterior

border steadily convex; the opening of the right asymmetrical gland rather high, that

of the left rather far forward; no postero-ventral angle; the ventral border very long,

markedly arcuate, generally so full anteriorly that the highest point of the shell is in

front of the arcuation ; the anterior border very bluff; the rostrum so bent downwards

that its anterior face is at right angles to the dorsal border, and if produced would

nearly (or quite) make a tangent to the anterior border. Frontal organ very long;

the terminal joint imperfectly segmented from the stem; the proximal half of the

terminal joint is rather thicker than the stem; tlie distal half is much thicker and

terminates in a blunt downwardly directed spine; it carries a few spines on its dorsal

border only. Antenna i. with a very long dorsal bristle, the distal half of which

carries long fine hairs. Antenna ii. with a very low peg (Warze, Mamillar-hécker),

devoid of basal bristles; the longer central bristle is about twice the length of the

shorter and carries short hairs; the shorter also in some eases has hairs.

Stace (?) IT.

Frmate (Mean, 1:5).—Shell with a more convex posterior border; the anterior

part of the ventral border is fuller, so that the highest point of the shell is far in front

of the arcuation; the rostrum is bent at first downwards, then inwards; in other

respects the shell is as in the later stage. Frontal organ of the same general type as

in the later stage, but less swollen and spineless. Antenna i. with a dorsal bristle,

shorter than in the later stage, and hairless. Antenna ii. as in the later stage.

ConcHa@ctia B.

(Plate 25. figs. 254-257.)

A single female from 220 (750-500 fathoms), 17 mm. in length, was possibly

referable to the penultimate stage of dorsotuberculata. 'The general outline of the

shells agrees sufficiently with Miiller’s figure x. 1, allowance being made for a small

difference between the sexes. The opening of the left asymmetrical gland is not nearly

so far forward as in dorsotuberculata, but is further forward than is normal in

* The ovary was in all cases so poorly developed, that it is possible that the specimens were only semi-mature.

THE OSTRACODA. 255

Conchecia; it is possible that (as certainly happens in volwndata) the opening shifts

forward with successive moults.

Shell very clongate, the length about twice the height; dorsal border straight ;

opening of left asymmetrical gland about + of the border from the postero-dorsal

angle. Posterior border a steady curve, meeting the ventral border without any

postero-ventral angle; ‘ventral border parallel to dorsal border, slightly arcuate

centrally; the anterior border beginning very far forward. The right asymmetrical

gland in the usual position. Frontal organ with three long fine spines dorsally, and

about ten ventrally. Antenna i. with a dorsal bristle carrying very minute hairs.

Antenna ii. with two central bristles, the longer nearly twice the length of the shorter,

and with short stout hairs; the shorter with fine hairs.

If it be not dorsotuberculata, the specimen probably belongs to an undescribed species.

ConcHactiaA C.

(Plate 25. figs. 258-262.)

A single male with secondary sexual characters, 1°1 mm. long, occurred in haul 357%

(500-400 fathoms). A comparison of the figures given here with Miiller’s figures of

haddoni, incisa, orthotrichota, &c. (pls. 18, 19) will show that the specimen is obviously

referable to his Jéspinosa group. The shells had been slightly damaged, but I saw no

trace of a postero-dorsal spine; the angle had, however, somewhat suffered.

It may possibly prove to be a small specimen of the penultimate stage of haddoni, but

the size and the supposed contour of the postero-dorsal angle are against this. In addition

to the features figured, may be mentioned that the armature of the principal bristle of

antenna i. (which I failed to get into profile position for drawing) much resembled that

of incisa (Miller, xix. 7), and consisted of about 18 pairs of fine close-set teeth, markedly

directed backwards; there were two central bristles on antenna ii., the one about

two-thirds the length of the other.

Hatocyrris GLoposa, Claus.

(Plates 25, 26. figs. 263-278.)

Stace I.

MALE (2:1 mm.) *.—Shell with the height about § (65 p. c.) of the length; the two

shells together, viewed from a longitudinal vertical plane, are not subspherical as in the

female, but are hardly thicker from right to left than in an ordinary Conchecia.

Rostrum well developed, forwardly directed, placed at the end of the dorsal border, not

far down the anterior border as in the female. Shoulder-ridge inconspicuous, postero-

dorsal angle rounded, posterior border a steady curve with the opening of the right

asymmetrical gland about the middle of the height, no postero-ventral angle. ‘The

ventral border flatter than in the female. Frontal organ short, straight, segmented ;

without hairs or spines; the terminal joint forms a slight angle with the thicker stem,

and is thinnest about the middle of its length. Antenna i. of female type, with four

* Miiller’s single specimen was 2:25 mm,; the specimens were probably at the oldest stage, if Halocypris follows

the proportions usual in Conchacia.

256 DR. G. H. FOWLER—BISCAYAN PLANKTON:

sense-tubes subequal in length, and one long bristle which carries few minute hairs.

Antenna ii. The right and left hooks are nearly symmetrical and subequal: the

right is rather the stouter of the two; it begins by a short straight piece, and after an

angle forms a sickle-shaped curve. The two central bristles (much foreshortened in

fig. 267) are subequal, the one carrying short fine hairs. There are two basal bristles,

the one nearly twice the length of the other.

The single specimen was in fair condition, fortunately, as the cephalic organs were

hitherto undescribed.

Ferma e (Mean, 2°51).—Shell with the height about 73 per cent.* of the length. The

two shells together form almost a sphere when viewed from a longitudinal vertical

plane. The postero-dorsal angle is rounded, the posterior border slightly convex, no

postero-ventral angle, a strongly convex ventral border. Rostrum bent sharply

downwards, its apex at about two-thirds of the height of the shell; it projects very

little beyond the anterior border. Frontal organ as described and figured by Miller

(vill. 19), with the addition usually of a thickened groove (? joint) near the base of the

terminal segment. Antenna i. as described by Miller. Antenna ii. with two

central bristles, the one about two-thirds of the length of the other, both hairless; there

is sometimes also a small basal bristle.

Srace IT.

Fema e (Mean, 1°54).—Shell with the height about 84 per cent. of the length; it

agrees with Stage I. except in being proportionately higher. Cephalic organs as

in Stage I.

Stace IIT.

Frmaxe (Mean, 0°95).—Shell nearly as high as long, very sharply curved ventrally.

Cephalic organs as in later stages.

Stace IV.

FEMALE (Mean, 0°61).—Shell as in Stage ITI. Frontal organ and antenna i. as in

later stages. Antenna ii. with one long central bristle.

Srace V.

FEMALE (0'4 mm.).—Shell as in Stage TV. The frontal organ and antenna i. were

unfortunately broken in dissecting the single specimen, Antenna li. as in Stage LV.

ARCHICONCH@CIA CUCULLATA, Brady.

wo males and two females of this rare species were captured. The females were

apparently at Stage II. or III., but offered no structural differences from Miiller’s

description and figures which require comment here.

* The specimen figured by Dr. Miiller (viii, 13) appears to have been tilted a little ventrally,

THE OSTRACODA, 257

CYPRIDINID.

CYPRIDINA CASTANBA, Brady.

(Plate 26. figs. 279-281.)

Two females, apparently of Stages I. and IT., respectively about 6:0 and 4:0 mm. in

length, occurred in haul 32m. The larger specimen carried ova free between the

shells posteriorly. The smaller was pale in colour, except for the eyes, and for the

stomach which had already the “chestnut” tint of the adult.

Besides these, two larvee of 1‘8 mm. and one of 1°9 mm. were taken. Dr. Miiller

figures (xxxiv. 10) a larva of this description, but does not give its length. As he points

out, the shells are more circular and less elliptical at this early stage.

The complicated arrangement of bristles and selvage (Sawm) at the rostrum, which

he figures (xxxiv. 12) for the adult, is not quite identical with that of these larvee

(fig. 281) ; the selvage is traceable from above the rostrum along the ventral border as far,

at least, as the most prominent point of the posterior border, but is very narrow on the

ventral and posterior borders.

The younger stage is probably identical with Vavra’s Cypridina obesa.

GIGANTOCYPRIS PELLUCIDA, Miiller.

(Plate 26. fig. 282.)

Two specimens, the one perfect (and, if I remember right, alive), were obtained from

great depths. By size they belonged to Miiller’s species pellucida: the perfect specimen

measured about 13 mm.; in the other the shells were much crumpled and torn, but

they seemed to be of about the same length. 1 regard it, however, as possible that

pellucida is the penultimate stage of agassiziz.

The 13 mm. specimen (which was not dissected) contained about 28 embryos between

the shells posteriorly: one of these was extracted and is represented in fig. 282; it was

still encased in a shell-membrane, and showed five pairs of appendages; the shell-edges

had already begun to grow downwards.

This and Cypridina castanea were the only cases noticed, in the whole collection,

of ova or embryos being carried by the mother after extrusion.

III. DEVELOPMENTAL PART.

The general method of handling the question of the successive moults—(1) by plotting

the numbers observed at each length and noting the range of the curves thus formed ;

(2) by testing these with a growth-factor found empirically—has been sufficiently

explained in the Introduction (pp. 224-226). The supposed law of growth by approxi-

mately similar increments at successive moults, here styled Brooks’s law, requires to be

re-tested on larger Crustacea, where a hundredth of a millimetre will be a negligible

258 DR. G. H. FOWLER—BISCAYAN PLANKTON:

percentage of the measurements involved *. The present work, based on such unfor-

tunately small forms as Ostracoda, can at best be merely pioneer work, and cannot

pretend to mathematical accuracy. The means here given can only be approximations

in most cases, owing not only to the minuteness but also to the scarcity of specimens.

Although in this case unavoidable, it is, mathematically speaking, an absurdity to treat less

than a hundred cases for problems of frequency. If the means are only approximate,

so also must be the growth-factors. Further, it is possible that not only are the means

and growth-factors mere approximations, but also the law itself, as here phrased. The

actual increase at each moult is probably not so simple that the same growth-factor will

apply exactly at every moult, even in Ostracoda of small size and few stages; and, as

will be seen later in a discussion of measurements of crabs and lobsters, the factor

certainly undergoes modification as growth proceeds, in large forms with numerous

moults. On the other hand, J have little doubt that the law as phrased on p. 224 is a

sufficiently accurate weapon for the zoologist to use in combination with the morpho-

logical evidence, even if the words “fixed percentage”” may require revision at the

hands of the mathematician.

After writing the larger part of this paper, I had the great advantage of the help

and criticism of Professor Karl Pearson from the mathematical standpoint. He

expressed the opinion that while valid statistical evidence is given here in many cases

for that separation of the stages which I have proposed, in others this evidence is

wanting [in some of these latter, however, it is supplied by the morphological changes

which indicate that an intermediate moult has oceurred]. Professor Pearson, regarding

the “stairease-growth” of Crustacea [discontinuous growth by moults] as likely to fit in

eventually with the laws of growth of other organisms, pointed out that Brooks’s law

could only fit in with a relatively small portion of the general growth-curve; that it

might be a reasonable approximation to a portion of it, but that mathematically it is

clear that many other formulze would accomplish the same result; that in most cases

I have only recorded three stages, and have accordingly only two ratios of growth, and

that if these were not very widely different one might easily get a mean value within

the probable error of the results. In sum, he was not convinced of my conclusions

being more than a first approximation based on three stages. With this verdict I am

content. I believe that I have carried the matter about as far as Ostracoda will admit,

and must leave to others the further development of the suggested law of growth on

more favourable material.

It is reasonable to suppose that all the species of Conchweia follow the same rhythm

of moults ; and on this is based the working supposition that they all exhibit two stages

with secondary sexual characters in the male. ‘These two stages have heen recorded

(in one or both sexes, in this or other memoirs) for curta, daphnoides, elegans, haddoni,

hyalophyllun, loricata, magna, rotundata, and spinirostris (supposing, that is, that my

identifications are correct); and their occurrence has consequently been inferred in

ametra, imbricata, procera, rhynchena, and spinifera.

* Observations on lobsters and crabs will be found on pp. 279-281.

THE OSTRACODA. 259

HALOCYPRID&.

COoNCH@CIA AMETRA, Miiller.

The specimens captured were unfortunately far too few to yield satisfactory means,

but three stages are clearly visible in both sexes.

The actual observations were as follows :—

Qe mm. Shin

(2 3°5

Stage II. | 1 3-4.

Mean, 3°30. | A 3.8

b 3°2 1

L a 2} Stage II.

3-0 1 Mean, 3°10.

aa ee {1 23 1

ome lid 2:2 1 | Stage III.

271 Mean, 2°16.

20 1

Stage IV. {1 15 Sonia

Mean, 1°42. 4 14

Taste B.—Total specimens measured: 17.9 + 8 ¢= 25.

Taking an approximate growth-factor of 1°5 mm. for females and 1'4 for males, the

unknown Stage I. of this species would measure about 5°0 mm. in the female, and 4-4

in the male.

CoNCHECIA BRACHYASKOS, Miiller.

It would have been clear that there were at least two male and two female stages

here, even if anatomical study had not shown them; but the specimens were too few to

allow of any guess at their mathematical relations.

The actual observations are as follows :—

Cee mm. Ge

1 14

4 1:2

uci!

2 LO

2 0-9 l

1 08

Taste C.—Total specimens measured: 10 9 +6 ¢ = 16.

Concua@cra curta, Lubbock.

This species is by no means easy to manipulate; it is very difficult to poise the almost

spherical shells in the profile position which is necessary for accurate measurement and

drawing, and the shells are thin and readily distorted. Further, owing to its small size,

SECOND SERIES.—ZOOLOGY, VOL. X. 43

260 Dk. G. H. FOWLER

BISCAYAN PLANKTON:

the successive stages seemed to overlap as in rotundata (p. 273). While this overlap

may be partly due to the comparatively rough method of measurement adopted, it is

certainly the case at one point that the highest measurements of one stage coincide with

or actually overlap the lowest measurements of the next oldest stage. Thus, for

example, in a few male specimens measured to a second place of decimals, at Stage IT.

(lower sexual stage) were found the lengths 0°82, 0°80, 0°78, 0°75, 0°73 mm.; and at

Stage ILI. (without secondary sexual characters) the maximum length observed

was 0°82 mm.

On the whole, the possible errors were so great that it did not seem worth while to

take a long series of measurements, as has been done with most of the other species

described. There are not only the personal error, the errors due to parallax and

refraction, the error due to faulty position of the specimens, and the large error due to

distortion of the shell, to be considered ; these all apply also to bigger species (in which

they would seriously affect the second place of decimals) ; but, further, all these errors

are intensified by the minuteness of the specimens of cuvia, so that they together amount

to a far larger “ percentage error” than in the larger forms.

A good many specimens were measured to a second place of decimals (about 15 mm.).

The results seemed to be perfectly worthless. The only chance of accurate measure-

ment to a second place was of an undistorted shell from the inside—that is, of the right

shell when the left has been turned back; this was often impossible when the animal’s

body lay over the posterior border, or its appendages over the anterior border; and a

comparison of such measurements with those taken before the shell was opened (when

the true edges cannot be seen), or taken from the turned-back shell (distorted by

opening), gave widely different results.

If wy association of sé¢gmatica with curta he correct, we can recognize in the males a

Stage I. (“ st¢gmatica stage”), with a mean somewhere about 1:0 mm.; a Stage II.

(‘‘curta stage’’), which may be at least as long as 0°82 mm., and as short as 0°73 mm. ;

and a Stage II. (without secondary sexual characters), which may be as long as

0°82 mm., and is probably a later stage than the numerous specimens of about 0°55 mm.

In the female the stages seem to be impossible to separate with any precision, as there

is less morphological alteration from stage to stage than in the male; but I think that

Stage I. hada mean of about 0°9* or 1:0 mm., Stage II. about 0°7 mm., and Stage III.

about 0°5 mim.

This total result is eminently unsatisfactory as compared with that obtained from the

larger species ; but.a longer series of measurements from the ‘ Research’ collections would

not better it, because the weakest point of fewest measurements lies about Stages I.

and IJ., and the larger specimens (of 0°9 and more mm.) were entirely confined to the

lower strata (below 400 fathoms), from which every available specimen has already been

measured. Nor would additional measurements of the smaller specimens (except in

order to draw a line between male Stages II. and III.) avail to resolve the overlapping

* Tt is noticeable that according to Miiller the curta group is almost unique in having the males equal to or

longer than the females.

THE OSTRACODA. 261

curves, in the absence of marked morphological differentiation. The mean of 14 males

at Stage IT. measured to the second place was 0°76 mm., which seems to show that the

curve, the apex of which is at 0°7, contains the materials of two curves.

The actual measurements from which the curves in fig. B have been plotted are as

follows :—

Oe mm. de

el 1

7 10 6

13 0:9

10 0°8 8

37 O7 22

7 06 8

Ad 0-5 31

3 0°4

3 03

Taste D.—Total specimens measured: 124 ? +76 g =200.

It being impossible to get a satisfactory mean of the lengths, owing to the overlapping

of the curves, it is worth notice that the modes of the curves of the (supposed) three

oldest stages correspond to Brooks’s law as well as could be expected :—

Males: growth-factor, 1°42. Females: growth-factor,

0:50 x 1:42 =0°71 0:50 x 1:-40=0°70

0-71 x 1:°42=1°00 0:70 x 1:°40=0°98

Until a more accurate inethod of measurement for these minute specimens has been

devised, this approximation will have to serve.

Fig. B.

CoNCHCIA DAPHNOIDES, Claus.

The best method of measurement for this species required consideration, because the

contour of the shell is so utterly different from that of the other species handled.

43*

262 "DR. G. H. FOWLER—BISCAYAN PLANKTON:

Judging by the lengths recorded, Dr. Miiller seems to have measured a “ length over

all,” from the tip of the rostrum to the tip of the posterior spine. This was not adopted,

firstly, because both spine and rostrum are often broken or bent; secondly, because, as

they appear to be disproportionately longer in the older stages, they would probably

not give a true standard of comparative growth at different stages; thirdly, because

the measurement over all would not be comparable with those made in the other

species, where the “length” is from the projection of the anterior border below the

antennal incision, backwards, parallel to the dorsal border. Fortunately, it is generally

easy to open and turn back the left shell in daphnoides, without serious distortion; this

having been done, the base of the 0 on the micrometer-ocular scale was laid carefully to

the most prominent point on the anterior border of the left shell, the scale laid as

closely parallel as possible to the dorsal border; the point where the posterior curve

upwards to the spine intersected the base-line of the scale was then read as the

“Jeneth.” This reading seemed to be at any rate comparable with that taken in other

species; but the experimental error is perhaps rather greater in daphnoides, as the

posterior curve probably varies in radius to some extent. While therefore the individual

measurements are perhaps less accurate than in the other larger species, they are,

doubtless, sufficiently so to give a reliable mean, owing to their number.

Judging by the analogy of more plentiful species, there can be little doubt that

daphnoides var. minor, Miller (=Jlacerta, Brady & Norman), is the penultimate stage of

daphnoides var. typica, Miiller, that is to say, the lower stage with secondary sexual

characters. Unfortunately this stage was not represented in the Biscayan collections,

but a rough measurement of Miiller’s figure (xxxi. 1) yields a length of about 1:8,

measured by my method. A few specimens of var. t¢ypica were measured by both

methods, but no relation appeared between the two sets of figures *.

The actual measurements were as follows :—

9. mm. Jd

(il 35

1 54

5 3:3

| 41 32

Stage I. | 15 31

Mean, 3°08. } 31 3:0

9 2°9

| 5 2°8

Pes) 27

{ ] 2°6

9-5 Wal)

o-4 24 Stage I.

2-3 48 ( Mean, 2°34.

2-2 BJ

Stage III. 1 1:2

TaBLE E.—Total specimens measured: 112 9 + 88 $ = 200.

* From tip of rostrum to tip of spine they varied from 5:0 to 5'o mm.

“THE OSTRACODA. 263

Tn addition to the numerous specimens of Stage I. there was a single female specimen

of (apparently) Stage III.; this with the aid of a slide-rule enables one to make an

empiric guess at the mean of Stage II. With a growth-factor of 1°6 for females it

appears that 1:2 x 16=1:92; 1:92 x 16 =3:07; and we may fairly presume that

the mean of Stage IT. will be a little more or less than 1°9 mm.*.

Tt will be noticed that the curve of females at Stage I. shows a distinct double

hump, which can hardly be attributed to scarcity of specimens.

Fig. C.

CoNCHECIA ELEGANS, Sars.

This species presents the same difficulty as some of the other small forms—namely,

of an overlapping of the curves in the male between Stages IT. and III.; some

specimens of 1:0 mm. were observed to have not yet developed secondary sexual

characters which were already shown by others at 0°99 mm. ‘The same thing

appeared to be the case in the females at Stages IV.-III., ITIL, but their smaller

morphological differentiation renders it less obvious.

As in rotundata (p. 273) and curta (p. 259), the differences in length between the

successive stages are so small that measurement to only one place of decimals does not

bring out clearly the boundaries between stages which are so noticeable in larger species,

such as magna.

In consequence of these two unfavourable conditions, it is not possible to get really

satisfactory means for the various stages; but, taking the means for female specimens

(compare fig. D, p. 264) of 1:1 and 1:2 mm., of 0°8 and 0°9 mm., and the median at

0:6, so as to eliminate the probable overlapping at 1:0 and 0:7 mm., we arrive at the series

0°6, 0°86, and 1:12. To this a fair approximation can be got by a growth-factor of 1°32 :

* Since this was written, I have measured the two specimens of “ lacerta” taken by the ‘ Research’ in the Faeroe

Channel (Proc. Zool. Soc. 1903, p. 122) and now in the British Museum. They were females of 2:0 mm. in length.

264. DR. G. H. FOWLER—BISCAYAN PLANKTON:

0°65 X 1:°32 = 0858; 0°86 x 1:32 =118; 1:18 xk 132= 1:49. This is as close as can

be expected in so small a species, where the unmeasured hundredths of a millimetre are

no doubt important.

It is obvious from the lengths recorded by Miiller (‘ Valdivia’ specimens, 2 1:1-1°65,

g 1:0-1:7) that Stage I., with a mean somewhere about 1:5 mm., was missing in the

Biscayan collections.

The actual measurements were as follows :—

oF mm, CE

0 13 1

29 1-2 3

peer a6 11 47 Stage IL.

16 10 21

46 0:9 81 Stage III.

Stage ITI. 3] 0-8 0

6 0°7 4

Stage IV. 99 06 82 Stage IV.

8 05

Stage V. 5 O04

Taste F.—Total specimens measured: 326 2 +239 ¢ =565.

It is quite possible that the larvee of less than 0°9 mm. include a few larvee of spinifera,

possibly also of procera.

Fig. D.

io) mim foal

CoNCH@CIA HADDONI, Brady & Norman.

The specimens available were very few, but at least four stages were recognisable

among the females, and two (I. and III.) among the males. The attribution of some

of the smallest specimens (0°7 to 0°4 mm.) was naturally not always assured, but the

high position of the right asymmetrical gland seemed to indicate this species.

THE OSTRACODA. 265

The specimens were thus distributed :—

OF mm. 3.

| 1 2:

Stage I. y 4 28

Mean, 2°72. | 3 27

6 2°6

1 25

21 2 Stage I.

Stage II. [2 ey

Mean, 1°66.\1 : 16

Stage III. -/1 11

Mean, 1-01. | 1-0 3 Stage IIT.

(1 08

Stage IV. l6 a,

Mean, 0°66. | 3 0°6

1 05

? Stage V. ?3 0-4.

Taste G.—Total specimens measured: 387+?73 9,5 ¢=42+73.

Jn the females the usual proportions between the means appear, the second place of

decimals being somewhat vague, presumably owing to the paucity of specimens. Thus,

0°62 x 1:64 = 1°01; 1:01 x 1°64 = 1656; 1:66 x 164= 2°72. The observed mean of

0°66 for Stage IV. is perhaps too high, and the growth-factor employed a little larger

than the true factor.

In the males, Stage II. with a mean length probably somewhere about 1°45, was not

represented in the collections.

CoNCH@CIA HYALOPHYLLUM, Claus.

Four stages were observed; of these only the second, or lower sexual stage, has

hitherto been recognised, except by Juday, who gives a length for females of 2°4 mm.

without further comment. The first stage was apparently described by Miller under

the specific name lophura.

The actual measurements were as follows :—

9. mm. de

. a! 25

Bee 23 1 Stage I.

Mean, 2°3. | o1 9:

| 8 My

Stage I]. | 24 16 3 | Stage II.

Mean, 1°58. } 13 15 27 paiean, 1°5,

L 2 1-4 3J

1 12

Stage IIT. | 8 i 7 \ Stage II.

Mean, 1:07. ] 5 1-0 1 { Mean, 1-08.

L 07 1 Stage 1V.

Taste H.—Total specimens measured: 62+71 9; 43 ¢ = 105.

266 Dk. G. H. FOWLER—BISCAYAN PLANKTON :

The ratios for Brooks’s law come out sufficiently clearly, although the total numbers

are small, and in spite of the difficulty of separating this species from magna * at the

lower stages.

Taking the means as a basis for calculation :

2 1:07 x 148 = 15859158 asi Ss:

6 077 X 1:40 = 1-078; 108 XA Abs 150 x 142-10:

Taking from fig. E the probable extremes of females at Stage II. as 1°3 and 1°8, we

get the probable extremes for Stage I. as 1:9 and 2°6; similarly taking the extremes for

males as 1:3 and 1°7, we arrive at 1°8 and 2°38 as the probable extremes for Stage I.

This by itself would throw doubt on Juday’s record of 29 for a male; besides which,

he notes only “about twenty pairs” of teeth as the armature of the principal bristle of

antenna I. As his brief description is not accompanied by figures, it is not apparent

what species was before him, but it was probably not hyalophyllum.

Fig. EK.

Q mm fol

24°20 (6 2 “8 4° (O00 4eesenle 6 20 24 28

CoNCHGCIA IMBRICATA (Brady pars), Miiller.

The actual measurements of this species have been given in the Introduction (p. 225)

and need not be repeated bere. As already mentioned, on the analogy of other species,

there can be little doubt that an older stage exists than any which has yet been recorded

with a probable mean length of about 2 3°65, ¢ 2°76. The measurements given by

Miller for this species seem to have included rostrum and spine.

* It is quite possible that some huyalophyllum at Stage III. have been placed with magna at Stage ILI.; it is

possible that some hyalophyllum Stage 1V. have been ranked as * A” larvae (compare p. 245).

— ca

THE OSTRACODA. 267

CoNCH@CIA INERMIS, Claus.

The three specimens captured consisted of two males, 1:9 and 1:5 mm.; and one

female, 2:0 mm. The smaller male had not developed secondary sexual characters

and was therefore presumably at Stage III.; in this case Stage I., with a male mean

presumably about 2'4 mm., has not yet been identified.

CONCHCIA LORICATA, Claus.

It is rather curious that the earlier stages of loricata should have been so rarely

recognized in the ‘ Research’ collections. It is unlikely that some specimens in which

the lateral glands were invisible or inconspicuous were included with Stage IL. of magna ;

a close re-investigation of very numerous specimens of the latter with this very object

failed to reveal more. As the specimens of adult ovicata in the comparable epiplankton

amounted only to 40, and those of magna Stage I. to 186, the penultimate stage of the

former is not likely to have been very numerous. On the other hand, if any specimens

of Stage IV. and earlier stages were captured, they have probably been put with the

“A” larvee.

The actual measurements were :—

Or mm. 3

‘cal 2:8

| 8 27

Stage I., | 19 26

Mean, 2°58. 1 10 25

| 1 ar x Stage I.

aL 2°3 2

7. 2 | Mean, 2°31.

) 21

Stage II.

Mean, 2:0 ei he

ine D 19 1)

18 1 \ Stage Il.

1:7 1 | Mean, 1:75.

16 ie,

Stage IIL., + ] re : | Stage Ill,

Mean, 1°3. 1 le ~ J Mean, 1:2.

Taste I.—Total specimens measured: 49 9 + 13 g = 62.

The specimens at Stage ILI. are too few to give satisfactory growth-factors.

SECOND SERIES.— ZOOLOGY, VOL’ X. 44

268 DR. G. H. FOWLER—BISCAYAN PLANKTON :

CoNCH@CIA MAGNA, Claus.

The actual measurements are as follows :—

OF mm. Ole

( 4 3°6

| 96 3°5

26 34.

Stage I. ie

20 33

Mean, 3°36. 9 3-9

3 31 3)

3 30 23 | Stage I.

29 15 | Mean, 2°91.

2:8 22 J

1 a9

Wave 21

40 2-0 27

Stage II. 5A 19 12 |

Mean, 1°88. 64 18 78 mee ee

16 igi AD:|. oo

| 5 16 7J

1 15

1:4 dy

(eee gh oP | Stage III.

Stage III. | 193 12 TSG Nica 1:08

Mean, 1'14. | 216 1 172.) web

eG 1:0 J

Taste J.—Total specimens measured: 754 9 + 417 6=1171.

Unusual features of this, the most plentiful species, are the flat-topped curve of

Stage I. in the females, and the double-humped curve of Stage I. in the males. These

features were consistently noticeable, when the observations were summarized from time

to time as the investigation proceeded, and appear to be genuine. There seem to be three

possible explanations of these abnormalities. The first (the most obvious) is that I have

confused together the successive stages of two parallel species with nearly identical

structure: this explanation does not commend itself to me (leaving out of count the

care taken over the work), because I do not believe that two such exactly similar species

can co-exist in such intimate association in the same locality; this explanation must,

however, be borne in mind. A second possibility is that the larger “ macrocheira”

forms may really belong to a different species from the smaller “magna” forms. This

would imply the very improbable result that of two closely-allied and intimately

associated species the one was represented only by Stage I.*, the other only by Stage II.

and perhaps smaller stages.

* The observations recorded in the Systematic Part seem to leave no doubt that the Halocypride have two

stages with secondary sexual characters.

THE OSTRACODA. 269

Against both the foregoing possibilities may also be urged the argument from constant

association. Of the 65 comparable hauls in the epiplankton, 48 contained what I term

Conchecia magna *. Of these 48 hauls, 81 per cent. contained at least two stages, and

45 per cent. contained all three ; the association was therefore very constant.

The third explanation—almost the same as the first, but in other words—is that the

species is unstable, is beginning to split up into a larger and a shorter race. So long as

a species is stable it seems probable that any character measured and plotted graphically

Fig. F.

2 ™m oo”

220 200 180 160 140 120 100 80 60 40 20 is} 20 40 60 60 100 §6120) ©6140 (so 160 200 220

Ne Oe Se Se! ee Sey Caen ae Snne Sae C Cn ne ner Seer Eee eee Wee

The two lower curves on the right hand of the abscissa are of both sexes of “ A” larve mixed.

will yield a curve of frequency with a marked mode; but if the species tends to vary in

respect of that character into two races, the curve will ultimately show a double hump

with a central depression between the two modes about which the measurements are

grouped; the depth of this depression has even been used as an “index of isolation.”

But before the two races have been so far established as to show the double-humped

curve, there will presumably be a transition period at which the curve, instead of

presenting a tall mode, will show a flattened apex, and this condition is apparently

* Of the remaining 17, 11 contained Halocyprids but not magna.

44.*

270 DR. G. H. FOWLER—BISCAYAN PLANKTON ;

represented in the female Stage I. of magna. Provisionally, therefore, I regard magna

as exhibiting an early phase of a tendency to split into two races.

When this investigation was begun, it was of course not realized at first to what the

measurements of the specimens by sexes would lead. Unfortunately therefore, owing

to the probability that one or two other species were included with magna in the

A larve (p. 245), and because my object was merely identification of species with a

view to questions of distribution, it did not at that time seem worth while to carry the

measurements lower than 1:0 mm., and not even all specimens of that length were carefully

recorded, as was the case with the greater lengths. It could not thus early be foreseen

that one was thus arbitrarily cutting off the shorter members of Stage III., with the

result that the mean calculated on the recorded specimens is necessarily too high. This

seems to be shown, at any rate in the females, by dividing downwards, instead of the

method of multiplying upwards adopted in other species. By dividing the mean for

Stage I. by that for Stage IL., 3°36+1:88=1-78 the growth-factor, and 1:88+1:°78=1:05

the probable mean for Stage III., whereas my mean is 1:14. As the meaning of the

double-humped curve of the males is obscure, one does not know how to handle

the figures of Stage I.; treated as in the females, the observed mean of Stage I. gives a

probable mean of 1:07 for Stage III., and the ordinate of the lower hump gives a

probable mean of 1:12.

it may be possible to sex and measure these smaller specimens later, but at the

moment it would delay publication for some months.

There are other features noticeable in these curves which I must leave to better

mathematicians than myself to explain.

THe A LARVz.

Only about a quarter of these larvee were measured, for the reasons already given.

They yielded 25 at 0°9 mm., 209 at 0°8, 76 at 0:7, 59 at 0°5, 3 at 0'4 mm. The absence

of any specimens at 0°6 seems to cut off those at 0-9, 0°8, and 0'7 as Stage IV., at 0°5

and 0'4.as Stage V. Those at Stage IV. form a good curve of frequency (plotted on the

diagram for magna), but any difference which may exist between males and females at

this stage is of course obscured.

A few specimens of Stage IV. were sexed and measured to a second place of decimals; but against

this is not only the uncertainty of the specific determination, but the difficulty of absolute determination

of the sex. In some specimens the rudiment of the penis is unmistakable, m others its absence ; but in

a large number one could not trust one’s own decision. So far as it went, the measurement seemed to

show a mean of 0:79 for females and of 0°83 for males, which may or may not have been true,

CoNCHGCIA PROCERA, Miiller.

As already mentioned (p. 246), Stage I. appears to be lacking in the ‘ Research’

collections, and is perhaps the form named decipiens by Miiller.

The iollowing numbers were observed :—

THE OSTRACODA. 271

2. mm, 3.

1 13

Suns 39 1:2 6 | Stage II.

fo)

Ee: | 27 11 35 S Mean, 1°11.

10 4

Stage III. [ 8 0:9 Stage III.

Mean, 0°9. ils 0:8 Mean, 0°9.

Stage IV. 4 07 2 } Stage IV.

Mean, 0°64. 5) 0°6 1J Mean, 0°66.

? Stage V. 1 0°

Taste K.—Total specimens measured: 85 2? + 62g = 147.

Taking the females first :—0°64 x 1°36 = 0°87; 0°871:36 =1:18. On morphological

grounds the specimen at 0°5 appeared to belong to an earlier stage than those at 0°6

and 0°7; and by the same growth-factor this stage would have a mean at 0:47. Further,

1:18 x 1°36=1°60, which is the (maximum observed) length given by Miiller for female

decipiens. _

In the males there is an overlap of the Stages II. and III. at 1:0, such as has been

actually observed in some of the smaller species dealt with in this memoir. Two of the

Fig. G.

2 mm (og

four specimens of 1:0 mm. belonged to Stage II., and two to Stage III. We thus get the

means given in the foregoing table; the numbers are (as usual !) too small for accuracy :

0°7 X1:26=0°88; 0°88X1:26=1:10. As regards decipiens, Miiller gives a (maximum

observed) length of 1:3 mm. for the male of this species, and 1:10 x 1:26=1°38.

272 DR. G. H. FOWLER—BISCAYAN PLANKTON:

CONCHGCIA PUSILLA, Miiller, var. Magor, Miiller.

The lengths observed were :—

2 mm. 3d.

1 0°8 1

O07 3

1 0:6

Taste L.—Total specimens measured: 2 9? +4 ¢=6.

It may prove to be the case that var. minor is only Stage IT. of var. major.

CONCHGCIA RHYNCHENA, Miiller.

As only one stage with secondary sexual characters in the male was observed (the

length of which agreed with Miiller’s rhynchena), the presumption is that an older stage

exists, possibly to be found in sampta or tyloda, as being the only suitable forms of the

mollis group captured during the cruise. My specimens of these were too few to

determine the point.

Measurement of rhynchena proper gave the following result :—

é.

wwvnwvwnw

wowek ag

Stage IT. |

Mean, 2°47.

i oe UL.

1J Mean 2°28.

MS : }s III

a age III.

Stage 1. | ne :

Mean, 1°60. | ~ se

1 15

F a T

Stage LV. : i 1 Stage IV.

Mean, 1:04.

1 0-9

Stage V. [ : te

Mean, 0:70. ] ‘

L2 0-6

Taste M.—Total specimens measured: 28 9 +11 ¢ = 39.

In the females the reaction to a growth-factor is very close :—

0°7X1:'54=1:07 ; 1:04 (mean) X1°54=1°60; 1:60 154=2°46.

As there are only three males to represent Stages III. and IV., it is useless to discuss.

their growth-factor, and the numbers in both sexes are too small for the contour of the

curves to have any value. They have therefore not been reproduced.

The separation between Stages IV. and V. in females is made on morphological, not

statistical grounds.

—

THE OSTRACODA. 273

CoNCH@CIA ROTUNDATA, Miller.

This species is so small that my comparatively rough measurements, to the tenth of a

millimetre only, fail to bring out clearly the successive stages. Between the lengths

of 0'4 and 1:0 mm. there are (apparently) four stages, or three moults within a range

of 0°6 mm., and it is obvious that a finer method is required, which was not foreseen at

the beginning of the investigation. It is probable, however, that even if measurement

to the second place of decimals had been attempted, an overlap of the highest and

lowest extremes of successive curves would have occurred (compare the case of curta,

pp. 260-1).

Fig. H.

The left-hand figure summarises the actual observations ; in the right-hand figure an attempt has been made to

resolve those ordinates which are due to the overlapping of curves (p. 274).

It is fairly obvious from the diagram that there are four stages on the female side of

the scale with maxima at (+) 0-4, 0°6, 0°8, 1:1. Similarly, anatomical investigation

showed that the amorphous curve on the male side was really soluble about four maxima

at (+) 0°4, 0°6, 0°8, 1:0; the divisions (moults) coming somewhere near 0°45, 0°7, 0°85.

The high ordinate at 0-7 on the male side is therefore apparently due to the sum of

larger specimens of Stage III., and smaller specimens of Stage II. (lower sexual stage) ;

unfortunately no record was kept of the numbers of these two stages at this length,

as the outcome of the investigation was not foreseen at the time. Consequently, only

274. DR. G. H. FOWLER—BISCAYAN PLANKTON:

prolonged study would show how this and similar ordinates are to be divided between

the two stages of which they are the sum.

The actual measurements were :—

Or mm. d.

3 Lie, 0)

8 1 2

3 10 3

9 0-9 5

93 0:8 40

27 07 43

41 0-6 41

13 05 5

31 O'4 7

4 0:3 0)

Taste N.—Total specimens measured: 232 2? + 146 ¢ = 378.

There is a rough way of dealing with these curves, which would probably not commend itself to the

statistician: namely, to divide up the doubtful ordinates proportionately to the apparent modes above

and below them, on the quite unsupported hypothesis that the lengths of the minor ordinates of the

curves vary with their modes. Thus, for example, in the females, the modal ordinate at 0°8 is made of

93 specimens, that at 0°6 of 41 specimens, and 93: 41::2°2:1; consequently the doubtful ordinate

of 27 specimens at 0:7 has been divided as 18°5 specimens to the upper curve, and 8°5 to the lower.

Similarly, the modal ordinate at 0°6 is made of 41 specimens, and that at 0°4 of 31 specimens ; and

roughly 41:31::4:3; consequently the doubtful ordinate at 0°5 has been divided as 7°5 specimens

to the upper curve, and 5°5 to the lower. In this way have been obtained the ‘‘ pecked” curves on the

right-hand side of figure H, which represent a possible extent of the overlapping.

From the allotment of the doubtful ordinates on these lines came out the following means:—Females

at Stage I. 1:11; Stage IT. 0:79; Stage III. 0°60; Stage IV. 0°40. Males at Stage I. 1:0; Stage II.

0°77; Stage III. 0°61; Stage 1V. 0°41. Now 0°42x1:39=0'58 (0°6); 0°58x1:39=0'8 (0°79) ;

0:3X1:39=1'11: and 0°47x13=0°61; 0-61x13=0°79 (0:77); 0°779x1:3=1°02. This isitainy

good, considering the all-round possibilities of small errors.

It does not seem possible to get a closer result, without a more refined system of

measurement, which, as already pointed out (p. 260), has its own peculiar difficulties.

Rotundata is so far a more favourable object of study than curta, in that its shells are

more flattened laterally, and can therefore be much more easily poised in a true profile

position

CONCH@CIA SPINIFERA, Claus.

Only three stages were observed, of which only one showed the male with secondary

sexual characters.

The following measurements were made :—

See

THE OSTRACODA. 275

ig mm. 3.

(Cal 2:3

Stage IT. | 12 22

Mean, 2°12. | 17 21

L 4 20 1)

1:0) te 2 stage 1a

18 9 | Mean, 1:80.

17 4J

Stage ILI. { 8 15 2) Stage ILI.

Mean, 1°44. L12 1-4 11) Mean, 1:41.

Teil 1) Stage IV.

Stage LV. 4 1-0 2J Mean, 1:08.

Mean, 0:98. L 1 0-9

Taste O.—Total specimens measured: 59 ? + 82 ¢ =91.

Fig. I.

9 mm or

15 10 loF 1S" 20

The females, although few, respond well to Brooks’s law :—0°98 x l47=1-44;

1-44 1:47=2°11. There were only three males at Stage IV., a number which cannot

be expected to yield a satisfactory mean; the mean is too low to fit with the ratios

between Stages IIT. and II,: 1:08x130=1:40; 140x130=1°82.

If the supposition that an older stage exists be correct, its female mean will be about

3°10=2°11 1°47, and its male mean about 2°36=1°82 x 1°30.

SECOND SERIES.—ZOOLOGY, VOL. X. 45

276 DR. G. H. FOWLER--BISCAYAN PLANKTON:

CONCH@CIA SPINIROSTRIS, Claus.

=C. porrecta, Claus.

The table of measurements given below seems to show two male and two female

stages. Both of the male stages exhibited secondary sexual characters, the longer

having more teeth on the armature-than the shorter; they may safely be placed as

Stages I. and II. But according to the rule which seems to hold good in almost all the

groups of Conchecia (the curta-group excepted, where the males are said to be of the

same length as, or even a little longer than, the females), the females at Stages I. and II.

are longer than the corresponding males; the presumption therefore is that the females

belong to Stages II. and III.

Dr. Miller gives porrecta Claus as a synonym for spinirostris (ich halte C. porrecta

Claus, nur fiir gestreckte Individuen von C. spinirostris”), With this I agree, with the

slight correction that I hold porrecta as the Stage I. of which spinirostris is the Stage II.

Of the two names the latter has priority.

As regards the lengths, Claus gives 16 mm. without specifying the sex; Miller

records 1:1-1°6 for females *, 0°95—-1'4 for males. The range between these two extremes

is rather large for so small a species, and he probably had both stages before him.

The lengths represented were :-—

OF mm, Crs

9 | Stage I.

13 “

Mean, 1:3.

2 12

Stage II. : 8 11

Mean, 1°10. 1 1-0 3) Stage II.

0-9 5 J Mean, 0°93.

Stage II. i 08

Mean, 0°75. L? 1 07

Tasie P.—Total specimens measured: 13 9 +10¢ = 28.

As regards the relation with porrecta—in the females 0°75 x 1'46=1:09; 1:09 1-46

=1'59, which is just within the range observed by Muller; the two males at 13 are

also within his limits.

Miiller has described and figured (Naples Monograph, p. 183, pl. xxxiv. figs. 1, 2, 3, 5)

four young stages of this species, of which the two older at least were males; all are

younger than the ‘ Research’ specimens. Measured without the rostrum, they were 0°33,

0:44, 0°59, 0°79 mm. Now 0°338x1°35=0-44; 0°44 1'35=0°589 (0°59); 0589 X135=

0:79; these are therefore related as in other species. As already pointed out (pp. 227-8),

it is not likely that the rates of growth will be exactly identical in different sea-climates,

but my male means (on only ten specimens) yield a growth-factor of 1:39, which is not

very far off the other; the two sets of observations only just fail to fit together, the

* Vigure measured without rostrum, 1°5 mm.

THE OSTRACODA. 277

Biscayan means being just too short for a continuation of the Mediterranean means.

The two sets of observations give six stages at least for this species,

CoNCH@CIA ZETESIOS, Sp. N.

Only two stages were observed, both of which were female. Their measurements

were :—

@) mm,

(ea 26

Stage ?I. | 7 2°5

Mean, 2-42. 5 24

1 5 23

Stage ?II. I 9 15

Mean, 1°5.

Taste Q.—Total specimens measured: 20 2.

HatocypPris GLoBosa, Claus.

As regards the males, the lengths of my single specimen (2°1 mm.) and of Dr. Miiller’s

(2°25 mm.) seem to indicate that they belong to the oldest stage, if compared with the

mean of females at Stage I.

The largest females of the ‘ Research’ collections (2°1 to 2‘8 mm.) were slightly smaller

than those recorded by Miiller from the ‘ Valdivia’ expedition (2°6 to 3:0 mm.); but

45*

278 DR. G. H. FOWLER-—BISCAYAN PLANKTON :

their curve (fig. J) shows that they all belonged to one stage. At least four, probably

five, stages in all were represented.

The actual observations were as follows :—

Oye mm.

( 6 2:8

| 12 2-7

| 107 26

Stage I. 83 2:5

Mean, =.) 22 2°4

22 23

| 8 2-9

2 21

( 6 12%

13 16

Stage II. | I 15

Mean, 1°54, 8 1:4

| il 1:3

Legal 1:2

Stage III. 4 1:0

Mean, 0°95. 4 0:9

Stage IV. 2 0-7

Mean, 0°61. 9 06

Stage V. { 1 0-4.

Mean, 0°40.

Taste R.—Total specimens measured: 315 ? +1 ¢ = 316.

Stage I. shows a solid, but markedly asymmetrical curve, if the ordinates are simply

joined up. Stage II., on the other hand, shows a double-humped curve (for which no

morphological reason appeared), and the lower part of the curve of Stage I. could

without violence be resolved into a double hump. It is conceivably possible that these

abnormalities in the curves may be connected with the rarity of males, if there is any

truth in the suggestion on p. 308 that parthenogenesis may occur in this species, since a

parthenogenetically produced race often differs markedly in structure and size from

a sexually produced race.

Considering the scarcity of the smaller specimens, the response of the mean to Brooks's

law is good: —0'37 X 162=0°59; 0°59 X 1:62=0°95 ; 0°95 X162=1'539; 1:54 x162=2-49.

The preponderance of Stage I. over the earlier stages is unusual, but the same was

shown by imbricata.

Owing to the few observations at Stages III., IV., and V., only the two oldest can

safely be tested for the extremes of the curve ; and respond well :—2‘$+1:62=1°7 ;

2°1+1:62=1°2.

THE OSTRACODA. 279

ARCHICONCH@CIA CUCULLATA, Brady.

Judged by a measurement of his figure, Dr. Miller appears here, as elsewhere, to

have included the rostrum and posterior spine in his measurements :— @ 1-85-2°2,

g 1:8-2:2 mm. The measurable male of my two specimens (327) was only 15 mm.

by my method, 1:9 with the rostrum, 2°1 with the rostrum and spine; it fell, therefore,

into the same stage as Miller’s specimens. ‘The two females measured 1:0 mm. by

my method (1-4 with the rostrum and spine), and belonged therefore to an earlier

stage, II. or IIT.

CYPRIDINID.

CYPRIDINA CASTANEA, Brady.

Apparently three stages, I., II., and IV., were represented in the five specimens ;

with a growth-factor of 1:5, the lengths 1:8, 2°7 (missing), 4°0, and 6:0 are related as in

the other species.

Herrick’s Records of Homarus americanus.

It will, I hope, be apparent to the reader that the species just enumerated do respond,

however imperfectly, to Brooks’s law. In Herrick’s great work on the American

Lobster (Bull. U.S. Fish Commission for 1895) are given records which enable us to

test it in another group of Crustacea. For this purpose his “‘ Record of moults of larval

and adolescent stages ” (table 34, pp. 176-177) is the most significant. The first three

columns in the following table are taken from this record; the fourth column shows

the product of the mean length at each moult xa growth-factor 114, which is in every

case remarkably close to the next highest observed mean length.

Mou cette 2

TAT ch Sse iss 3 8:0 91

ATT See On eete rate 8 9°1 10°3

Nae he 1 26 10°8 12°3

AMR stent thins 28 126 143

Lh» Lan egnerReheeneee 20 14-4 16°4

GUmEr nana tccsice 12 161 18:3

Vi ial 5S ts cee A 18°6 21:2

I aed cod 5 211 24-0

OW a ES Riau 2 24°5 27°9

eee ennennaeee 3 28:0

GE a 111

It is quite evident that the same relation exists in the early stages of Homarus

americanus as in the Halocypridee. The actual ratio is much lower in the lobster than

280 DR. G. H. FOWLER—BISCAYAN PLANKTON :

in the Ostracods, but it seems likely that the larger and the longer-lived an animal,

the less will be its increase at each moult. It is also probable that (as has been shown

in some other marine forms) the rate of growth will not be by any means necessarily

the same under laboratory conditions as in a state of nature.

The data in table 34 are included with others in Herrick’s table 25 (p. 97), where

1°15 fits better as a growth-factor than 1:14; but even this only contains 246 specimens

spread over ten moults.

In table 28 (p. 99) Herrick gives the sizes of various parts of the skeleton before, and

five days after,a moult; the detailed figures need not be printed here, but show—

what, indeed, we knew already—that different parts have each their own growth-rate.

In dealing with a large form like the lobster, a distinction must be drawn between

growth-moults at the young stages, and the moults at the later stages. If a lobster

continued to moult at the same brief intervals, and to grow by the same increment as

did Herrick’s larvee, it would be 103 inches long at the end of its first year (instead

of 2-3 inches), and in five years would be a dangerous monster of portentous size.

We know, as a matter of aquarium observation, that the number of moults per annum

and the increment at each moult diminish with age. Unfortunately Herrick’s obser-

vations do not help us to trace this decrease. It is not easy to measure accurately

anything so flexible as a many-jointed lobster, especially after moulting, when the

connecting membranes have been stretched and the skeleton has been torn across the

middle *. This, however, would probably not matter so much if the observations were

numerous instead of being scanty and scattered. Hence it is not surprising that the

observation in Herrick’s tables 20 (82 observations for 14 inches), 32 and 33 (63 obser-

vations for 100 mm.), when plotted, failed to show definite groups round medians from

which the growth-rate of older stages might be safely inferred.

Records of Carcinus mezenas.

Dr. W. T. Calman was good enough to call my attention to a paper t which contained

measurements of this species by Mr. H. J. Waddington and the late George Brook,

and to place at my disposal some of Mr. Waddington’s actual specimens. The latter

gentleman measured (apparently not more closely as a rule than 0:25 mm.) the greatest

breadth of the cast shells of eleven individuals which he had kept in aquaria. The

total observations were only 117, to cover a range in growth of 0°9-62 mm., but seemed

to be worth study. When plotted on scale-paper, the observed breadths seemed, at

some parts of the scale, to fall into groups round obscure medians; for example, at

9-10, 12-14, 15-17, 18-21 mm. By following out these indications and by working

in both directions from them, the following table was obtained. On the immediate

left of the vertical line are the means of these vaguely indicated groups; on the right

* It would be safer to measure the live lobster between moults, rather than the cast skin; and in every case

to measure also the cephalothorax to the root of the rostrum as well as the total length, carefully noting the sex.

Tt H.C. Williamson: “Larval and Early Young Stages and Rate of Growth of the Shore-Crab,” Ann. Rep.

Fishery Board Scotland, xxi. pt. iii. p, 136,

THE OSTRACODA. 281

of the line are the successive products, by an empirically-found growth-factor, of means

starting from 4°80, the lowest observed mean of the series *.

Mean of 5 specimens of +5mm.= 4°80 4°80 x 1:27 = 6:09

is Deas oA arg 6°05 6:09"; 7-73

F Somes, i a8) |; 775 CGO 5, 9°81

Pk airs Sing 210 |: eveiae 981 ,, 12°45

ree a ae 12-14 .,, “1eGa Weds |, 15-81

BA) OBR opt » 15-17 ,, 1602 | 15°81 1:23 = 19-44

ee: ee i 18-21. ,, EQsOuN 1944 ,, 23:91

i ei » 22-26 ,, 23:39 | 2391 , 29:40

a SP aires » 28-33 ,, 29°80 29°40

The close approximation of the two sets of means—those which seemed to come out

of Mr. Waddington’s observations, and those got by multiplication with a growth-

factor—seems to show that the inferred grouping was approximately correct, and that

numerous and delicate measurements would show the validity of Brooks’s law at the

earlier stages. The drop in the growth-factor is interesting, if genuine.

But while the species as a whole thus seems to fall into general line with the

observations on Ostracods, the individual specimen (as was also noticed in the American

Lobster) does not seem to follow the law with mathematical exactness at each moult.

An individual of, say, the mean breadth at a particular stage will not necessarily be of

the mean breadth of the subsequent stage; it may be either broader or narrower, so

long as it keeps within the extreme limits for that stage. In Mr. Waddington’s

observations the actual increment at a moult (=the broader + the narrower) varies a

good deal in some cases. ‘To some extent this may be due to variations in the aquarium

conditions: a large part is probably due to the specimens having been dried before

measurement +; part may be set down to the method of measurement (compass and

seale, not micrometer-microscope); but a part is probably the animal’s own “ error.”

A most interesting piece of work awaits anyone who will take up the whole question

on large Crustacea, with refined systems of measurements of wet specimens. On the

whole, a form in which the total length was easily measurable would probably be more

reliable than a Brachyuran, in which the breadth of the cephalothorax might possibly

be influenced by the necessity for housing a rapidly increasing generative organ at a

certain stage.

General Course of the Development of Halocypridie.

It will have been obvious to those who have followed the descriptions in the

Systematic Part, that the morphological changes in the successive moults proceed along

fairly well-marked and similar lines in all the species. It is too early as yet to lay

* Below 5 mm, the observations are numerous, but the measurements not delicate enough to separate the various

groups ; above 33 mm. the observations are few and widely scattered.

+ Re-measurement of some of Mr, Waddington’s series in the British Museum seemed to show that they had

shrunk eyen since he measured them.

282 DR. G. H. FOWLER—BISCAYAN PLANKTON:

these down precisely, still less can we yet deduce the ancestral form of Conchacia; but

they may be outlined as follows:—The shell of the earliest larvee is very high in

comparison to its length, and a steady unbroken curve runs from the postero-dorsal

angle to the antennal recess: figure 166 shows a typical early larva. The frontal organ

is at first straight, unsegmented, spineless, transparent, and thin-walled; its apex may

be either rounded or acute. The first antenna exhibits one bristle and four tubes, even

in the younger males. The inner joint of the second antenna has neither central nor

basal bristles. No distinction seems to be at first possible between males and females ;

later, the penis grows out as two rudimentary papille, and the three bristles are

differentiated from the two tubes in the male antenna i.

As development proceeds the shell becomes (as a rule) longer, but only attains the

adult contour gradually, through a succession of moults. The shell of the adult

female in the later stages tends to be fuller posteriorly than in the male (that is to say,

to project further behind a perpendicular dropped from the postero-dorsal angle), and

to have its highest point behind the middle of the length; the shell of the male,

speaking generally, has a straighter posterior border. The frontal organ assumes the

adult type, if this be highly specialised, by passing through forms which are fairly

constant for each stage, but are often highly different from those before and after

them. ‘The frontal organ of the adult female is sometimes of a larval type (spinirostris);

it is rarely so highly differentiated as in the male, but this is sometimes the case

(haddoni) ; asa rule it is intermediate in complexity between larval and male types.

The principal bristle of antenna i. in the male has at first the sparse irregular minute

teeth which are typical of the adult female; it does not assume the definitive secondary

male characters (length and armature) until the penultimate Stage II. The dorsal

bristle of antenna i. in the female is of comparatively late appearance (generally at

Stage IT. or PIII.). The inner joint of antenna ii. assumes at first one or two central

bristles, later on it may develop basal bristles; the latter may even occur in some

females (haddoni). The hooks of the male antenna ii. are not developed till Stage II.

IV. FAUNISTIC PART.

Many reports on the various collections made by recent expeditions take for granted

that a specimen, merely because it was captured in a closing-net, was necessarily living

in the zone explored by the net. This reasoning appears to me most fallacious. When

we remember that the abyssal benthos is almost entirely dependent for its food-supply

upon the unceasing rain of dead organisms from the upper horizons, it becomes obvious

that, always and everywhere in the mid-water, there must be organisms which are dead

or dying and sinking to the bottom to furnish this food. Consequently, very strong

evidence should be forthcoming, before a species which is plentiful at or near the

surface is admitted to be living also in the mesoplankton of its immediate district.

This evidence (apart from the specimen being actually observed to be alive when

brought on board, which is very unusual in a haul at great depths) can only consist in its

being captured often and in considerable numbers from the mid-water. In few cases,

THE OSTRACODA. 283

indeed, has such evidence heen brought forward. The presumption is always against an

animal living under two such totally opposed environments as the epiplankton and

deeper mesoplankton, until the contrary has been shown to be probable. Such cases are

believed to exist, and three are given below in which apparently the younger stages

are epiplanktonic, the older mesoplanktonic; but they are comparatively rare.

Nor can the condition of the tissues be admitted as evidence :—Firstly, because the

tissues of indisputably mesoplanktonic animals are sometimes damaged, either by the

diminished pressure, or by the chafing together of the sides of a closed net, when being

hauled. Secondly, because salt water in bulk at low temperatures is an excellent

preservative, and at great depths bacteria are few; the tissues may apparently remain

unaltered for a long time after death *.

Brandt and Ostwald have shown how little is the difference between the specific

gravities of an organism and of the water, which determines whether an animal floats

or sinks; from this it would seem to follow that, as soon as an organism is sickly enough

to be unable any longer to keep up the fight against gravity, it will begin to sink,

although by no means necessarily dead. The only evidence available, therefore, at

present is from the comparative abundance or scarcity of the species at different depths.

Hence, when an animal is plentiful in the epiplankton, and shows fairly high averages

in the upper mesoplankton, but below that shows only fractional averages per 100

fathoms, it is assumed in the following pages that these fractional averages represent

only dead or dying specimens sinking towards the bottom. It is not the actual

numerical value of the average that is here significant,—for many of the rarer meso-

planktonic forms show equally small averages,—but the ratio of this average to those

obtained at higher levels. As an example may be taken the sudden drop in the averages

for curta (young stages) below 250-150 fathoms, when compared with the figures for

200-100 and 150-50 fathoms, a drop which is maintained fairly steadily down to

1250-1000 fathoms (p. 284, Pl. 27).

In this part of the memoir, except where otherwise mentioned, all numbers of epi-

plankton specimens have been treated with the usual time-factors to bring them as far

as possible to the standard one hour haul.

HALOCYPRID&.

ConcH@CIA AMETRA, Miiller.

This species was obviously mesoplanktonic; it occurred at the following depths

only :—

Between 400-300 fathoms in 1 of 3 hauls, with 0°66) ppacumenh pes

oH got ad oo ae 2 cal 100 fathom

a 750-500 “ ee FS 0-80 |

A 1000-750 in Mes, AD i 0:08

* H.N. Moseley: Notes by a Naturalist on H.M.S. ‘ Challenger,’ Ed. 1892, p. 505,

SECOND SERIES. —ZOOLOGY, VOL, xX, 16

284 DR. G. H. FOWLER—BISCAYAN PLANKTON:

CoNCHGCIA BRACHYASKOS, Miller.

This appears to have been another deep-water form ; it occurred only :—

Between 300-200 fathoms in 1 of 3 hauls, with 0:33)

average

» 500-400 Male 6) oe ooh ee OE

specimens per

» 750-500 oa Se FS

» 1000-750 7 SS nails HOLL ORR, ae

| ERLBOOLASEO (0%, ccn0, 1S RmaeRnNCO:40 J

ConcHa@ctra curTA, Lubbock.

The following table, in three parts, gives the distribution (1) in the epiplankton in the

usual manner; (2) of “small’’ specimens, at 0°8 mm. or less, in the mesoplankton ; and

(3) of large specimens, at Stage I. of 0°9 mm. or more, in the mesoplankton :—

At 0 >) ( 38 percent.of 13hauls, with 4:1 )

25 li cdathoms=9)/| 683i MMe 5 849) |. y 2Nclage

50 r this species 1 69 f 13 a 11-3 + Specimens

75 | occurred in | 80 Pr 10 a 61:3 | per hour

100 J OR ee Tr 79 J haul.

Between 150-50 ¢ 1 out Or 35 7:0

200-100 | | 3 “3 7 % 3:8 )

250-150 3. aoe emai % 2-6 |

300-200 | fathoms young | 1 ” 3 4 0-6 |

400-300 a specimens 1 » 3 ” 0-3 average

500-400 | occurred in 2 ” 3 ” 13 | specimens per

750-500 3 of 4 nA 1:8 . 100 fathom

1000-750 9) eal, - 0-1 | ee

1250-1000 J C2 eS a5 01

Between 500-400 7 eae Gras 1 I 3 # 06 |

750-500 Ns 33 ip 4. oe 15

Stage I.

1000-750 oat tl eames as 5 » 04

/ , occurred in

1250-1000 } are, » 01 )

From this table may be inferred :—(1) That the numerical centre of distribution of the

smaller specimens was in the lower part of the epiplankton. Taking the percentage of

hauls in which the species occurred as well as the average specimens per hour haul *,

one may say that the centre was between 25 and 75 fathoms, probably nearer to 75 than

25. This conclusion is for the whole twenty-four hours, neglecting day and night. The

night hauls are analysed below (pp. 285, 303). (2) That the large specimens (0-9 mm, or

more), which were only taken below 400 fathoms, were probably at home at those

depths, like the larger specimens of votwndata. (3) That it is to be noted that there was

a very sharp drop in the numbers of small specimens per 100 fathom haul somewhere

* The high values for the total catches at 25 and 75 fathoms, when that at 50 fathoms was comparatively small,

have been noted in some other cases. Here the high figure at 25 fathoms is due to two late evening hauls, of 126

and 155 specimens ; the remaining ten hauls only produced in all 138 specimens. Compare pp. 302, 303,

THE OSTRACODA. 285

about 200 fathoms; taking this in combination with (2), I infer that these smaller

specimens below 200 fathoms were either dead, dying, or sinking to complete their

last moult to Stage I.

Further, it would seem that, though a few specimens occurred as high as the surface

and throughout the epiplankton by day, 4.0 a.m—7.0 P.M., yet the majority of specimens

lived below 100 fathoms, and only rose into the epiplankton by night, 7.0 P.w—4.0 a.m.

Analysis of the upper hauls yielded the following result ;—

At 0 fathoms the average catch per hour was 6:0 by day, 12 by night.

25 os eo fs OS 696,

50 sy » a B00 4, Let rf

75 ” 2 > 15°3 ») 81-0 »”

100 » te At, 12:2 3

And, without insisting too strongly on the individaul figures, there can be little doubt

that, taken as a whole, they show a far greater population by night than by day.

In summary, it appears probable that the younger stages were essentially of the

epiplankton and upper mesoplankton between 0 and 200 fathoms, with a night centre of

distribution at 25-75 fathoms; but the older stages were purely mesoplanktonic *,

with a maximum between 750-500 fathoms.

The curious rise in the number of small specimens between 400-750 fathoms will be

discussed later (p. 297). The whole distribution is very like that of rotwndata (p. 298).

The specimens at or near the surface were too few and too inconstant to afford any

evidence for or against reaction to rain, Xe.

CONCH@CIA DAPHNOIDES, Claus.

At 0 ry ( 0 per cent. of 13 hauls, with 0:0 )

ts | ire ra ae average

9 » c ” wt specimens

50 23 ; 13 11°8 r

ie ra ’ ” per hour

75 50 » 10 » gel haul

100 | | 35 ¥ 17 rn 1-0 J pets

Between 200-100 | fathoms 0 out of 7 i 0-0 >

250-150 t this species 0 a5 3 a 0-0

300-200 | occurred in | 2 ” 3 » 0°6 average

400-300 | 2 » 3 ” 23 specimens

500-400 | | 2 ” 3 » 20 per 100

ly 4 } é SU MN

750 ao | i : sa 0°38 | fathom haul.

1000-750 eit as a oF

1250-1000 | Ci ee Shs 0-0 |

1500-1250 } ee

The distribution presents some curious features. In the first place, all the epiplankton

captures were at night, except for a single specimen from 100 fathoms at mid-day.

* Of course if an adult lives at great depths, young specimens probably can also exist there, but it does not

follow that they do so,

4G*

286 DR. G. H. FOWLER—BISCAYAN PLANKTON :

Secondly, of the 285 specimens actually captured, no less than 65 per cent. were taken

in two hauls on a single night (30 /, 31 0, 50 fms.), forming a veritable swarm. ‘The

remaining epiplankton specimens were scattered fairly evenly over the night hauls—in

5 out of 7 night hauls at 75 fathoms, in 6 out of 8 night hauls at 100 fathoms. ‘Thirdly,

the steady occurrences between 1000 and 200 fathoms seem to point to the species being

mesoplanktonic, although it was missed altogether between 200 and 100 fathoms; but,

except for the two hauls already mentioned, it was nowhere so plentiful nor so regularly

captured in the epiplankton as that one should expect to find numerous corpses in deep

water.

In short, daphnoides was in the epiplankton practically by night only, was missed

between 250 and 100 fathoms, and reappeared between 1000 and 300 fathoms. It seems

almost inconceivable that the upper specimens at night retired to 300 fathoms by day

and returned in the evening: muscular effort seems inadequate, and we do not know to

what extent and by what methods a Crustacean can alter its specific gravity. A possible

clue is given by the fact that of the 235 specimens captured all were at the oldest stage

except one single one: this implies that breeding had not taken place in that water for

some time past; it is conceivable that a mass of the specimens had risen to breed, in the

way suggested by Chun and others for certain groups. But the species was nowhere

plentiful in the mesoplankton, and may simply have been missed in the hauls between

250 and 100 fathoms, in the ordinary run of chances, since each haul only filtered

theoretically 11-12 cubic feet of water.

CONCHGCIA ELEGANS, Sars.

, ith O°

At 0 ) ( Oper cent. of 13 hauls, with 0:00 ) ee

25 | 2s » 12 » 0-75 | specimens

50 | 46 » 13 » gs + a hour

75 | | 50 » 10 » Bot ; haul

100 | 52 ” 17 ” 464 )

| fathoms

Between 200-100 this species 4 4 out of if » 0°85 |

250-150 occurred in 3 » 5 B2 pee

z average

300-200 | 1 » oY 22 a | specimens per

400-300 Loe Bia \yns 088 1 Ta

‘+ 100 fathom

500-400 Le Ps Sig ia O28 haul

750-500 2s OE pay

1000-750 ee 9 5 » a)

Of the 582 specimens actually captured in the epiplankton (or 540 when treated with

the time-factors) only two specimens were taken in daylight. This seems to show that

the species as a whole rises by night and sinks by day. But it does not appear that it

extends to such depths as do some species; judged by the “average specimens per 100

fathom haul” of the foregoing table, one would not infer that it was living deeper than

300 fathoms, and 250 fathoms is probably nearer the mark.

As with daphnoides, the majority of the specimens came from two hauls at the same

depth on one night: but they were two nights later than the big hauls of daphnoides,

THE OSTRACODA. 287

25 fathoms lower, and something like fifteen minutes of latitude away; the actual

numbers were 193 specimens from 32 m, and 154 from 320, making about 55 per

centum of the total specimens of this species captured.

ConcH@ciA HADDONI, Brady & Norman.

At oy ( Oper cent. of 13 hauls with 0:00 )

z ; eee average

25 | fathoms | 16 _ 12 eS 0°33 eee

2 imens

50 ¢ this species els - 13 BY 0:69 L E

on | : | per hour

75 | occurred in 50 5 10 * 1:50 | ae

100 lL 35 = 17 wi 0:70 :

A single specimen also occurred at midnight at the surface in a non-comparable haul,

and other single specimens between 350-0 and 1250-0 fathoms. It was not captured

once in a closing-net. The species was obviously epiplanktonic, with a centre at about

75 fathoms.

CoNCH@CIA HYALOPHYLLUM, Claus.

As already mentioned (p. 266 note), it is possible that some specimens of this species

have been placed under magna. The numbers of occurrences and actual numbers of

specimens captured may therefore perhaps be too small, but they are probably correct in

proportion for the various depths.

At *0O B ( 7 per cent. of 13 hauls, with 0°30 ) .

| average

25 Se 1a 3 . 0:08

‘2 Rok specimens

50 7 » 13 ” O16 per hour

75 10). |e 1 | 210 aoe

100 29 es 17 ms 2°29 :

Between 200-100 pacliOms | 1 ‘cubes Gen O52)

DEEL (a Mont 2 aleallil Allis aero a... 088

300-200 To | 1 » 3 » 0°66 average

400-300 | 0 » 3 » 0:00 t specimens per

500-400 | [de 3 4, 0°66 [ 100 fathom

750-500 3 Fe 4 » 0°60 haul.

1000-750 g oe LA G88

1250-1000 1 F ie poe OS

The recorded specimens are by no means numerous at any depth, but they are widely

and almost consistently distributed vertically, down to the zone 1250-1000 fathoms.

They are too scarce in the upper strata for the idea that the mesoplanktonic specimens

were merely epiplanktonic corpses; this is all the more potent an argument because

every one of the recorded occurrences in the epiplankton is nocturnal, that is between

7.0 p.m. and 4.0 a.m. The species therefore had apparently much the same distribution

as imbricata; that is, it was a mesoplanktonic form, coming to the epiplankton at night ;

its plurimum distribution when there was at 75-100 fathoms.

* Two specimens were also taken in 33 6, which has been omitted as non-comparable.

288 DR. G. H. FOWLER-——BISCAYAN PLANKTON :

It is noticeable that the specimens of Stage I. were from nets lowered to at least 350

fathoms: 34,/, 750-500; 23 .a(the doubtful female), 1000-750; and 36 /, 350-0 fathoms.

As the numerous captures which have hitherto been made from the Atlantic were

always of Stage IT., it seems likely that the oldest stage is only to be found in deep

water.

CoNCH@CIA IMBRICATA (Brady pars), Miller.

At 50 =) ( 7 per cent. of 13 hauls, with 0:07 ) average

75 | 30 > 10 op 2°20 t specimens

100 | 35 - 17 a" 1:52 J per hour haul.

Between 200-100 fathoms 0 ‘utan7 , 000

250-150 ¢ ‘thisapecies 4 9 1) Bat, (0:00 average

300-200 | occurred in 1 i; 3 1°00 |, specimens per

400-300 | Sucve 3,4, 166 | 100 fathom

500-4.00 2 2 3 ee 1:00 haul.

750-500 | ae a, 0403

This species was plentiful at no depth; it failed at 0 and 25 fathoms. The single

specimen captured at 50 fathoms was only 1 mm. long, but there did not seem to be any

general indication that any stage had a preference for any particular level.

It appears obvious from the table that imbricata was not present at all in the upper

epiplankton, but that it extended at least to 500 fathoms. In such a case as this, where

the species is uncommon in the epiplankton, it is fairly certain that the mesoplanktonic |

specimens were living at the lower levels and were not merely falling corpses.

It is further of interest to note that all the ten occasions on which it was captured in

the epiplankton were between 7.0 P.M. and 4.0 a.M.; this strongly suggests a rise from

deeper water at night ; these 10 hauls form 32 per cent. of the comparable night hauls,

and are therefore a fair test of the point.

The horizontal distribution in the epiplankton was quite local, even in the small

area studied : the stations were all in the southern part of the area.

Although this species failed in the hauls with closing-nets between 250 and 100

fathoms, it was captured in the serial hauls 36 g, h, & (200-0, 250-0, 300-0 fathoms)

in such numbers as to ensure that the specimens were not merely caught in the hauling

of the nets to the surface.

CoNCHGCIA INERMIS, Claus.

This species was observed only in a serial haul, 86/ (350-0 fathoms), and no

conclusion as to its horizon can be made.

ConcHa@crA KAMPTA, Miiller.

This was represented only by two males of the same stage, which were taken in two

hauls (226, 34e) between 750-500 fathoms. The species was presumably purely

mesoplanktonic.

THE OSTRACODA. 289

CoNCH@CIA LORICATA, Claus.

At 50 7 23 per cent. of 13 hauls, with 0°30 average

75 | 60 5S 10 3 0:60 \ specimens

100 | | 47 3 17 S6 1:58 J per hour haul.

Between 150-50 | fathoms | 1 out of 1 i 1:00 )

200-100 P this species 1 1 5 7 3 0:14 dverase

250-150 | occurred in 0 as 3 S9 0:00 : a

0-20 | profs 2 om ptomar

400-300 Hal 3 3 % 0:66

500-400 | ee a 2) oa hank:

750-500 J at ‘ te 3 » O10

It occurred also in three non-comparable hauls, one of which was at 100 fathoms.

Unlike some species already dealt with, loricata was found in the epiplankton by day

as well as by night. Of the 17 epiplanktonic occurrences, 8 were during daylight, and

contained 24 of the 37 specimens (numbers multiplied by time-factor). The epiplanktonic

specimens were comparatively so few that the mesoplanktonic specimens cannot be

dismissed as dead or dying. This species would therefore seem to have belonged to the

lower epiplankton and upper mesoplankton, with a maximum at 100 fathoms, and

apparently another at 500-400 fathoms. The mesoplanktonic specimens were on the

whole smaller than the epiplanktonic.

CoNCH@CIA MAGNA, Claus.

At 0 > ( 38 per cent. of 13 hauls, with 0°84 ee

25 | | 41 - i 6 1-88 Wee:

50 92 ‘ 134, ~— 22°38 em iey

75 | | 90 4. HOP ;, 17-00 i ala

100 | | 100 . iw. 3411 matt

Between 150-50 1 out of 1 3 6:00 >

200-100 | fathoms | 7 a 7 285

250-150 ¢ thisspecies 4 3 i: 3 ; 1-00 |

300-200 | occurred in | | a 3 if 0:33 | ghee

400-300 | | a oe 3» 066 | Eanes

500-400 2 ‘ Ts cae

750-500 | | t ; a. 110 | ae

1000-750 3 Ue 5 zs 0:40 j

1250-1000 | | 0 i ~~ 6-00 |

1500-1250 J irr 3 a. + o20/

From this general table it would seem that the species lived in considerable numbers

in the lower epiplankton (50-100 fathoms) and upper epiplankton (100-200 fathoms).

Below 200 fathoms the captures are so few in numbers that, considering the very

large numbers near the surface, we may with safety attribute them to dead or dying

290 DR. G. H. FOWLER—BISCAYAN PLANKTON:

specimens. The slight rise in “average specimens per 100 fathoms” at 750-500 fathoms

has been noticeable in other species, and will be discussed later (p. 297).

The following table gives the comparative prevalence by day and by night :—

At. 0 7 ( 62 per cent. of 8 hauls by day, with 1-37

| 0 2 5 rs night, ,, 0:00

25 | 50 es 6 se days 5, «16

| uiliie 33 5 6 7 night, +,, 2°50 average

50 | ‘ ; | 85 ; ay ays ef

5 L tis species” J ) x if ee cay, “ee te L specimens

| é i 100 S4 6 oe night, ,, 38°50 | per hour

se occurred in A

or | 100 : 3 ee day, ,, 16°33 haul.

| 85 a 7 > mght, ,, 7:28

100 100 ae 9 33 day, ,, 24:88 |

J L 100 ; (SE onicit, ,, 44500)

At 50 or more fathoms the chances of capturing the species (percentage of hauls)

were approximately equal by day and by night, and the greater number of specimens

was also below this depth both by day and night. The small but uniform excess of

specimens taken by night at 50, 75, and 100 fathoms over those taken at the same

depths by day seems to suggest a slight nocturnal movement upwards of specimens from

the upper mesoplankton.

The total numbers at the surface and 25 fathoms are so small that it does not seem

profitable to discuss the reaction to rain, &e.

With the large numbers of specimens available it seemed advisable to ascertain

whether a particular stage exhibited a preference for any particular horizon in the

epiplankton. The following table shows under I., IJ., and III. the percentage of the

total specimens of that stage which was found at each depth; unlike the other tables,

this gives (for obvious reasons) the actual numbers observed, not multiplied by a

time-factor :—

I. Il. III.

At O were captured 3°6 0:9 0-4.

25 BS 36 0-9 21

50 a 27-9 13'8 31-2

75 ps 58 12°8 16°7

100 58°8 71:3 49°3

Se) oo

This table gives an interesting but negative result, in that there seems to have been

no stratification according to stages; all three stages were most plentiful at 100 fathoms,

and more so at 50 than at 75 fathoms.

As with some other species which have been worked out on similar lines, the horizon

of 75 fathoms shows lower figures in the tables than are found at 50 and 100 fathoms.

The reason for this is still to seek; but the observation is interesting, as contradicting

the suggestion (which has more than once been made to me) that greater numbers

at lower depths in the epiplankton are due to specimens caught while hauling the open

THE OSTRACODA. 291

net to the surface from the horizon where it has been fishing; were this so, the results

at 75 fathoms should be intermediate between those at 50 and 100 fathoms; as a fact,

they are often not so. The same relation has been noticed in some species at a higher

level, 25 and 75 fathoms having a preponderance of specimens over 50 fathoms.

A possible explanation is suggested on p. 303.

Tort A Larva.

Though the exact attribution of the individual specimens may in some cases be

uncertain, there can be little doubt that the majority of these larvee can be safely assigned

to magna, apart from the morphological grounds dealt with in the Systematic Part.

Of the total specimens * of the five species likely to have been represented by larvee

of this general type, magna formed 87 per cent., zetesios 1, hyalophyllum 6, loricata 8,

spinirostris 1 per cent. Under the reasonable supposition that the relation of larvee

to adults is anything like proportional in the different species, it is probable that by far

the larger number belonged to magna. With the reservation that a small percentage

may have belonged to other species, the A larve are here attributed to magna for

statistical purposes.

At 0 es Ze per cent. of 13 hauls, with 0:76 > oe tee

50 fs! 4, ey.’ , . “16-46 + ae a0

75 | | 00 Pumas. 7 52:10 |p hi fe

100 | | 88 . 17 A 19°70 ) :

Between 150-50 j 1 out of i 33 500 >

200-100 | fathoms | 6 4 ee er |

250-150 ¢ this species 4 9 r Bee ah 166 |

300-200 | occurred in | 3 2 3 rs 1:33 | ate ke

400-300 1 a 3, 1:00 | specimens

500-400 | | 1 : een 35.) LOGS t ee A es

750-500 | | a. ee a6 |

1000-750 il x 5 Q 0-08 haul.

1250-1000 | | 0 i he 00

1500-1250 J Ca ~ Re

The distribution appears to be much the same as that of magna: that is to say, these

larvee were plentiful in the epiplankton and down to about 200 fathoms; below this

depth their scarcity, as compared with the large numbers at higher levels, probably

indicates that the few specimens captured were dead or dying.

But there is a slight difference from the corresponding table in magza, in that a

distinct plurimum is observed at 75 fathoms; further, the slight rise in population at

about 750-500 fathoms which is noticeable in several other species is not clear here,

though there is a marked drop in the captures below 750 fathoms.

* Actual numbers, comparable hauls, epiplankton.

SECOND SERIES.—ZOOLOGY, VOL. X. 47

292 DR. G. H. FOWLER—BISCAYAN PLANKTON:

The next table records the distribution of these larvee by day and by night in the

epiplankton :—

At 0O > ( 37 per cent. of 8 hauls by day, with 1°25

{ ! 00 _ 5 pe micht= s, 0:00 |

95 3 | 83 op 6 A day, :, 9:33

50 | fathoms | = » : ” ay 9 Be | average

+ these larvee | ion 2 £ » ee ” Rees ' specimens

occurred in 22 2 aD, per hour

a | | he 2 3 2 day, ,, 23°66 | haul.

85 » Ceweeuieit, ,, 65/71

100 | | 77 5 9 aN day, ,, 10°22 |

J Vado") ij) <eeeOReicht, ,, 30372

With them, as with magna, there is an increase in the night population at 25, 50, 75,

and 100 fathoms, which seems to point to a nocturnal rise of specimens from 200—

100 fathoms. The plurimum at 75 fathoms is more marked by night than by day.

CoNCH@CIA PROCERA, Miiller.

At 0 7 per cent. of 13 hauls, with 0°15

e 4 ( average

25 | | 0 . 12 = 0-00 :

specimens

50 | 0 sy 13 Ms 0:00 L

ve per hour

75 | 50 - 0 a On ‘i

aul.

100 70 i 17 as A-41 )

| fathoms

Between 150-504 5\ this anccios 4 1. VCHUCRNNNGINNNIG 4°00.)

200-100 | occurred in 6 ” 7 23 2-00 | average

250-150 1 a 3 “4 0:33

3800-200 | | 1 3 0:33 specimens per

x 2 2 100 fathom

400-300 | 0 . 3 it 0:00

| haul.

500-400 0 ie 3 os 0-00

750-500 J eer 4 ees | 010%)

The species was, comparatively speaking, rare; it was taken only once at the surface,

never at 25 or 50 fathoms. The table shows a plurimum for the epiplankton at

100 fathoms, and that the species extended in fair numbers into the 200-100 fathom

zone. The single specimens and fractional averages below this zone may be attributed

to dead or dying specimens. Analysis of the epiplankton captures showed no trace of a

nocturnal rise from the upper mesoplankton.

CoNCH@CIA PUSILLA, Miller, var. MAJor, Miiller.

This species was only captured

Between 750-500 fathoms in 3 out of 4 hauls, with 0°50 average specimens

1000-750 55 Li) ssstaato a3 0:08) per 100 fathom haul.

THE OSTRACODA. 293

CONCH@CIA RHYNCHENA, Miiller.

Between 3800-200 1 out of 3 hauls, with 0:33

400-300 fathoms Plldiacstid 1) 4 1:33 ie ato

500-400 this species 5. eo 3-00 Tae per

750-500 occurred in 9 5 4 a 1:20 | 1 athom

1000-750 1 es a 0:24 haul.

This forms a typical mesoplanktonic distribution, yielding a regular spindle.

CONCHGCIA ROTUNDATA, Miiller.

The following table shows the distribution (1) in the epiplankton, (2) of specimens at

Stage IT. or earlier in the mesoplankton, and (3) of specimens at Stage I. in the

mesoplankton :—

At 0 ) a per cent. of 13 hauls, with 0:1 )

| average

25 fathoms ke s 12 55 1:9 :

3 : specimens

50 > this species fe 13 FA 46 j

| ; per hour

75 occurred in _ ye 10 55 62°2

J | haul.

100 88 ps 17 - 14:3

Between 150-50 | ( 1 out of 1 5 6:0

200-100 | 4 8 7 . 4°8

250-150 | fathoms | 2 » 3 ” 0°6

300-200 l young 4 1 7 3 ” 0-6

400-300 specimens (0) 5 3 4, 0:0

500-400 | occurred in | 0 ” 3 » 0-0 a

750-500 2 He A " 0:3 specimens

1000-750 J Lo ees, OF per

100 fathom

400-300 > 2 » 3 » 1:0 haul.

500-400 a 2 ” 3 ” 16

ls 4 i a4

750-500 Segal: 4 is 4 ‘ 0-5

1000-750 3 4 5 ” On4

occurred in

1250-1000 | 0 4 3 i, 0-0

1500-1250 LA 4 2 Pe 0-4 J

The general distribution was that of ewrta. We have a species which had a plurimum

at about 75-100 fathoms, but extended to the surface. Down to about 200 fathoms the

smaller specimens, Stage II. or younger, were fairly plentiful. Their lower limit would

seem to be at about that level, and lL regard at any rate most of the few small specimens

caught at greater depths as dead or dying, or perhaps sinking for their last moult. On

the other hand, the larger specimens at Stage I. seem to attain a plurimum between

500 and 300 fathoms. It is not suggested that no large specimen ever rises into the

epiplankton, but that the oldest stage as a whole seeks deeper water.

47*

294, DR. G. H. FOWLER—BISCAYAN PLANKTON:

The specimens at 0, 25, and 50 fathoms were too few to give any indication of diurnal

oscillation or of reaction to rain. But

At 75 fathoms the average catch was 35:00 specimens by day,

73°85

2” ” ”

100 o>; »

” 3)

8°66

20°75

”

night,

day,

night,

showing a rise in the population at both horizons by night, and a plurimum at

75 fathoms for both day and night.

CONCH@CIA SPINIFERA, Claus.

At 50

fathoms

250-150

800-200

400-300

500-400

750-500

100 |

Between 200-100 |

1000-750 J

this species

occurred in

( 15 per cent. of 13 hauls, with 0°46 } average

2°30 \ specimens

2°00 J per hour haul.

0-14

1:00 average

0°66 specimens

1:66 \ per

0°33 | 100 fathom

0°40 haul.

0:08 J

All the epiplanktonie specimens were taken by night, which points to a nocturnal

The species was so scarce at all depths that it is

doubtful where its plurimum (if any) was to be found; perhaps somewhere between

rise from the upper mesoplankton.

400 and 150 fathoms.

CoNCHGOCIA SPINIROSTRIS, Claus.

= C. porrecta, Claus.

The total number of specimens is so small that to reduce them to the usual “ average

specimens per hour haul” would be rather a farce.

At 0)

25 | fathoms | 1

50 this species 1 5

(9) occurred in A

100 L 5

”

The table * shows the rarity at all depths.

epiplankton, it is not surprising that none were captured in the mesoplankton.

* Actual numbers; not multiplied by a time-factor.

”

( 1 out of 13 hauls, with O by day +1 by mght =1 specimen.

=1 ”

=7specimens.

=s hoe

=7 ”

As there were so few specimens in the

THE OSTRACODA. 295

ConcHa@cora TyYLoDA, Miiller.

One unmistakeable specimen occurred in 24a (1250-1000 fathoms); and a pair of

empty shells which seemed also attributable to this species was found in 302 (1500-

1250 fathoms).

CONCHG@CIA ZETESIOS, sp. n.

The specimens were so few that they are better not expressed in the usual averages.

A plurimum (if the word can be used of so small a number) was, however, noticeable at

100 fathoms. The species would seem to have inhabited the lower epiplankton and

upper mesoplankton. Only three specimens were taken by night.

At 50 ) ( 2 out of 13 hauls, with 4 specimens *.

75 fathoms 2 5 10 ” 2 ”

100 this species 3 iy ee ” ll ”

Betmecraciosoo my cued in | ee dt,

300-200 Ike 3 » 1 »

HALocyPrRis GLOoBosaA, Claus.

The following table shows the distribution of this species in the epiplankton; it has

clearly a centre in the lower epiplankton, the specimens were thickest at 50 fathoms,

the occurrences most numerous at 50, 75, and 100 fathoms :—

At 0O 15 per cent. of 13 hauls, with 0:5

25 | fathoms 58 3 12 FS 2:2 average

50 this species 84 a 13 o 149 specimens

75 occurred in 80 a 10 3 9°7 | per hour haul.

100 J 88 n 17 . 3°6

Below 100 fathoms only one specimen was captured, the single male at 750-

500 fathoms.

This is remarkable because the species was common in the epiplankton, and many

specimens must die, yet not a single one appeared in the closing-nets. This fact

suggests that a comparatively large form (84 per cent. of the specimens were over

2 mm. in length), when dead and sinking, is more likely to be snapped up for food

in the dark, than a tiny form such as curta or rotundata; this seems reasonable,

because there is more of it to be touched or smelt.

* Actual numbers; not multiplied by a time-factor,

296 DR. G. H. FOWLER—BISCAYAN PLANKTON:

At O ( 25 per cent. of 8 hauls by day, with 0:8 |

| 00 . B=) mehte 4.) 0:0

| ; 66 x 6 % dave. cin

| fathoms | po 29 6 ,, night, , 29 | average

7 this species + Se ” Os apt day, > 10:0 | — specimens

occurred in | Bk 2 6 ” night, ,, 206 | per hour

75 100 a 3} A day, » 28:3 ait

| | 85 2 7 »” night, ” 1e7/

100 | 88 5 eattehede , 51

J eae ” 8 op mietit: ., 20.)

It would seem possible that the plurimum at 75 fathoms by day rose to 50 fathoms at

night.

ARCHICONCH@CIA CUCULLATA, Brady.

This species occurred in the following hauls:—32/ (400-300 fathoms), 34e (750-

500 fathoms), 27 (1250-1000 fathoms), 27a (1250-0 fathoms). It was obviously a

member of the deeper mesoplankton.

CYPRIDINID&.

CYPRIDINA CASTANEA, Brady.

This species occurred in the following hauls :—32m (75 fathoms), 32 p (100 fathoms),

36g (200-0 fathoms), and 86% (250-0 fathoms). It is worth noting that the two

epiplanktonic captures were between 10.30 p.m. and 1.30 a.m.

GIGANTOCYPRIS PELLUCIDA, Miller.

The two captures of this species give the first definitive evidence that it is a

deep-water form, previous captures having been made with open vertical nets. Both

are very deep: 31d at 1000-750 fathoms, and 26 6 at 2000-1500 fathoms.

THE VERTICAL DISTRIBUTION OF THE OSTRACODA AS A WHOLE.

The first point to be considered is the general distribution of the planktonic Ostracoda

(practically that of the Halocypride) during the period and through the area in-

vestigated. This can best be grasped by taking the comparable hauls at each depth,

and the average specimens per hour or per 100 fathoms which they yielded. To the

specimens recorded in the General List (pp. 312-313) have been added all specimens

which were too much broken for identification, a few indeterminable larvee, and the

seven species which occurred so rarely as not to have been printed in the general list.

THE OSTRACODA. 297

Hauls 27a and 36/ are of course omitted. The table following gives these general

results; they are diagrammatically expressed in figure K, p. 298.

At (0) fathoms in 13 hauls were 8:15

25 ie > ee are

50 .) Ise 92°23 ¢ eae

is ‘ aA : hanes : per hour

100 4 17 re 100758 J oe

Between 150-50 A 1 : 30°00 *)

150-100 ® 1 z 28:00 |

200-100 . 7? aah 21°85

250-150 3 3 ” 10-00 | average

300-200 ” 3 ? 11°38 | ie oiacis

400-300 iH 3 aes 13:33 |

500-400 i" 3 20°33 f ee

750-500 5 4: SME YS:90 | haul.

1000-750 Bie aan 3°76 |

1250-1000 , 3 is 0°80

1500-1250 : 2 ‘s 1:40 |

2000-1500, 2: Se 0-10 )

The table shows in the first place how admirably adapted are Ostracods for the study

of oceanic planktology, by their great numbers at even considerable depths. The next

thing obvious is the plurimum at 75 fathoms, as compared with the other epiplanktonic

horizons studied ; from this the distribution tapers upwards to the surface, downwards to

about 250 fathoms.

Less obvious, but apparently representing a real fact, is the broadening out of the

distribution spindle (fig. K) between 750 and 3800 fathoms, to which reference has

been made in the discussion of the distribution of several species; the same thing

has been noticed in some earlier parts of this series of papers. This puzzling

phenomenon may perhaps ultimately find its explanation from Ostwald’s recent work.

He has shown that the viscosity (innere Reibung) of sea-water increases very rapidly

with diminishing temperature or increasing specific gravity; and he and Brandt have

both shown how very slight a difference in specific gravity determines whether an

organism shall sink or float. It seems possible that for each species, according to its

own specific gravity and contour-resistance (Form-Widerstand *), there will come a

point in its fall towards the bottom, when dead or dying, where the increased specific

gravity of the water (due to pressure) and the much diminished temperature produce

a viscosity which so nearly balances the excess-weight of the animal over that of water

(Uebergewicht) as to reduce the velocity of descent; these points, or rather levels, will

be different for different species, and will together form a zone where dead and dying

animals are more abundant than they are above that zone.

* For the explanation of the terms and for the whole question see Ostwald: ‘ Theoretische Planktonstudien,”

Zoologische Jahrbiicher, Abtheil. Systematik, Band xviii. 8, 1-62.

298 DR. G. H. FOWLER—BISCAYAN PLANKTON:

In that zone there would be a happy hunting-ground, a region of maximum food-

supply, for the purely mesoplanktonic species. Taking the species, and the oldest

stages of species, which were recognised above as having been purely mesoplanktonic

during the Biscayan cruise *, we find that

the plurimum of ametra was at 500-400 fathoms.

3 brachyaskos Fe OOO nis,

as curta, Stage I. », 750-500 -

a pusilla oO -000) i,

5 rhynchena » 000-400 D

oi rotundata, Stage Il. ,, 500-400 ,,

This fits in well with the foregoing suggestion. These mesoplanktonic species, though

few in actual numbers, of course help to swell the total averages in the table (p. 297)

and diagram (fig. K); but if they are taken out, the result is only to put the

point of greatest mesoplanktonic intensity of epiplanktonic species a little higher (about

400 fathoms). The whole question seems worthy of attention for future expeditions.

Fig. K.

tt)

_ es

100

200-100

250-150

300-200

400-300

500-400

700-500

1000-750

1250-1000

1500 1250

2000-1500

Distribution in averages of all Ostracods at all depths (comparable hauls).

EXPLANATION OF PLATE 27.

The upper part of this Plate represents diagrammatically the observed distribution of

the different species captured.

* Omitting scarce forms as too few to be significant.

THE OSTRACODA. 299

In such a study as the present, where it is difficult to assimilate the meaning of rows of figures of

population at various depths, it seems easier to grasp the distribution visually by representing it as a

symmetrical plane spindle, rather than by the ordinary curve. This is done by erecting the base-line,

by laying off each observation on both sides of the line, and by joining the points thus obtained ; in

other words, two ordinary curves are set back to back in order to make a symmetrical figure. By this

method (which is by no means novel), the maximum intensity—for which I suggest the term plurimum—

becomes readily conspicuous.

The observations plotted on the upper part of Plate 27 are :—(1) Average specimens per hour haul

for 0, 25, 50, 75, and 100 fm. ; the ordinates are set opposite to the depths at which the open nets were

towed horizontally. (2) Average specimens per hour haul for greater depths : the ordinates are in this

case opposite to the middle of the water-column through which the closing-nets were hauled vertically ;

thus the average for 400-300 fm. is plotted at 350 fm., the average for 750-500 fm. at 625 fm. This

seemed to be the fairest way of representing the facts *. Fractional averages less than 0°5 are represented

by a thin line ; if more than 0°5 they are taken as 1:0. The hauls with the closing mesoplankton net

are separated from those with the open horizontal epiplankton nets by a white space or line. All the

figures are plotted to the same scales. The averages per hour haul and per 100 fathom haul are of course

not directly comparable with one another, because the mass of water filtered by the vertical closing-net

is so much the smaller.

In the lower part of Pl. 27 similar diagrams, to the same horizontal scale, have been used to express

roughly my interpretation of the observed facts, and have therefore only the value of a personal opinion.

These “ distribution spindles” are obtained (1) by omitting those captures which I regard as representing

only dead or dying specimens on the grounds already given (pp. 282-3); (2) by a process of

“smoothing the curves” by drawing lines from the plurimum to the inferred upper or lower limit,

paying regard to intermediate averages in the epiplankton. In these diagrams, unlike the others, it

seemed fairest to extend the “ distribution spindle ” to the extreme possible points, in order to allow for

scattered specimens which the net might have possibly missed, owing to the thinning out of a species as

we recede from its plurimum in both directions vertically. Thus, if the highest admitted specimens were

in a 300-200 fm. haul, the figure has been carried up to 200 fm.; if the lowest admitted specimens

occurred between 750-500 fm., it has been carried down to 750 fm.

The same general methods have been adopted for the graphic representation of day and night distribution

in fig. L (p. 302), but on a doubled vertical scale.

These diagrams show conclusively how valueless are any generalisations as to the

vertical distribution of even a genus of Ostracoda from one place, day, or even hour to

another. Still less can such generalisations be made for a family or group. Each

species seems to be in a state of chronic movement, and must be studied separately, as

an entity with its own specific likes and dislikes; this should be attempted at every

separate geographical position possible, if we are ever to understand the laws of

planktology.

* The averages for the closing-net 150-50 fm. (21 p) are therefore on the 100 fm. ordinates, as well as those

for the horizontal open nets at 100 fm. Fortunately, the averages only coincide in the case of procera, and will

therefore not lead to confusion.

SECOND SERIES.— ZOOLOGY, VOL. X. 48

300 DR. G. H. FOWLER—BISCAYAN PLANKTON :

THE VERTICAL DISTRIBUTION OF INDIVIDUAL SPECIES.

* In"summary of the observations given above, it may be said that the species seem to

haveibeen distributed—at the date and in the area investigated—on the following lines:

(a) Species confined to the epiplankton . . . haddoni, spinirostris, globosa.

(b)£Species with a plurimum in the epiplankton,

but extending into the upper mesoplankton.

ies distri ith thei 7

} magna and A larvee, procera, elegans, zetesios.

oldest stage purely mesoplanktonic .

(d) Species extending into the lower epiplankton

a bable) plurimum intheupper|. , . ; mr k

a ee) : ane - Ade Wes. loricata, spinifera, daphnoides.

mesoplankton, extending into the lower |

mesoplankton.

(e) Purely mesoplanktonic species . . - « ametra, brachyaskos, pusilla, rhynchena.

To (e) may probably be added eines, tyloda, cucullata, pellucida ; to (b) castanea.

Those species which occurred at any time in the epiplankton may be also classified as:

mMigeeehich seachedun 40° Om { curta, haddoni, hyalophyllum, magna, A larve, rotundata,

{ spinirostris, globosa.

ene ” » 29 5, daphnoides, elegans.

0 7 a » 950 ,, imbricata, loricata, spinifera, zetesios.

” » ” ” 75 ” procera.

It remains to be seen whether, as is possible, this relation is connected with

temperature barriers.

It is interesting to note that of Miiller’s new ‘ Valdivia’ species which were captured

by the ‘ Research,’ ametra, brachyaskos, pusilla, kampta, rhynchena, and tyloda were purely

mesoplanktonic species ; and that “ stigmatica”’ and “ lophura” were apparently meso-

planktonic oldest stages of known epiplanktonic species. ‘“ Macrocheira” and

“ ctenophora” seemed to be similarly oldest stages of epiplanktonic species, but were

apparently themselves epiplanktonic. It is quite evident that the mesoplankton will be

far more productive of new forms than the epiplankton.

Definitive Observations.

T have employed this term elsewhere to denote those observations which show the

outside limits of depth, temperature, &c. between which a species has been captured ;

they are brought together in the first two main columns of the ensuing table under the

heads of “ lowest possible” and “ highest possible” depths and temperatures. To these

I have added—as the expression of a mere personal opinion—my own inferences as to

the real lower limits, under the heads of “lowest probable” depths and temperatures.

The third and fourth main columns recapitulate, for convenience of reference, the

oliserved plurima, and those general inferences as to distribution and oscillation, in the

area and during the period of the cruise, which have been drawn in the text. The

temperatures from 25-75 fathoms are unfortunately only approximations (see p. 5);

the others from the curve of observations made during the cruise.

301

THE OSTRACODA,

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302 DR. G. H. FOWLER—BISCAYAN PLANKTON:

THE VERTICAL DIURNAL OSCILLATION OF THE EPIPLANKTON.

It is obvious from the account of the separate species already given that many of

them were taken in greater numbers by night than by day. It has been urged upon me

more than once in connection with other groups that this is an argument, not for the

presence of organisms in greater numbers at night, but for their seeing and avoiding

the nets by daylight. Such a criticism can hardly apply to the Halocypridze, which

have no eyes.

Fig. L.

4-0A.M. To 7:0 P.M 7-O p.m TOo4-0A.M

100

, CURTA CURTA

100

5 MAGNA MAGNA

100

: A LARVAE A LARVAE

100

: ROTUNDATA ROTUNDATA

100

GLOBOSA GLOBOSA

Spindles of day and night distribution of five Halocypride.

To what, then, is their capture in greater numbers by night due? I can see no other

explanation than that the population is actually increased by a rise of additional

specimens from lower levels.

If tow-net hauls could be taken simultaneously at every zone every half-hour for the twenty-four

hours, it should be possible to trace the gradual increase and decrease in numbers, and it is with the

idea of suggesting such an experiment for the next deep-sea expedition that I venture to print this

paragraph. But the work will demand a large and wakeful staff of naturalists.

THE OSTRACODA. 303

Supposing that some oceanic species do actually oscillate vertically in the manner attributed to

Limnoplankton and Neritic Plankton, there seem to be two possible methods. (1) In the one case, a

species may oscillate (as it were) in one piece, plurimum and extremes alike falling and rising simul-

taneously ; in this case the distribution spindle will retain its shape and proportions but will alter its

position in depth. As an illustration of what would seem likely to happen in this case, the

accompanying diagram (fig. M) of the actual distribution of curta during the cruise has been drawn.

On the ordinates of the twenty-four hours, the numbers of specimens captured x time-factor have been

plotted on both sides of abscissx representing 25, 50, 75, and 100 fathoms*. The spindles obtained by

joining up the ordinates seem to show a plurimum at 25 fathoms at 8.0 p.m., at 50 fathoms at 11 p.m.

and again at 1.0 p.m., and at 75 fathoms about midnight. These can be interpreted to mean that the

plurimum at 75 fathoms at midnight rises to 50 fathoms by 1 P.m., and to 25 fathoms by 8 P.m., that it

sinks again to 50 fathoms by 11 P.m., and back to 75 fathoms at midnight, the fall, aided by gravity,

being naturally more rapid than the rise. The slight increase at 100 fathoms towards midnight may be

Fig. M.

25 FM 50 FM. 75 FM. I0O FM.

PM Of : —— A

due to reinforcement either from above or below, but the numbers were fairly steady at this level all

through the twenty-four hours. When similarly treated, there are indications of the same sort of thing

in magna, rotundata, and the A larv, but they are not so clear. The occurrences of the other species

were too scattered, and their numbers too few to give any clear result. This oscillation, if true, would

account for the puzzling two plurima at different levels, noticeable in the distribution spindles, not only

of Ostracods but also of some other species already treated in this series of papers. Thus, for example,

the double plurimum of magna (fig. L) is apparently produced by a plurimum at 50 fathoms about

9.0 v.m., and another at 100 fathoms about 3.0 a.m.

(2) If only a certain percentage of the specimens of a species rise and fall, the gain and loss will

balance at each horizon except the highest and lowest; the plurimum will remain steady, and the spindle

will alter its shape and proportions. None of the diagrams made from the ‘ Research’ specimens seem

to suggest this.

* The specimens at 0 fm. were too few to be significant.

304 DR. G. H. FOWLER—BISCAYAN PLANKTON:

As to the agency, be it mechanical, chemical, or physical, or a combination of these,

which appears to bring certain species up at night, I have only to remark that the

distances which have to be traversed in the time seem too great for Ostwald’s explan-

ation to be alone adopted for all oceanic species; besides, it is not the whole oceanic

plankton that oscillates (as it should by his theory, except in the case of powerful

swimmers) but only certain species, if my deductions are correct. Nothing is more

puzzling than the sudden appearance during the dark hours (often in very large numbers)

of a species which was seldom or never taken in the epiplankton in daylight during the

whole cruise. For example, with the exception of a single specimen at 100 fathoms at

mid-day, all the 204 epiplanktonic specimens * of daphnoides were captured between

8.0 P.M and 3.30 A.M., on fifteen occasions extending over six nights and over an area of

(roughly) 45 x 15 minutes. Similarly all the 55 * epiplanktonic specimens of imbricata

were captured between 8.0 P.M. and 3.30 A.M., on ten occasions extending over four nights

in an area of about 35X15 minutes. In such cases the question is not one of a confined

swarm, but of similar, if scattered, observations over a fairly large area and period.

The following species showed increased numbers in the epiplankton by night :—curta tT,

daphnoides, elegans, hyalophylluin, imbricata, magna t, A larvee +, rotundata +, spinifera ;

of these nine, three were never captured at or above 100 fathoms by day, one only once,

one only twice. ‘The following showed no such variation in number by day and night :—

haddoni, loricata, procera, spinirostris, zetesios, globosat, but in the last case the

plurimum seemed to rise at night.

A point which requires consideration is, how far the plurima observed during the

cruise may have been due to some specially favourable conditions on a particular night.

On investigation this appears to have been partially the case ; this will be seen from the

following list, in which are given, for the more plentiful species, those hauls at which

the greatest average number per hour were captured :—

259/80f 30g 301 31 6 |32m| 32 n/ 32 0\32 p 33¢ 339 34d) 35a) 35a) 35y |

Cg Rete te Lao pe Pte fic fae) os | GBH MC GHT 155/126.) ... |.

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Clegans; co) Boe: Oe non ensue bce (23) oe

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SPUNUPERD shore eteheteieye oy Ee ee nom eee ual toe ||, co || kas) ais

It is obvious that the night on which hauls 32 m, n, 0, p were made was exception-

ally rich: my log records “ very fine, smooth, pitch-dark”; but it is doubtful whether

the weather had any bearing on the point, as all these four hauls were made at 75 and

100 fathoms. This night, however, was not uniformly the best for all species: magna

was far more plentiful in 25 gand 34d; daphnoides again was most plentiful on yet

another night.

* Actual numbers. + Compare figure L.

THE OSTRACODA. 305

SIMULTANEOUS AND CONSECUTIVE HAULS.

It was not realised when the Biscayan cruise was planned how complicated are the

movements of the epiplankton. My aim was, to get at least one haul at every hour of

the twenty-four at every depth (0, 25, 50, 75, 100 fm.), and more than one at the depths

and hours which were believed to be “ critical”’ : this plan was almost completely carried

out; and in a case where mesoplankton hauls have also to be attended to, where time is

limited and workers are few, it is about as much as can be done to fit the epiplankton

hauls into the intervals of the mesoplankton work *. But it has become apparent in the

course of these investigations that simultaneous hauls at the different horizons would

probably in many cases have been more instructive. Of these there were taken com-

paratively few, but they are significant as showing the “stratification” of species at

different depths and hours. A few examples of such hauls are given in the table

(p. 806), which illustrate various points. .

In the hauls, 30 m, 30 7, 31 a, 31 6 are examples of simultaneous hauls at 25 and 50

fathoms, taken in two consecutive hours. Both hauls at 50 fm. show nearly the same

species, the hauls at 25 fm. show little or nothing else than curta. This is a good

example of that stratification which ought to be (but is not) universally recognised

as a natural corollary of the admitted stratification of physical conditions. What-

ever may have been the decisive conditions at 25 fm., it is quite obvious that

curta liked them and that other species did not.

In the next series, 32 m,n, 0, p, taken at a time of night and at the horizons where

the fauna is thickest, a similar stratification is shown, not in the species, but in the

number of specimens of those species at the two levels.

In the third case, 35 y, 35 x, 36 a, 36 0d, the paired hauls were in the same night, but

not in consecutive hours: the interest of these lies in the fact that the first pair were

taken between 7.0 and 8.0 p.m. at the beginning of the dark hours and show few or

no specimens of those species for which on other grounds a nocturnal rise into the

epiplankton has been inferred (daphnoides, elegans, hyalophyllum, imbricata, spinifera) ;

the second pair, on the other hand, were taken in full night (11.30 P.M. to 12.30 a.m.)

and include all these species.

The fourth example, 25 e, g, shows the difference between two hauls at the same depth

at an interval of 24 hours; the later haul apparently struck a “swarm” of magna and

A larve, which had vanished again from that horizon before 2.0-3.0 a.m. of the same

night (25 h).

Haul 27. and Open Vertical Nets.

This non-comparable haul from 1250-0 fathoms (a length due to the mesoplankton net

having opened but not closed) has been worked out in detail, and illustrates the

impossibility of learning anything of the real distribution of plankton by means of

* In a swell, the manceuvring of the ship, in order to keep the wire rope of the mesoplankton net vertical, often

made it impracticable to work epiplankton nets simultaneously.

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THE OSTRACODA. 307

Vertical Open Nets, such as have been in fashion on recent expeditions. For the

serious study of plankton such hauls are a mere waste of time and energy, however

much they may fill museums and multiply species.

From this haul, by itself, nothing could be deduced except that the species included

were all present somewhere between 1250 fathoms and the surface, on a particular date,

at a particular geographical position. Contemporary observations showed further that

the range of possible temperatures was about 3° to 17°5 C., temperatures which

correspond roughly to the mean surface temperatures of Gibraltar and Archangelsk !

These vertical hauls do not even give a means of estimating the proportions in which

the various species are present in the area. This is shown by a comparison of the per-

centage which each species constituted of haul 27. (second column of the table below)

with the percentage which these same species formed of the total (actual) numbers

captured during the cruise (third column). ‘The fourth column gives the real distribution

of the species at the date and time of the cruise as deduced above from a comparison of

all the comparable hauls made; it shows—if, indeed, it be necessary to show it—what

a mixture of different faunas is brought to the surface by such a method of capture.

| |

eT ercanhase | As percentage of |

f ae 97 i | all specimens from | Distribution.

vinee | comparable hauls. |

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I UASIES 5 AOC O Ie 1-44 85

les and upper

NSE LESLOB tata vavo.c) cs's ais 'a) ss, 6.5.5 1-44 0:2 |

mesoplankton.

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EMPTORERISPCO:: «s/s 5,4) s/3i0s «3 7:24

Missing altogether were, not only the scarce forms brachyaskos, pusilla, and spinirostris,

but also the fairly common forms imbricala, spinifera, and globosa.

Except as regards the common species curta, rotundata, and magna, the percentages

SECOND SERIES.—ZOOLOGY, VOL. X. 49

308 Dk. G. H. FOWLER—BISCAYAN PLANKTON:

in haul 27 a would lead to most misleading inferences about the abundance or scarcity

of the several species in the district. The mesoplanktonic species in particular are in

excess of their real proportions because the net passes through so many more fathoms of

mesoplankton than of epiplankton.

It will be noticed that no attempt has been made to compare the foregoing results

with the conclusions of other observers. The reason for this is two-fold. It seems a

little dangerous to discuss the earlier faunistic records, because it is in many cases doubt-

ful whether two species which Professor Miller has now satisfactorily separated may

not have, hitherto, been reported as one. It ought, however, to have been possible to

compare the conclusions obtained by a study of the Biscayan material (for the area and

period of the cruise) with the records obtained by the ‘ Valdivia’ herself. Unfortunately

this is only the case to a very limited extent, owing to the fact tnat closing-nets were

used so little by that expedition, as compared with open vertical nets which in many cases

were sunk to considerable depths. Such nets, lowered to (say) 500 fathoms, bring up

a mixed sample of two or three different faunas from as many “climates” ; they record

only the latitude and longitude (which mean nothing to an animal) and a limit of depth

(more rarely of temperature), from below which the specimens captured cannot have come.

The hauls with the closing-nets would have been more significant if the upper 100

fathoms had been studied systematically at the same time, which was not the case. For

the present, therefore, it is better not to make any comparison between the records of the

‘Valdivia’ and the ‘ Research.’

V. MISCELLANEOUS NOTES.

Proportion of Males to Females.

If the numbers of the two sexes be expressed as percentages of the total specimens

measured, they come out as shown in the table on p, 309.

Leaving out of consideration for a moment the last two species, it would seem that

the females formed 56-64 per cent., males 44-36 per cent., of the specimens of the

majority of species: the four exceptions to this—ametra, haddoni, loricata, and

rhynchena—were represented by so few specimens that we cannot be sure that they are

really exceptions.

But the last two species are on a different footing. I have already hazarded the

suggestion that zetesios may possibly prove to be a parthenogenetic form of magna, but

as only 20 specimens in all were observed, males may have been missed if present only

in small numbers. The ratio between males and females of the fairly abundant globosa,

on the other hand, is startling, and recalls the old history of Apus. The ‘ Valdivia,’

like the ‘ Research,’ captured only one male, though the female occurred in 16 hauls and

presumably therefore in some numbers. Miiller (Naples Monograph, p. 175) regards it

as possible that parthenogenesis occurs in some marine Ostracods, but it has not been

proved for any Halocyprid ; indeed it is difficult to see how it can be “ proved” in an

oceanic species. Supposing the male captured in haul 22 0 to be of globosa, and not of

some other Halocypris (at least it seems to be of the same species as Miiller’s Valdivian

THE OSTRACODA. 309

Species. Specimens. Female. Male.

CUENATROD” GASES OR RAR ate Be 25 68 32

WNEIAID Soames os eo need 16 62 37

ULCER aren te ogy Sots slihcpsy se aeee 8 200 62 38

THE RMOULER MAY ta ares ehhh 200 56 44

LATEX BOSON eo o ies sania 565 57 42

rps tart tha iss my | 42 88 u

hyalophyllum —.. 2... 0 ee | 105 60 40

Ne a Oe | 101 64 35

aE | 62 79 20

LG TUE tt Seve Be etekege pecs : | 1171 64 30

POROGENG Ustenin nees xe a 147 57 42

MUMERCNT 3 cise 53 sid oe ete 39 71 28

OCUNQUEE Sars ae wi5c tine § a 378 61 38

GATT EN Oates n sere. crsfai lols sie 91 64 35

SMURUOSUNIS!: sve shat sye\ ss 08 23 56 43

ELE SUOB RADE 12 ayes < s5)/5 AA ai Syne 20 100 00

GPRLTOTD rea te Pheer 316 99 0-1

male), the fact that it was taken at great depths, while no female was captured below

100 fathoms, points to something very unusual about the domestic arrangements of this

species.

The Death-rate.

I had hoped to be able to work this out in several species from the actual numbers

captured at successive stages. But there was only one species which fulfilled the

necessary conditions for such a study—that it was large, plentiful, and with all its stages

represented habitually in the epiplankton*. This species was naturally magna, and it

is remarkable how its numbers are related. ‘The following are the actual numbers

measured and sexed: Stage I., 159; Stage II., 337; Stage III., 675. Now 675 -+2=337,

and 337 -2=168. That is to say, the total at each stage when halved yielded approxi-

mately the total for the next highest stage; or, in other words, the death-rate was

50 per cent. at Stages II. and IIT.

The ratio may be a mere coincidence: it takes for granted that reproduction had been

going on at a uniform rate for some time—a condition which was obviously not the case

in some other species. But the observation seems worth putting on record.

* The latter necessary, owing to the impossibility of direct comparison between the closing-nets and the others.

49*

310 DR. G. H. FOWLER—BISCAYAN PLANKTON :

The Occurrence of closely allied Species in the same Water.

It has been contended that, if the Darwinian canon of the Struggle for Existence be

well founded, closely allied species cannot co-exist in the same area; the one is bound

to succumb to the other. The point is worth consideration in such a collection as the

present; but the difficulty is to say what constitutes “close” alliance. In one sense,

all species of the same genus are closely allied to one another, even though they may be

as different morphologically as curta and daphnoides, and though their mere contour is

enough to show that they have responded differently to the stimulus of the Struggle.

Such forms are presumably in no more direct competition with each other than with

other members of the plankton.

Or, again, we may take as a standard those more subtle differences between the

species which Claus expressed as subgenera and Miller as “ groups”; these no doubt

bring together species of the closest morphological similarity, but take no account of

size. Thus, for example, by Miiller’s grouping, spznérostris * with a male mean length

of 1:3 mm. is in the same group as magna with a male mean length of 2°91 mm. It is

not obvious that these two would come into direct competition, but the smaller species

will presumably compete with the younger stages of the larger. Such groupings by

morphological similarity seem, however, to be the best that we can take as a standard of

“close ”’ alliance.

The species captured by the ‘ Research’ are tabulated according to their respective

groups on pp. 228-9; and in discussing this question I must take it as granted that

my deductions + about their vertical distribution—summarised in the lower half of

Pl. 27—are approximately correct.

As to the first pair of species—spinifera and inermis—nothing can be said, since the

latter was only observed in a haul which gave no clue to its distribution. The next pair,

however,—procera and brachyaskos—are interesting, since morphologically and in size

they are very close to one another; procera seems to reach down to about 250 fm. with

a plurimum at 100 fm., brachyaskos to reach up to about 300 fm. with a plurimum about

450 fm.; they apparently did not coexist in the same waters. Then come rotwundata and

pusilla, morphologically more easily distinguishable than the last pair, but of like size:

the younger stages of rotwndata were probably confined to the upper 200 fathoms, but

the oldest stage apparently overlapped pusilla to some extent; on the other hand, the

plurimum of the former was between 500-400 fm., that of the latter between 750-

500 fm.

Next is the magna-group, represented by at least three species, spinirostris being in

many points distinct and probably out of place here. Of these three, magna and zetesios

are of close morphological similarity and both of large size; they certainly seemed to

inhabit the same water, and to belong to the epiplankton and upper mesoplankton. On

the other hand, hyalophyllum, though rising into the epiplankton at night, seemed to

* Miller only places this species provisionally in the magna-group ; it seems to me to have more (though

uncertain) affinity with the loricata-group.

+ They were made and Pl, 27 drawn before this paragraph was thought of.

THE OSTRACODA. dll

be far more a mesoplanktonic form, and not to come into such direct competition with

magna, especially as its oldest or “ lophura ’ stage was probably purely mesoplanktonic.

Of the three species of the mo/lis-group, two were so scarce that no inference can be

drawn. The imbricata-group was represented by Stage II. of imbricata and ametra:

these apparently overlapped in the mesoplankton, but the plurimum of ametra seemed to

be about 500-400 fm., and 300 fm. to be its upper limit, while imbricata rose into the

epiplankton at night, and its real centre was probably somewhere in the upper

300 fathoms; although overlapping, these two seemed to have different centres of

distribution.

In summary—the only closely allied species which seemed to come into direct

competition were magna and zetesios.

VI. GENERAL LIST OF SPECIES AND SPECIMENS BY

HAULS AND DEPTHS.

With the exception of the first two (27 a, 36 /) the list has been confined to comparable

hauls. The number of specimens between 0 and 100 fathoms has been multiplied by a

time-factor, where necessary, to bring all to the standard one-hour haul; the numbers

below 100 fathoms are actual numbers. The columns headed “ Totals” include broken

specimens, indeterminable larvee, and eight species which occurred but seldom; the

captures of these eight will be found recorded in the text.

312

DR. G. H. FOWLER-—BISCAYAN PLANKTON:

(

Depth in

fathoms.

25—0

50—0

5—0

Haul.

- n

Gh NSS

S| 2

3 | 8

S$ =

= =)

curta.

daphnoides.

18}

oom GO: :

elegans.

haddoni.

dl Ole

FOES Ooh rite ct os seve

hyalophyllum.

Els

a2 3

| 8

eines

105

“cel

Sh |

Balad

12] 1

Baye

slic

Biles

| = | “A” larvee.

[S; on)

a Rone

- ep noc’

oR eH

procera.

Be hoe =a

> WEI. |

pusilla.

rhynchena.

é 3

Sie|s

Sessile

S| 8| 5/5

Siler. 1

4; 4 a

16 2 nee

3) aie

“oe

yee ee |)

| ae

S| 2), | Ca eee

23 alee

he dee | 2a a

1):

bl: eee

Sm).

hel ee

92... | aaa

PEW an (ih 1

275 6| 2] ..

63 ste

A tee

ae ae hea!

68| ..

35| $

globosa.

Totals.

2) aes

5} 56

2) 26

: 8

: 1

2| 4

2} 3

eal aded

Bia |)

Be a

Le,

6 | 247

7 | 156

2; 18

ae 2

7| 26

.. | 33

PA 24

aie 6

60 | 296

9) 22

6| 20

27| 88

17 | 329

33/181

23| 44

2/110

10; 14

5| 388

ooo

38 | 203

3) 59

1) 890

2 | 487

1| 70

Gis

1/318

44 |155

1| 215

.. | 215

THE OSTRACODA. 313

a : S . | :

Depth i - S ‘s = S : : : | g | S i

Ss ey S| Sls | Se lesa) s | 8) S12) S/S eis is

Sees eso] Se Sasa] Sal SSS Se RS | OR | Seas aes

| |

100—0 TVA an ene ee alice | cd ll acy | ROMs Was. | acc] 6 | cx Bodegas Tage

22 a * ste Nac c(h ce, (RIO EEN: O22 |. 2 | - 2| 18

246 he ee se! | hace ull-cee | ee Ener 7) 9 | ) Saban

24 e ine eet ie Mee |) jo). al ae al A e 6| 44

25 d Hales “ix: | ceva s| hae BUEN y 12) 1! 7 ae

30g lee Fel ca locas SOMMEGR EMTS! | cs 8 | Soleo einen

32d Bib ele |e | cr MAGI GM | G2], 28 | 9}..| 9/169

32 n Pip Ws deel 1 | OB. le edesiaoaN gt |. i fee dal ee (ton WiecS

32 p a0 7 (ad 4 | 187 | Si aenagal 6) .. 48 | 15 "| 1 [988

33d Tea es a a a Pa a ec | har i Giles. 1 i eoheas

345 Bile et 1 | 8) 100 a eraeeeale | 98| 7 .. | 6 {156

34d TO aes |. |. |e eee | 3+ 2/1 3/141

355 Gea NBs. Bo) 1. |. ee esos) 4. | .. | 15 | 2 | 123

35 BTW exo | as |: aw, | ocala Oa On tes. 13 2| 42

35 x 5 Sikes. | ac ES ae Mee Tae | as, 26 1 | 102

36 5 13:) 4143) 2° | 8).9 lc od Wee 2 |. 15| 3 1 |150

150—50 21 p 7 = = RE CCG deh 6|.. .. | 30

150—100 | 212 a) ow lick SOE ile. oe eee OTe

200—100 | 218 ee a eee ar ie) || el ae te eae Hic

210 Se EVE, 6| 4 VA ee ed tease Sy |B

26 e a: re era | be || a ale al Rey!

34h 3 1 ee ee Vlei) oa ea 9) 5. .. | 28

35 m mi a | eee eH 8: || 5.2 a= as eaaeile 48

35 n 13 1 = cl angel ogee RLERNH MDE |lnote 10:1... "| 52

35 t z 3 , ill aa a or Slog

250—150 | 350 5 2 eee Te ce ee Lith = ehS

35 p DO eel il ieee 7 ee en Fat a ale eee

5 GA Meetae| Peta (tage Bal een Nr” i Wes ii] ae ae eae S| ali

200 | Ae |...) 1) 2) 1) 8 9 90 | ae 1, el} eth. llc eee

Brame | meglincd. 2 a saul aa lee : 1 ail abt

351 x 1 of et Gales a ~ fea

400—300 | 21% | 2].. Sal Ce ee eel ee a he | 88

7 | RR | a Oa re ee 8 | a ee | seal ae]

Ci er ae lees oe Ls dee AMR ets |) Ue} LI)... elo

Bh Oya aloe ieee ie eas ae ce [Gebel alle altel) ol Ra (oY

Siero) WOOD gael a ol a 2 1 2 lean ee Iie coals

aco tae V8) a) BR egel.. Siig 5 8 id ea o | 38

30% Wiesel ie | 2 eee 1 5 ere 3 _| 12

Bie | Soe 14 | 4 | ¥ 3 oe 2 2 38

34f | 4]6 [12] 2] 1 Olde) eee |e | 8 56

1000—750 | 23a Alea | 2 Dilek Wid She. 20

3ld | 1 1 2 2 8

32 regia i és 3 6

ee MOMAD Hci lt ty ieee ner eae! | Bb DL) os]. bad 8

RRM ei | |. ll iw Aces leaker EER [a |e feces [owe fieectera d od

O76 ail tia ehrak ; Se lieantalliie Ba leesenilinsse Ve crieh ff mie J se |fats fl eter fia 1

31 ¢ 1 4

1500—1250 | 25f

30% 2 1 bas 1 2 7

2000—1500 | 25 ¢

26 b ee 1

314 BISCAYAN PLANKTON: THE OSTRACODA.

Puate 16.

Concua@cia AmMeETRA, Miiller.

Male. Stage II. Fig. 1. Shell, 3-0 mm.

2. Frontal organ, 3°0 mm.

3. Distal end of armature of principal bristle of antenna i., 3°] mm.

4. Pad on proximal accessory bristle of antenna i., 3-2 mm.

5. Hook-joint and neighbouring structures of inner limb of right

antenna 11., 3°l mm.

6. Hook-joint of left antenna ii., 3°1 mm.

7. The rostra viewed from inside, 30 mm.

Stage III. 8. Shell, 2°3 mm.

9. Frontal organ, and end of antenna i., 2°2 mm.

Stage IV. 10. Frontal organ, 1°6 mm.

11. Inner joint of antenna ii., 1:6 mm.

Female. Stage II. 12. Shell, 3°55 mm.

13. Frontal organ, and end of antenna 1., 3°5 mm.

i4, Inner joint of antenna ii., 3°5 mm.

Stage III. 15. Shell, 2:3 mm.

16. Frontal organ, and end of antenna i. (the dorsal bristle not

shown), 2°3 mm.

17. Inner joint of antenna 11., 2°3 mm.

Stage IV. 18. Shell, 1:5 mm.

19. Frontal organ, and end of antenna i., 15 mm,

Concua@cra BRAcHYAsKos, Miller.

Male. Older stage. Fig. 20. Shell, 1:2 mm.

21. Tooth of armature of antenna i.

Younger stage. 22. Frontal organ, 0°9 mm.

23. Inner branch of antenna i., 0°9 mm.

4. Shell, 1-4 mm.

. Frontal organ, 1-4 mm. ; antenna i. accidentally displaced.

RSG

Female. Older stage.

cw)

oO oO

. Inner branch of antenna i1., 1:2 mm.

. Shell, 0°8 mm.

Frontal organ, 0°9 mm.

Younger stage.

@°

www wo

“NI

Frontal organ, 0°8 mm.

Fow Len. DAN Sealine SOC. SHR 2) ZOOL, WO, x. Pi. 46:

a DB

s ~

25 <<

235 26

SSS ee

28 26:5 ae 27

G. H, Fowler del. Grout se

BISCAYAN OSTRACODA.

SECOND SERIES.—ZOOLOGY, VOL. X. 50

316 BISCAYAN PLANKTON: THE OSTRACODA.

Puate 1%.

Concuacia curta, Lubbock.

Male. Stage I. Fig. 30. Shell, 1:02 mm. (stigmatica stage).

31. Frontal organ, 1:0 mm.

32. Armature of principal bristle of antenna i., 1:0 mm.

33. Inner joint of right antenna ii. (one basal and one central bristle are

obscured by their fellows), 1:0 mm.

34. Hook of left antenna 11., 1:0 mm.

Stage II. 35. Shell, 0°32 mm. (curta stage).

36. Frontal organ, and part of antenna 1., 0°75 mm.

37. Inner joint of right antenna 11., 0°8 mm.

38. Hook of left antenna ii., 0°8 mm.

Earlier stages. 39. Shell, 0°82 mm. (before acquirement of secondary sexual characters).

40. Shell, 0°59 mm.

41. Frontal organ, and part of antenna 1., 0°59 mm.

42. Inner branch of antenna 11., 0°59 mm.

Female. Stage I. 43. Shell, 1:01 mm. (stigmatica stage).

44. Frontal organ, and part of antenna i., 1:01 mm.

45. Frontal organ, 1:01 mm.

46. Frontal organ, 1:01 mm.

47. Distal sense-tube of antenna u., 1:01 mm.

Stage II. 48. Shell, 0°80 mm. (curta stage).

49. Frontal organ, and part of antenna 1., 0°8 mm.

. Shell, 0°59 mm.

. Frontal organ, and part of antenna 1., 0°59 mm.

j=)

Earlier stages.

or Ot ox

—

co)

Frontal organ, and part of antenna i., 0°57 mm.

Shell, 0:45 mm.

Shell, 0°39 mm.

or Ot

Pes

Concua@cia DAPHNOIDES, Claus.

Male. Stage I. Fig. 55. Shell, 2°3 mm.

Female. Stage III. 56. Shell, 1:2 mm. :

57. Frontal organ, and part of antenna 1., 1-2 mm.

ConcH@CIA ELEGANS, Sars.

Male. Stage. II. Fig. 63. Postero-dorsal angles of the shell from inside.

Female. Stage III. 71. The same.

Fow er.

G, H. Fowler del.

TRANS. LINN. SOC. SER. 2, ZOOL. VOL. X. Pl. 17.

9)2, 63

BISCAYAN OSTRACODA.

50*

318

Male.

Female.

Male.

BISCAYAN PLANKTON: THE OSTRACODA

Stage II.

Stage III.

Stage IV.

Stage II.

Stage III.

Stage IV.

Stage V.

Stage I.

Stage II.

CoNcH@CIA ELEGANS, Sars.

Fig. 58.

59.

60.

61.

62.

64.

65.

66.

67.

68.

69.

70.

125

Concna@cia nappont, Brady and Norman.

Fig. 73.

75.

Puate 18.

Shell, 1:1] mm.

Frontal organ, 1-1 mm.

Shell, 0°9 mm.

Frontal organ, and antenna 1., 09 mm.

Frontal organ, 0°9 mm. a

Shell, 0°6 mm. i

Shell, 1-1] mm.

Inner branch of antenna ii., 1-1 mm. “1

Shell, 0°9 mm. re:

Frontal organ, and end of antenna 1., 0°8 mm.

Frontal organ, 0°83 mm,

Shell, 0°6 mm.

Shell, 0-4 mm.

Shell, 2:1 mm.

Shell, 1:0 mm.

Fow er. TRANS. LINN. SOC. SER. 2, ZOOL. VOL. X. P. 18.

G. H, Fowler del.

BISCAYAN OSTRACODA.

Male.

Female.

Male.

Female.

Stage I.

Stage III.

Stage I.

Stage III.

Stage LV.

Stage V.

Stage I

Stage II.

Stuge TWO

BISCAYAN PLANKTON: THE OSTRACODA.

PLATE 19.

Concna@cia HADDONI, Brady and Norman.

74. Inner branch of antenna 1i., 2°1 mm.

76. Frontal organ, and part of antenna 1., 1:0 mm.

77. Inner branch of antenna ii., 1°0 mm.

78. Shell, 2°8 mm.

79. Shell, 16 mm.

80. Frontal organ, and part of antenna 1., 1°6:mm.

81. Inner branch of antenna i., 1°6 mm.

82. Shell, 1:0 mm.

83. Frontal organ, and part of antenna 1., 1:0 mm.

84. Inner branch of antenna 11., 1:0 mm.

85. Shell, 0°7 mm.

87. Inner branch of antenna i1., 0°'7 mm.

88. Shell, 0-4 mm.

89. Frontal organ, 0°4 mm.

rot

j}. Frontal organ, and part of antenna i., 0°7 mm.

ConcH@CIA HYALOPHYLLUM, Claus.

Fig. 90. Shell, 2°3 mm. (/ophura stage).

91. Frontal organ, 2°3 mm.

92. Inner branch of right antenna i., 2°3 mm.

93. Shell, 1:5 mm. (4yalophyllum stage).

94. Frontal organ, 1°5 mm.

95. Inner branch of right antenna 1., 1°5 mm.

96. Hook aud surrounding structures of left antenna 1.

98. Shell, 1-1 mm.

100. Sheli, 0°7 mm.

101. Frontal organ, 0°77 mm.

102. Shell, 2°5 mm. (lophura stage).

105. Shell, 1:7 mm. (hyalophyllum stage).

108. Shell, 1:0 mm.

Fow er. TRANS. LINN. SOC. SER. 2, ZOOL. VOL. X. Pl. 19.

92 95 100

G. H. Fowler del.

BISCAYAN OSTRACODA.

Male.

Female.

Male.

Female.

Male.

Female.

Male.

Female.

BISCAYAN PLANKTON: THE OSTRACODA.

Stage II.

Stage ITI.

Stage I.

Stage II.

Stage III.

Stage II.

Stage IIL.

Stage IV.

Stage II.

Stage III.

Stage IV.

Stage V.

Stage ?II.

Stage ? IIT.

Stage ?II.

Stage I.

Stage II].

Stage 1.

Stage IT].

PLATE 20.

CoNncH@CIA HYALOPHYLLUM, Claus.

Fig. 97

. Opening of left lateral gland, from inside, 1°5 mm.

99. Frontal organ, and end of antenna i., 1:1 mm.

103. Frontal organ, and part of antenna i., 2°5 mm.

104. Part of inner branch of antenna ii., 2°5 mm.

’

106. Frontal organ, 1°7 mm.

107. Central bristles of inner branch of antenna il., 1°7 mm.

109. Frontal organ, and end of antenna i., 1°0 mm.

D5 a >

Concue@cra imBricara (Brady pars), Miller.

Fig. 110. Hook and bristles of antenna 1., right side, 2°0 mm.

111. Hook of left side, 2°0 mm,

112. Shell, 15 mm.

118. Shell, 1:0 mm.

114. Frontal organ, and end of antenna i., 1°0 mm.

115. Frontal organ, and end of antenna i., 2°5 mm.

116. Part of antenna i., 2°5 mm.

117. Shell, 1:5 mm.

118. Frontal organ, and end of antenna i., 1°5 mm.

119. Shell, 1:0 mm.

120. Frontal organ, 1-0 mm.

121.

Concu@cta 1NERMIS, Claus.

Fig. 122.

123

Shell, 0°6 mm.

eee

Shell, 1:9 mm. |

. Shell, 1°5 mm.

124. Frontal organ, and part of antenna i., 1:5 mm.

125. The rostra, from inside, 1°5 mm.

126. Right shell, from inside, 2°0 mm.

Fig. 128

129

132

133

135

138

oONCH@cIA LoricaTa, Claus.

. Frontal organ, 2-4 mm.

. Armature of antennai., 2°4 mm.

. Frontal organ, 1-4 mm.

. Inner branch of antenna il., 14 mm,

. Inner branch of antenna 1., 2°6 wm.

. Frontal organ, and end of antenna i., 1°2 mm.

Fow er. TRANS. LINN. SOC. SER. 2, ZOOL. VOL. X. Pl. 20,

22 Vln 129

125

126

G. H. Fowler del. BISCAYAN OSTRACODA. Grout se,

SECOND SERIES —ZOOLOGY, VOL. X. 51

324

Male.

Female.

Male.

Female.

Male.

Female.

Male.

Stage I. Fig.

Stage II.

Stage IIL.

Stage I.

Stage II.

Stage ILI.

Stage I, Fig.

Stage II.

Stage III.

Stage I.

Stage II.

Stage III.

Stage IV. Fig.

Stage V.

BISCAYAN PLANKTON: THE OSTRACODA.

127.

130.

131.

166.

PLATE 21.

ConcH@cia Loricata, Claus.

Shell, 2-4 mm. (ctenophora stage).

Shell, 1-5 mm. (loricata stage).

Shell, 1-4 mm. (antero-dorsal region slightly distorted, owing to

repeated opening).

. Shell, 2°6 mm, (cfenophora stage).

. Shell, 2°0 mm. (/oricata stage).

Shell, 1:2 mm.

ConcHa@cra MAGNA, Claus.

. Shell, 3-0 mm. (macrocheira stage).

. Frontal organ, 2°8 mm.

. Armature from about the middle of the toothed part of the principal

bristle of antenna 1., 2°9 mm.

. Hook of antenna ii., right side, 2°8 mm.

. Central bristles of the inner branch of antenna ii.; the hairs were very

long, but are much foreshortened, 2°8 mm. ‘

|. Shell, 1:8 mm. (magna stage).

. Shell, 1°3 mm.

. Shell, 3°3 mm. (macrocheira stage).

. Shell, 1°9 mm. (magna stage).

. Shell, 1:2 mm.

Tue A Larva.

. Shell, 0°9 mm.

164.

Shell, 0°9 mm.

Shell, 0°5 mm.

Fow er. TRANS. LINN. SOC. SER. 2, ZOOL. VOL. X. Pl. Phe

ler 161

2 4

150 /44 .

151 P 166

134 LF

ae 142

136 154

157 158

G. H. Fowler del. BISCAYAN OSTRACODA. Grout se.

326 BISCAYAN PLANKTON: THE OSTRACODA.

PLaTE 22.

Concnua@cia Magna, Claus.

Male. Stage II. Fig. 145. Frontal organ, 1-8 mm.

146. Armature from about the middle of the toothed part of the principal

bristle of antenna 1., 1°8 mm.

147. Hook of antenna 11., right side, 1:8 mm.

148. Central bristles of the inner branch of antenna i1., the hairs foreshortened

on one side.

Stage III. 150. Frontal organ, usual form, with sharp terminal spike, 1:3 mm.

Female. Stage I. 152. Part of dorsal bristle of antenna i., 3°4 mm.

153. Central bristles of inner branch of antenna 1i., 3°4+ mm.

Stage II. 155. Frontal organ and end of antennai., the bristles and tubes cut short.

The dorsal bristle accidentally omitted, 1°9 mm.

156. Part of the dorsal bristle of antenna i., 2°] mm.

157. Central bristles of the inner branch of antenna ii. The shorter does

not always show hairs, 2:1 mm.

Stage III. 159. Frontal organ of usual form, and antenna i. carrying a hairless, very

fine dorsal bristle, 1:2 mm.

160. Central bristles of inner branch of antenna ii., 1:2 mm.

Tue A Larva.

Male. Stage IV. Fig. 162. Frontal organ, and part of antenna i., 0-9 mm.

163. Central bristles of antenna ii., 0°9 mm.

Female. Stage IV. 165. Frontal organ, 0°8 mm.

Male. Stage V. 167. Frontal organ, and part of antenna i., 0°5 mm.

168. Central bristle of antenna ii., 0°5 mm.

Concua@cra procera, Miiller.

Male. Stage Il. Fig. 169. Shell, 1-1 mm.

Stage ILI. 170. Shell, 0°9 mm.

171. Frontal organ, 0°9 mm.

172. Inner branch of antenna ii., 0°9 mm.

Stage IV. 173. Shell, 0-6 mm.

174. Frontal organ, and part of antenna 1., 0°6 mm.

Female. Stage IL. 175. Shell, 1:2 mm.

176. Frontal organ, somewhat like that of brachyaskos, 1:2 mm.

Stage III. 177. Shell, 0°9 mm.

178. Frontal organ, and part of antenna i., 0°9 mm.

Stage IV. 179. Shell, 0°7 mm.

180. Frontal organ, and part of antenna 1., 0°7 mm.

181. Inner branch of antenna ii., 0°7 mm.

Stage V. 182. Shell, 0°S mm.

183. Frontal organ. 0°5 mni.

CoNCHGCIA PUSILLA, var. MAgor, Miiller.

Male. Fig. 184. Shell, 0°8 mm.

Female. 186, Shell, 0°38 mm.

Fow ier. TRANS. LINN. SOC. SER. 2, ZOOL. VOL. X. Pl. 22.

145

li7

186 184

BISCAYAN OSTRACODA.

G. H. Fowler del.

328

BISCAYAN PLANKTON : THE OSTRACODA.

Male.

Female.

Male. Stage II

Stage ITI.

Stage IV.

Female. Stage II.

Stage III.

Stage IV.

Stage V.

Male. Stage I.

PLATE 28.

CoNCHGCIA PUSILLA, var. MAJOR, Miiller.

Fig. 185. Inner joint of antenna 11., 0°7 mm.

187.

Postero-dorsal angle of shells, from inside, 0°8 mm.

Concua@cta RHYNCHENA, Miiller.

. Fig. 188.

Stage II.

Stage III.

Stage IV.

Female. Stage I.

Stage II.

Stage III.

Stage LV.

Fig.

189.

190.

NEN.

192.

193.

194.

195.

196.

197.

198.

GK)

200.

201.

202:

203,

204.

Shell, 2°5 mm.

Pad on proximal accessory bristle of antenna i., 2°5 mm.

Shell, 1:7 mm.

Frontal organ, and part of antenna i., 1°7 mm.

Shell, 1:1 mm.

Frontal organ, and end of antenna 1., 11 mm.

Part of antenna 11., 1-1] mm.

Shell, 2°5 mm.

Frontal organ, with unusually blunt end, 2°5 mm.

Frontal organ, with unusually sharp end, and end of

antenna 1., 2°5 mm,

Frontal organ with prolonged tip, 2°4.

Shell, 1:6 mm,

Frontal organ, and end of antenna i. (dorsal bristle accidentally

omitted), 1:6 mm.

Shell, 1-1 mm.

Frontal organ, and end of antenna i., 1:1] mm.

Shell, 0°8 mm.

Frontal organ, and end of antenna 1., 0°8 mm.

Concuecia rotunpata, Miller.

206.

208.

209.

210.

212.

214.

216.

217.

218.

220.

222.

224.

Inner branch of right antenna ii., 0°9 mm.

Frontal organ, and part of antenna i., 0°77 mm.

Inner branch of right antenna ii., 0°7 mm.

Inner branch of left antenna 11., 0°8 mm.

Frontal organ, and part of antenna i., 0°6 mm.

Frontal organ, and part of antenna i., 0-4 mm.

Frontal organ, typical form, 1°2 mm.

The same, unusual form, resembling that of pusid/a, 0-9 mm.

Inner branch of antenna ii., 1*2 mm.

Frontal organ, and part of antenna i., 0°83 mm.

Frontal organ, and part of antenna i., 0° mm.

Frontal organ, and part of antenna i., 0°3 mm.

Fow.nr. TRANS. LINN. SOC. SER. 2, ZOOL. VOL. X. Pl. 23.

19] a

188

190

192

195 ee

200 2/4

i an ws if y

206 209 218

BISCAYAN OSTRACODA.

205

G. H. Fowler del.

530

Male.

Female.

Male.

Female.

Male.

Female.

Stage I.

Stage II.

Stage III.

Stage IV.

Stage I.

Stage IT.

Stage III.

Stage IV.

Stage II.

Stage ILI.

Stage IV.

Stage II.

Stage III.

Stage IV.

Stage I.

Stage II.

Stage III.

Fig.

BISCAYAN PLANKTON: THE OSTRACODA.

wm ww Ww

www weve

oan me

w vo

oo 9

PLATE 24,

Concnacia Rorunnata, Miller.

Shell, 1-0 mm.

. Shell, 0'7 mm.

. Shell, 0°58 mm.

3. Shell, 0-4 mm.

5. Shell, 1-1] mm.

. Shell, 0°38 mm.

. Shell, 0°5 mm.

. Shell, 0°3 mm.

Concn@cra sPrInirEeRA, Claus.

. Shell, 1:8 mm.

. Shell, 1°4 mm.

. Frontal organ, and part of antenna 1, 1-4 mm.

. Shell, 1:0 mm.

. Frontal organ, and part of antenna i., 1:0 mm.

. Shell, 2:2 mm.

. Inner branch of antenna ii., 2°2 mm.

. Shell, 1:4 mm.

. Frontal organ, and part of antenna 1.

. Shell, 1:0 mm.

. Frontal organ, and part of antenna i., 1:0 mm.

ConcCH@CIA SPINIROSTRIS, Claus.

. Frontal organ, 1:3 mm.

. A saw-tooth of the principal bristle of male antenna i. (freehand), _

1:3 mm.

. Frontal organ, 1-0 mm.

. Inner branch of right antenna u1., 1:0 mm.

. Inner branch of left antenna u., 1°O mm.

. Frontal organ, and part of antenna i., 1°2 mm.

46. Frontal organ, and part of antenna i., 0°38 mm.

Fow er. TRANS. LINN. SOC. SER. 2, ZOOL. VOL. X. IP 2a:

205 Se 225

207 219 226

ine)

it |

Ls)

> Za = 250

2F4 a mae

— aa) L ee

242 246 ca ie 234

. H. Fowler del. BISCAYAN OSTRACODA. Grout sc.

SECOND SERIES,-—ZOOLOGY, VOL. X. 52

3o2 BISCAYAN PLANKTON: THE OSTRACODA.

PLATE 25,

ConcHa@cra sPINrRostTRIS, Claus.

Male. Stage I. Fig. 286. Shell, 1°3 mm.

Stage II. 239. Shell, 1:0 mm.

Female. Stage II. 24.3. Shell, 1:2 mm.

Stage III. 245. Shell, 0°7 mm.

ConcH@cia ZETESIOS, Sp. Nl.

Female. Stage (?)I. Fig. 247. Shell, 2-4 mm.

248. Frontal organ, and end of antenna 1., 2°3 mm.

249. Frontal organ, from another specimen, 2°4 mm.

250. Part of dorsal bristle, 2°3 mm.

251. Inner branch of antenna 11., 25 mm.

Stage (7) II. 252. Shell, 1-5 mm.

258. Frontal organ, 15 mm.

Concnecia B.

Fig. 254. The right shell, 1:7 mm.

255. The left shell.

256. Frontal organ, and part of antenna i.

257. Inner joint of antenna il.

Concuacra C.

Fig. 258. Shell, 1-1 mm. (rostrum slightly “vestored”’).

259. Frontal organ.

260. Pad on accessory bristle of antenna 1.

261. Inner branch of right antenna il.

262. Inner branch of left antenna ii.

Haxrocyrris GLososa, Claus.

Male. Stage I. Fig. 263. Shell, 2:1 mm. The “ pecked ” line completes what

is believed to be the natural contour.

Fow er,

»®

236

£359

2F5

G. H. Fowler del.

TRANS. LINN. SOC. SER. 2, ZOOL. VOL. X. Pl. 25.

{1s

25] 247

25F

BISCAYAN OSTRACODA.

334

BISCAYAN PLANKTON : THE OSTRACODA,

Male. Stage I. Fig. 264.

Female.

Stage II.

Stage ITI.

Stage IV.

Stage V.

? Female. Stage IV.

265.

}. Hook of right antenna ii.

WO Ww WO ® wv

a Ue aS Sy oes URS

NEO oF © oo

Fig. 279.

280.

281.

GicanTocyeris PrLLuctpA, Miller.

Fig. 282. Embryo of 2:1 mm. in length, showing five pairs of appendages.

. Inner branch of left antenna u1.

. Shell, 2:7 mm.

. Frontal organ, and part of antenna 1., 2°50 mm.

. Frontal organ, 2°5 mm.

1. Shell, 1:6 mm.

. Inner branch of antenna i1., 1°7 mm.

. Shell, 0-9 mm.

4, Shell, 0°6 mm.

5. Left shell, from the ventral border, 0°6 mm.

. Frontal organ, and part of antenna i., 0°6 mm.

. Inner branch of antenna i., 0°6 mm.

278.

PLATE 26.

Hatocyrris GLoposa, Claus.

Frontal organ and antenna 1.

Frontal organ.

Shell, 0-4 mm.

Cypripina castanga, Brady.

Shell, 1°8 mm.

Shell, from inside, to show the deeply ventral position of the rostrum.

The rostral region.

The edges of the shell have grown markedly downwards in the

anterior part (sh).

27/1

Elo

274

278

G. H, Fowler del.

SECOND SERIES.—ZOOLOGY,

TRANS. LINN. SOC. SER. 2, ZOOL. VOL. X. Pl. 26.

Gy 266

264 K

269

265

, A

( bo C76

270

ers

279

BISCAYAN OSTRACODA. Grout se.

VOL. xX. 53

336 ~BISCAYAN PLANKTON: THE OSTRACODA.

PLATE 27,

captured. The lower part represents the author’s interpretation of the observed facts.

~ explanation, see pages 298, 299.

27.

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BISCAYAN PLANKTON.

Part XIII.—THE SIPHONOPHORA.

By Henry B. Biertow, Uuseum of Comparative Zoology, Cambridge, Mass.

(Communicated by G. Hersert Fowter, Ph.D., F.L.S.)

(Plate 28.)

Read 3rd November, 1910.

List oF Spxctzs.

Page

UGG UECE GOGH UU REN Se che eyeoeiin o's :4. aac Cee MRR et elo eS le ace Heo arsusrejolamelee 340

JASEOAT (NICHI Conte a ODA BC ECEEORTE CCC 6.0.00. 0 BO COE ACIS O CU REDO OSD 341

IVGDEYES SLUTS G 66 SB OCOe BRODER’ 50.00.0010 0 OG BEC Rae OOTOLIC 343

ID DOGS CHV MULT, ooo BOOM Ee OSS cho Ska be DORR EB OUDOOOODOOD 344

DIDI esu OW LOrIME Ds TLOV Ss <n «o's. +s. s, as Stee te ee Bas wo 5 es sie) Sin eistere bis 346

CGH ck EE 00 nnn: 0) Se 348

! ESD RO TORR TEN Ug OS CRORE ROR REO 20 SOC OCLC CODER SEE OUe HO 350

OG EOE: FICO DIU) Ue ci RERROEROIIC Fe o-& G0 6 OE oO REE OIE ere 351

Ye VOGHED GEE Oa USD OIE eC Ccc b> 3. C OOK REE SE aEEa nee 351

FRIBYZQD BV SIGAS PECIES.ehaciais;cie)<. «+ s:o-9 a.dc 0) ROMER Tre oe 6 creel eral ewes ayaa 352

BauyneuercalMMIstrIpUbIOM: .. ... «os s\sicsa slepeldeptenetersistels crs sic elt wie) #16 elate/el oie 352

DID OPT AD Hipp eyetaye st cFalafsis\s. 2 « ss, 21x 47st aeRO wl aneve eavaials! sjaie'sivi gd 355

Excert for a single unrecognizable rhizophysid fragment the collection consists

exclusively of Calycophoree. A similar absence of the Physophorz in the Atlantic

during the summer has been noted by Chun (1897 0), who has suggested that either

the adults or the larvee must be at considerable depths at this time of the year. The

Biscayan collection throws no light on this question, since no larval physophorids were

taken, in spite of the considerable number of hauls from comparatively great depths.

The scarcity of physophorids is not a phenomenon common to the whole of the North

Atlantic during the summer months, for, along the eastern coast of North America, it

is during this season chiefly that they are encountered.

On geographical grounds the records are valuable, because very few siphonophores

have ever been recorded from the Bay of Biscay, and because several were captured

in closing-nets.

The most interesting features of the collection from the systematic standpoint are a

new species of Déiphyes, and a new genus, Nectopyramis, probably belonging to the

Monophyide, but easily distinguished by structural features.

The classification followed in the ensuing pages is that proposed by Chun (1897 3),

and since adopted by Lens and Van Riemsdijk (1908). For a very different scheme,

see K. C. Schneider (1898). All the species here listed, with the single exception of

SECOND SERIES.—ZOOLOGY, VOL. x. 54

338 MR. HENRY B. BIGELOW—BISCAYAN PLANKTON:

Nectopyramis thetis, are contained in the ‘ Albatross’ Eastern Pacific Expedition ; and

in my report on that collection, now in press, they are more fully described and figured,

and questions of synonymy and classification are discussed in greater detail than the

scope of the present paper allows.

In conclusion, I may say that the excellent condition of the specimens, upon which

Dr. Fowler is to be congratulated, have made their study much easier than is usually

the case with preserved Siphonophores.

CALYCOPHOR A.

MONOPHYIDA, Claus, 1874.

SPH HRONECTIN & (Huxley, 1859), Haeckel, 1888.

NECTOPYRAMIS, gen. nov.

A single nectophore, apparently a monophyid, differs in so many important features

from all known Calycophore that it has been made the type of a new genus. Necto-

pyramis is also represented in the ‘ Albatross’ collection by a considerable series. When

I first examined the specimen I thought, from the appendages, that it might prove to

be the polygastric state of the eudoxid described by Chun (1888, 1897 6), Bedot (1904),

and Lens and Van Riemsdijk (1908) as Ceratocymba. But the bract, though in some

respects suggesting that form, differs so much from it in the structure of its somatocyst

as to forbid the union. And I may forestall my account of the ‘ Albatross’ collection

by adding that it shows strong evidence connecting Ceratocymba with Abyla leuckartu,

a union the possibility of which has already been suggested by K. C. Schneider (1898).

So far as we can judge from the single available example, Nectopyramis may be

defined as Monophyide with rounded nectophore, with the somatocyst represented by a

series of divergent canals: the cormidia are without special nectophores.

NECTOPYRAMIS THETIS, sp. nov. (PI. 28. figs. 1-4.)

Occurrence: 800 to 0 fathoms. 386%. 1 specimen in excellent condition.

Nectophore——The nectophore, which is 11 mm. in greatest length, is of a pyramidal

form, so characteristic that it makes the animal noticeable at the first glance. It may

be described as bounded by four equilateral triangles, with somewhat concave margins ;

but these triangles are hardly comparable to the facets of the cymbonectids or diphyids,

because they join each other by gradual curves, instead of being separated by sharp

ridges. In this regard, then, the general form is intermediate between that of such

forms as Spheronectes and Halopyramis. The gelatinous substance of the nectophore

is stil, but almost perfectly transparent.

The nectosac lies in one of the triangular faces, near its dorsal angles. It is

comparatively small, shallow, and saucer-shaped, and its subumbrellar surface, though

torn, is sufficiently well preserved in places to show that its musculature, like that of

Hippopodius, is so weak that it cannot serve as a very effective swimming-organ. The

hydreecium is large, deep, and laterally compressed. It is situated immediately above

the nectosac. Its opening lies along the line of junction between two of the facets, and

THE SIPHONOPHORA. 339

extends from end to end of the nectophore. The relationship of nectosac to hydreecium,

and the form of the latter, can best be seen in the accompanying photographs (figs. 1, 2).

The typical somatocyst of other monophyids is here represented by a series of canals,

which form not the least interesting feature of the nectophore, and suggest the

condition in Stephanophyes superba, Chun (1891). The arrangement of the canals is as

follows :—from the point on the inner surface of the hydrecium where the stem is

attached, a canal runs on either side over the inner lateral surface of the hydrecium, to

terminate blindly before reaching its ventral margin. Each of these canals, at a point

nearly opposite the dorsal margin of the nectosac, gives off a branch which runs in a

direct line to the dorso-lateral angle of the nectophore. The ascending branch,

corresponding in location to the ascending branch of the somatocyst of Rosacea and

Praya, is so much injured that it is impossible to tell how far it extended normally. In

the specimen it can be traced about halfway to the apex of the hydrecium. The

descending branch, after giving off the trunks to the lateral walls of the hydreecial

cavity, follows the dorsal margin of the hydreecium, as in the Prayinze ; but instead of

connecting with the nectosac by a single canal, as is usually the case, it sends no less

than four to that structure. These canals, clearly seen in the photographs, are a pair

of laterals, arising together, a dorsal and a ventral each arising separately, opposite the

dorsal or ventral margin of the nectosac, as the case may be. The canals do not join

the nectosac at its apex, but about at its mid-level. But in spite of their unusual

arrangement, they no doubt correspond to the radial subumbral canals of more typical

forms. In its further extension the descending branch of the somatocyst reaches nearly

to the ventro-basal angle of the nectophore.

Stem and Appendages——The stem is very much contracted, but when detached from

the nectophore the following features could be determined. There are no buds for

reserve bells, nor could I distinguish any structure suggesting that a second bell had

been attached, but had been lost. 'The evidence of a single example, so contracted as is

this one, is perhaps insufficient to make it certain that the species isa monophyid. But

so far as it goes it is positive, and unless other specimens are found with posterior

nectophores, or with the buds for such structures, no course is open except to refer

Nectopyramis to the Monophyidee. Besides a considerable number of very young

appendages and buds, there is one group in which siphon, tentacle, two gonophores, and

bract are well developed.

The bract is very characteristic. In general form it is saucer-shaped, or scale-like,

bluntly pointed at the superior, transversely truncate at the inferior end. Though

flat, there are three dorsal ridges, a single descending and two ascending, and near the

centre, where the latter arise, there are two triangular prominences. The canal system

of the bract consists of a single descending, and two diverging lateral branches, each of

which gives off a short, nearly vertical branch running up into one of the dorsal

prominences.

It thus resembles even to minor details the canal system of the bract of Praya

cymbiformis, so often described and figured, and, though less closely, that of Rosacea

_plicata.

54*

One of the gonophores is already of comparatively large size, and has a well-marked

hydrecial groove, limited by broad wings, but open as yet throughout its length.

Except for these wings, the surface of the gonophore shows neither ridges nor distinct

facets, nor are there any basal teeth. But the absence of such structures at this early

stage does not necessarily imply that they are not developed later.

The spadix is extremely small—indeed, it is nothing more than a minute knob

projecting downward into the bell cavity; at this early stage its sex could not be

determined.

In addition to this gonophore there are two younger ones in the single cormidium

preserved; both are very young, but one has a well-developed manubrium on which

ova, already of considerable size, can be distinguished. In this cormidium there is no

special nectophore ; but it can only be settled on more extensive material whether such

organs are developed later or not.

The siphon, which is relatively large and has a well-marked basigaster, presents no

feature of special interest.

The basal part alone of the tentacle is still intact, and the numerous tentillz which

are attached to it are all immature. So far as their present state shows, they are of the

type characteristic of Spheronectes and other monophyids.

Assuming that Nectopyramis is a monophyid, it does not fit in very well with either

of the two subdivisions of that group usually recognized, for although, so far as the

form of the nectophore is concerned, it agrees well enough with the Spheeronectine, it

differs from that subfamily, and from the Cymbonectinz as well, in the structure of the

somatocyst. In this respect the only close parallel among Calycophore is afforded by

certain Diphyide, e. g. Stephanophyes, Chun. But the absence of any trace of a

posterior nectophore forbids classing it in that family. To make further speculation as

to its affinities of any real value, large series must be examined, to determine especially

whether more than one nectophore is ever present.

CYMBONECTINA, Haeckel, 1888.

Mvueera#a, Busch, 1851.

Mueerma Kocutt (Will), Chun.

Diphyes kochii, Will, 1844, p. 77, Taf. 2. fig. 22; Busch, 1851, p. 46, Taf. 4. figs. 3-5.

Muggiea pyramidalis, Busch, 1851, p. 48, Taf. 4. fig. 6. :

Mugyiea kochii, Chun, 1882, p. 679, Taf. 16. figs. 1-7; 1892, p. 89; K. C. Schneider, 1898, p. 88.

For a complete synonymy of this species and its eudoxid, the Ersea pyramidalis of

Will, see Chun, 1892, p. 89.

Occurrences: 50 to 0 fathoms. 25g. 10 anterior nectophores.

100 to 0 fathoms. 30 9, 3506, 360, 36e. 11 4 K

150 to 0 fathoms. 36. 3 0 »

200 to 0 fathoms. 36g. A » 99

250 to 0 fathoms. 36h. 2

9 33

All about 12 mm. long.

These nectophores, none of which are in very good condition, agree, on the whole, so

THE SIPHONOPHORA. 841

well with Chun’s (1882) description and figures of Muggiea kochii that I have no doubt

that they belong to that species; the more so since in none of them was any trace of a

posterior nectophore, or of a bud for such a structure, to be seen.

As Will (1844), Busch (1851), and Chun (1882) have all observed, the nectophore is

pyramidal, with five prominent ridges, but with nothing more pronounced in the way of

basal teeth than a slightly prominent dorsal ridge. One feature not mentioned by

earlier students is that the lateral ridges invariably end a short distance above the basal

margin. But since this fact is often masked by the incurving of the bell-margin, and

can be seen in contracted material only by flattening out this region, it may well have

been overlooked. In expanded specimens, particularly those in which the musculature

of the subumbrella is torn away; the course and termination of the ridges is easily

followed.

The somatocyst is cylindrical and reaches from one-third to one-half the height of the

nectosac. Its general form is one of the readiest field-marks to separate this species

from Diphyes fowleri, which resembles it in general appearance ; its shortness, together

with the shallowness of the hydreecium, which lies almost wholly below the level of the

opening of the nectosac, serve to distinguish WZ. kochii from WW. atlantica (Cunningham,

1892).

To Chun’s account I can further add that the dorsal wall of the hydrecium below

the level of the bell-opening is divided longitudinally into two nearly symmetrical wings,

as in many Diphyopsine.

In every specimen, all but the youngest appendages were wanting. WV. kochii has

already been recorded from the Atlantic (Chun, 1888), as well as from the Mediterranean.

But there is, so far as I know, no definite record of its occurrence so far north as the

Bay of Biscay.

DIPHYIDA, Eschscholtz, 1829.

PRAYIN4&, Kolliker, 1853.

Rosacea, Quoy et Gaimard, 1827.

RosacEa PLICATA, Quoy et Gaimard.

Rosacea plicata, Quoy et Gaimard, 1827, p. 177, pl. 48. fig. 4; K. C. Schneider, 1898, p. 78.

Rosacea ceutensis (partim), Blainville, 1834, p. 140, pl. 6. fig. 8.

Praya diphyes, Kélliker, 1853 a, p. 33, Tab. 9; 18534, p. 306; Vogt, 1854, p. 99, pls. 16, 17;

Bedot, 1882, p. 122 ; non Lesson, 1843, p. 144.

Diphyes brage, Vogt, 1851 4, p. 140.

Rhizophysa filiformis, Delle Chiaje, 1842, p. 135, pl. 149. fig. 3 ; Vogt, 1851 4, p. 522.

Praya filiformis, Keferstein und Ehlers, 1861, p. 20.

Lilyopsis diphyes, Chun, 1885, p. 280; 18976, p. 102; Haeckel, 1888, p. 150.

? Rosacea ccutensis, Quoy et Gaimard, 1827, p. 176, pl. 4d. figs. 2, 3.

This species, so fully described and well figured by Vogt (1854) and by Kélliker

(1853 a), is usually known as Lilyopsis diphyes (Vogt), Chun, but, as K. C. Schneider

(1898) has pointed out, there is good reason to believe that it is identical with the

Rosacea plicata found by Quoy and Gaimard in the Straits of Gibraltar. It is true that

342 MR. HENRY B. BIGELOW—BISCAYAN PLANKTON :

their figure, which is of the superior nectophore only, leaves much to be desired, but,

as Leuckart long ago observed, the species which they studied was undoubtedly a

Prayid ; while the presence of a globular swelling at the extremity of the somatocyst

points strongly to its identity with the P. diphyes of Vogt and Kolliker, rather than

with any other species of the subfamily. Nor is there anything in the original figure or

description to forbid the union of the two. It is, of course, most desirable to identify

the older and usually very insufficient figures and descriptions of Siphonophores with

the species actually known to-day, and it seems that in the present case this can be done

safely.

The name Praya diphyes was first used by Lesson (1843) [the quotation by Vogt of

Blainville, 1834, for this name is an error] for the Diphyes prayensis of Quoy and

Gaimard, a species founded for a single detached nectophore. It was regarded by Vogt

as identical with the species he studied. But Quoy and Gaimard’s figures (1834, pl. 5.

figs. 37, 38), so far as they go, agree better with P. cymbiformis.

Occurrences: 250 to 0 fathoms. 36h, 36%. 6 superior, 5 inferior nectophores.

300 to 0 fathoms. 36 k. 6 7 2 a i

350 to 0 fathoms. 36 1. 3 “4 3 - e)

1250 to O fathoms. 27 a. il a

300 to 200 fathoms. 21¢,26f. 2 vo aes x

The superior nectophores range from 12 mm. to 21 mm. in length, and from 9 mm. to

17 mm. in breadth; the inferior ones from 12 mm. to 22 mm. and from 7 to 15 mm.

respectively.

When the collection reached my hands all the nectophores here listed were separate.

The older [inferior] and younger [superior} ones, however, are not only easily identified,

but from their sizes can often be associated with each other in pairs. In all the

specimens the greater part of the corm and appendages are broken off, but in one I was

able to find a well-preserved special nectophore, in addition to many crowded gonophores,

siphons, tentacles, and the remnants of bracts. This discovery, of course, makes its

generic identification certain.

The specimens are identified with R. plicata (rather than with R. medusa, Metschnikoft

1870=R. diphyes, Graeffe, 1860=R. rosea, Chun, 1885), because of the absence of

tentacular rudiments on the margin of the special nectophore. Diagnostic also is

the comparatively small size of the nectosac, the short oval form of the nectophores, and

the presence of well-marked hydrecial furrows. In &. medusa, as clearly shown in the

figures by Metschnikoff (1870) and Bedot (1895), the chief nectophores are triangular,

the nectosaes relatively very large. <A single colony of R. medusa, from the Pacific,

which I have examined, agrees with these figures, in the almost total suppression of

the hydrecium. The two nectophores are merely slightly concave ventrally and

closely apposed to each other.

Comparison between the Biscayan specimens and excellently preserved material

of Praya cymbiformis, Delle Chiaje (=P. maxima, Gegenbaur), from both the Mediter-

ranean and the Pacific, shows differences in the forms of the younger (superior) of the

two chief nectophores, sufficient for identification, even if the stem be lacking.

THE SIPHONOPHORA. 343

In R. plicata the nectophore is short and broad, and the hydrecium, which is very

deep, occupies only about one-third of the ventral surface. In P. eymbiformis, however,

as is clearly shown in Gegenbaur’s (1854) excellent figures, the nectophore is propor-

tionately longer, and the hydroecium extends for its whole length, in the form of

a groove. When specimens of the two species are placed side by side, these differences,

which (though, of course, of minor importance) prove to be constant, are at once

apparent. [Compare also the figures of R. plicata (=P. diphyes) by Kélliker, 1853 a,

with those of P. cymbiformis (=P. maxima) by Gegenbaur, 1854. }

The terminal dilatation of the somatocyst in R&. plicata, lately mentioned as a specific

character by K. C. Schneider (1898), also proves to be constant. Although the

contraction of preserved material may obscure it, it is more or less prominent in all the

Biscayan specimens, and was observed and figured by Kolliker and by Vogt, as well

as by Quoy and Gaimard, but it has never been recorded, nor have I observed it, in

P. cymbiformis.

The appendages are too fragmentary to enable me to add to the earlier descriptions

of these structures noted above. In its form, the single special nectophore which was

still preserved agrees clearly with Vogt’s figures.

The inferior (older) nectophores are proportionately somewhat shorter and broader

than those of P. eymbiformis. The difference is so slight, however, that the two might

be easily confused in the absence of their respective superior nectophores. The form of

the hydrecium in R. plicata is well shown in Vogt’s figure (1854, pl. 16. fig. 3).

The entire absence of this species from any of the surface hauls, the comparatively

great depths of the hauls in which it was taken, and the positive evidence of its

capture in one closing-net haul between 300 and 200 fathoms, show that at least in the

Bay of Biscay, at the time of the expedition of the ‘ Research,’ it was a member of

the mesoplankton, not of the epiplankton. But, inasmuch as it has been recorded

previously from the surface on many occasions, its presence at a lower level cannot

be regarded as indicating an invariable habitat.

Drruyropsin@, Haeckel, 1888.

Dipuyss, Cuvier, 1830.

DIPHyEs suBTILIs, Chun.

Ersea elongata, Will, 1844, p. 82, Tab. 2. figs. 30, 31.

Monophyes irregularis (partim), Chun, 1885, p. 271, Taf. 2. fig. 3 (non Claus, 1874).

Monophyes gracilis (partim), Chun, 1885, p. 271, Taf. 2. fig. 5 (non Claus, 1874).

Diphyes subtilis, Chun, 1886, p. 449 ; 1897 4, p. 103 ; Lens & Van Riemsdijk, 1908, p. 47.

Monophyes diptera, Haeckel, 1888, p. 129.

Diphyes elongata, K. C. Schneider, 1898, p. 85 (non Hyndman, 1841, p. 165).

Occurrences : 25 to 0 fathoms; 3lq@. 1 anterior nectophore.

75 to 0 fathoms; 329. 1 anterior nectophore.

100 to 0 fathoms ; 24 d, 32d, 32 p, 35 6, 366. 17 anterior nectophores ;

all about 5 mm. long.

344 MR. HENRY B. BIGELOW—BISCAYAN PLANKTON:

The earliest name, elongata, cannot be used, since it was preoccupied by Hyndman

for another Diphyes.

This species, thanks to the peculiar form of its somatocyst, with long thread-like stalk

and spherical terminal dilatation, is one of the most easily recognized members of the

genus. Lens and Van Riemsdijk (1908) found that the form of this organ and

the rounded apex of the anterior nectophore were constant in a large series from Naples,

and the 18 specimens from the Bay of Biscay are perfectly typical so far as both

characters are concerned. To Chun’s accounts I need only add that, in spite of a

shallowness of the hydrcecium, so extreme that we may almost speak of its cavity as

entirely suppressed, its dorsal wall below the level of the opening of the nectosae is

divided so as to form a right and left wing, muchas in D. fowleri and in Muggiea kochit.

This region is not clearly shown in Chun’s figure. All of the specimens were more or

less distorted ; in most of them the subumbrellar musculature is destroyed and the

entire stem with its appendages torn off. No inferior nectophores could be identified,

nor could I find any of its eudoxids.

Diphyes subtilis is one of the most common Siphonophores in the Mediterranean, where

it is an epiplanktonic form of regular occurrence. So far as I am aware, it has been

recorded in the Atlantic only from the Canary Islands, where Chun (1388) found

it only occasionally. It is not present in the extensive West Indian collections which I

have examined. The present captures, all in open nets, are too few to warrant specula-

tion as to its bathymetric range further than to note, as rather surprising in view of its

previously known habitat, its absence from all the surface hauls. They show, however,

that it is not so exclusively a subtropical form as has been supposed, for it was taken

in temperatures somewhere between 52° (100 fathoms) and 66° F. (surface).

DIPHYES APPENDICULATA, Eschscholtz.

Diphyes appendiculata, Eschscholtz, 1829, p. 138, Taf. 12. fig. 7; Huxley, 1858, p. 34, pl. 1. fig. 2;

K. C. Schneider, 1898, p. 85.

Diphyes bipartita, Costa, 1836, ‘ Genere Diphya,” p. 4, Tav. 4; Chun, 1897 4, p. 24.

Diphyes elongata, Hyndman, 1841, p. 165, figs. 1-4.

Diphyes acuminata, Leuckart, 1853, p. 61, Taf. 3. figs. 11-20.

Diphyes sieboldii, Kélliker, 1853 a, p. 36, Tab. 11. figs. 1-8.

Diphyes gracilis, Gegenbaur, 1854 a, p. 309, Taf. 16. figs. 5-7.

? Diphyes pusilla, McCrady, 1857, p. 174.

Tn this list only the more important references are given.

I follow Huxley and K. C. Schneider in uniting in one species the Atlantic D. bipartita

and the Pacific D. appendiculata, because my examination of large series from both, as

well as from the Indian Ocean (Bigelow, 1904), has failed to reveal a single character to

separate them.

This species and its eudoxid are so well known that I need only mention here that

the collection shows that the presence of only three ridges at the apex of the anterior

nectophore is constant, and that the fourth ridge, which arises some distance below the

apex, invariably becomes the left lateral.

THE SIPHONOPHORA, 345

D. appendiculata is the most abundant siphonophore in the collection. Its occur-

rences were as follows :—

Depth in Number of Anterior Posterior Budoxid

fathoms. hauls. Nectophores. | Nectophores. ;

0 15 9 5 257

25 5 34 7 22

50 9 38 18 57

75 6 13 7 24

100 10 96 55 89

200-100 4 8 8

300-200 1 1

500-400 il 3 4 5

500-250 1 3

205 104 454

Fortunately the anterior and posterior nectophores are all in such good condition as

to be recognized readily. But many of the eudoxids are very much battered. Only

those which could be identified certainly are listed above; there are a considerable

number in addition which may belong to this same species.

D. appendiculata has long been known to be a widely distributed form, not only

belonging to the epiplankton, but living at very considerable depths (1300 metres, Chun,

1887; 1000 metres, Bedot, 1904). Indeed, it is perhaps the most nearly universal

of all siphonophores. The captures show that its eudoxid is commonest on the surface,

but that in the Bay of Biscay the polygastric generation, on the contrary, is most

abundant in the zone between 100 and 25 fathoms. The scarcity of the adult on the

surface is surprising, in view of the fact that it has been so commonly taken there in

other localities, both tropical and temperate. Below 100 fathoms both adult and

eudoxid are rare; but the excellent condition of the specimens of both forms, which were

taken in the closing-net between 500 and 400 fathoms, indicates that they were alive at

that depth, and not merely corpses on their way to the bottom.

Its vertical range in the region now under consideration parallels that of Aglantha

among the Medusz (Browne, 1906, p. 174), a genus most common between 100 and

50 fathoms, though occurring in lesser numbers at much greater depths.

D. appendiculata, like Nausithoe punctata among Scyphomedusz, passes through a

wide range of temperature in its distribution, hoth vertical and horizontal. The evidence

of the present collection would suggest, for the polygastric generation, an optimum of

50°-60° F. But it occurs commonly on the surface in the tropical regions of all three

great oceans, in temperatures of from 70°-78°. The most northerly record which can

SECOND SERIES.—ZOOLOGY, VOL. X. 55

346 MR. HENRY B. BLGELOW—BISCAYAN PLANKTON:

safely be attributed to this species is that by the Plankton Expedition (Chun, 1897 0) of

an eudoxid in the closing-net, 800-1000 metres, 60° 2’ N., 22°'7' W., at a temperature of

42°8° F. (11:°6°C.). Romer (1902, p. 176), it is true, records anterior nectophores from

Spitzbergen. But since he says that these specimens had “ Zahnartigen Vorsprénge an

den untere Schirmrande,” i.e. basal teeth, they cannot have belonged to D. appendiculata.

On the surface the polygastric state of this species is known from as far north as the

northern coast of Ireland.

DIPHYES FOWLERI, sp. nov. (PI. 28, fig. 5.)

Occurrences: Surface. 21 e. 4 anterior nectophores.

50 to 0 fathoms. 386d, 26c. 4 5 fe

75 to 0 fathoms. 33h. i

39 be)

100 to 0 fathoms. 21h, 246, 24d, 24e,309, 39 nH

80h, 32d, 350, 35 x, 360,

36 e.

250 to 0 fathoms. 36h. ill a eS

300 to 0 fathoms. 364%. 4A

29 39

The specimens all measured about 11 mm. in length.

I have likewise been able to study 6 anterior nectophores of this species from the

West Indies, and it is represented in the ‘ Albatross’ Eastern Pacific collection by 8.

Comparison of Atlantic with Pacific specimens has revealed no differences sufficient to

justify their separation.

In its general form D. fowleri resembles the Diphyes subtiloides of Lens and Van

Riemsdijk (1908) so closely that only a slight difference in the structure of the

hydreecium and the shape of the somatocyst distinguish it from the latter.

Anterior Nectophore-—The diagnostic characters are as follows: there are constantly

five ridges at the apex, and these, which are not prominent, run to the base without

branching. In the best-preserved specimens the general form is high and narrow, but

the more battered individuals are often proportionately much broader. This difference

is probably to be correlated with contraction or expansion of the nectosac. There are —

no baso-lateral teeth, and the dorsal tooth is represented merely by a slight prominence

of the dorso-basal angle. The nectosac reaches almost to the apex, and the canals

follow the usual course.

The hydreecium is an important character, since it serves to distinguish D. fowleri

from most other diphyids. It is very short, and lies wholly below the level of the

mouth of the nectosac, and is broadly conical. Its form will be more readily understood

from the accompanying figure than from a verbal description. In D. subtiloides,

although the hydrcecium is of similar outline and position according to the figures of

Lens and Van Riemsdijk (1908, pl. 7), the dorsal hydreecial wall below the bell-opening

is entire, though slightly concave. But in D. fowleri, both from the Atlantic and from

the Pacific, the wall is divided as in many diphyids, the division being to one side of the

mid-line. In most instances the left-hand flap is the larger, but several of the

specimens are too much distorted to show whether or not this is invariably the case.

THE SIPHONOPHORA. 347

The somatocyst is spherical or pear-shaped, and, instead of lying nearly in the longi-

tudinal axis of the nectophore, is transverse, a form and position constant in the entire

series of 73 specimens, whether Biscayan, West Indian, or Pacific. In D. subtiloides

the somatocyst, though short, is of the usual fusiform type, merely somewhat narrower

near the base, and Lens and Van Riemsdijk found no noticeable variation from this

type in 110 specimens.

Stem and Appendages,—The pedicular canal of the nectosac runs almost directly down-

wards throughout its short course to the apex of the hydrecium. In only one specimen

was an entire group of developed appendages still attached. This consisted of bract,

siphon, tentacle, and gonophore. Although the latter was sufficiently developed for

identification, there was no trace of any special nectophore, and it is on this evidence

that the species is referred to Diphyes rather than to Diphyopsis.

Inferior Nectophore.—None of the specimens had the second nectophore still attached,

but in most of them the remnants of what was apparently the pedicular canal could be

detected at the base of the stem, and it is on the strength of these that the species is

referred to the Diphyide. There are several inferior nectophores in the collection so

crumpled and distorted as to be past description or identification. It is possible that

some or all of them may belong to D. fowler?.

The depths of capture listed above show that, though this form occurs at the surface,

it is most abundant between 50 and 100 fathoms, 7. e. in a temperature of about 52° F.

It seemed to me so unlikely that a North Atlantic species with this habitat, so easily

recognized as the present, and so common as it appears to be, should,so long have

escaped notice, that 1 was loth to make it the basis for a new specific name. But

examination of the literature of both Diphyids and Monophyids seems to leave no other

course open.

From the Atlantic forms with baso-lateral teeth—for example, Diphyopsis dispar,

Cham. & Eys.; Diphyes steenstrupii, Gegenbaur; D. serrata, Chun; and Doromasia

picta, Chun,—and from the various Pacific species with this same character, to be

discussed in my Report on the ‘ Albatross’ Siphonophores, it is readily distinguished by

the entire lack of such structures. The Atlantic Diphyopsine previously known, which

agree with Diphyes acuta in this respect, are D. appendiculata, Eschsch. (=seeboldii,

Gegenbaur, = bipartita, Costa); D. arctica, Chun; D. subtilis, Chun; and Diphyopsis

hispaniana, Mayer. But from all these, as well as from Diphyopsis mitra, Huxley

(=D. diphyoides, Lens and Van Riemsdijk), and Diphyes chamissonis, Huxley, as yet

recorded only from the Indo-Pacific region, it is separated by the shortness and position

of the hydrecium, and by the structure of the somatocyst, both of which characters

have proved constant. Similarly, in addition to the apparent presence of an inferior

nectophore, it is separated from the monophyids Muggiva kochii, Will, and W. atlantica,

Cunningham.

_Among Galeolarine, the only species which might perhaps agree with it with regard

to the somatocyst is Galeolaria turgida, Gegenbaur. But in the latter the structure of

the hydreecium, and particularly the two long dorsal hydrecial wings, are entirely

different from the condition in D. acuta. From G. truncata, Sars, which somewhat

55*

348 MR. HENRY B. BIGELOW—BISCAYAN PLANKTON:

resembles it in the absence of “wings” and in general appearance, it is separated

by the structure of the somatocyst, which, in the latter, is of the ordinary fusiform type

and of considerable length. The only species with which it might be confused is Diphyes

subtiloides, Lens and Van Riemsdijk ; but, as noted above, it is easily distinguished from

that form by its peculiar somatocyst.

CuunteHyes, Lens and Van Riemsdijk, 1908.

CHUNIPHYES MULTIDENTATA, Lens and Van Riemsdijk.

Chuniphyes multidentata, Lens and Van Riemsdijk, 1908, p. 13, pl. 1. figs. 9-11, pl. 2. figs. 12-15.

This very interesting species is represented by 7 anterior and 8 posterior nectophores.

The records of its occurrence are :

250 to 0 fathoms. 36h. 1 anterior and 1 posterior nectophore.

300 to 0 fathoms. 36%, 1 anterior nectophore.

1250 to 0 fathoms. 27a. 1 anterior and 1 posterior nectophore.

1500 to 750 fathoms. 30a. 1 anterior and 2 posterior nectophores.

1250 to 1000 fathoms. 2706. 1 posterior nectophore.

2000 to 1000 fathoms. 30e. 3 anterior and 3 posterior nectophores.

The ‘Siboga’ specimens (1 anterior and 1 posterior nectophore) from which Chuniphyes

was originally described were so much distorted as to make its general structure seem

more unusual than it actually is. In point of fact, it differs in no essential feature from

other Diphyids, although the unusual number and arrangement of the ridges and the

peculiar form of the hydreecium and somatocyst justify the retention of Chuniphyes as a

distinct genus. The pyramidal shape of the nectophores and the form of the hydreecium

strongly suggest that its affinities are with the Diphyopsine rather than the Galeolarine.

Unfortunately, however, neither the ‘ Siboga,’ the ‘ Albatross,’ nor the present specimens

afford any information as to the structure of the groups of appendages, and until we

know whether they are set free as eudoxids, or remain permanently attached to the

stem, it is impossible to settle this point definitely.

Comparison, side by side, between the Biscayan and the ‘ Albatross’ ‘Eastern-Pacific

specimens of Chuniphyes fails to show any differences sufficient to separate them into

two distinct species. And inasmuch as both these series agree with Lens and Van

Riemsdijk’s description of the ‘ Siboga’ material, so far as the poor condition of the latter

allows one to judge, all must be referred to the one species, C. multidentata. This form

is described and figured in detail in my report on the ‘ Albatross’ Siphonophores, but to

make its identification easy, the more diagnostic characters may be repeated here.

The anterior nectophore of C. multidentata may be distinguished at first glance by its

pyramidal form, by its prominent ridges, and by the peculiar form of its obliquely

truncate base. At the sharp-pointed apex there are four ridges: 1 dorsal, 1 ventral, and

a lateral on each side. A short distance below the apex the dorsal and the two laterals

each branch dichotomously, so that there are seven at the base.

The facets are a triangular dorsal, enclosed by the two branches of the dorsal

ridge, and on either side three laterals; the dorso-lateral and the median-lateral being

THE SIPHONOPHORA. 349

triangular, the ventro-lateral irregular in outline. Of these, only dorso- and ventro- laterals

extend to the apex. The ventral ridge does not branch, and there is no true ventral

facet, although Lens and Van Riemsdijk speak of the hydreecium as such. Each ridge,

except the ventral, terminates in a pronounced tooth, and there is in addition a tooth

breaking the basal outline of the median lateral facet.

The nectosac extends upward slightly beyond the mid-level of the nectophore, and

is rounded apically. In the Biscayan material it is somewhat longer than in the

Pacific specimens. But in view of the possibilities of distortion through contraction,

and of the fact that all of the specimens are more or less battered, such a slight difference

does not justify specific separation. The course of the subumbrellar canals is of the

usual type.

The hydrecium reaches to about the same level as the nectosac, not to the apex as

described by Lens and Van Riemsdijk. Along its ventral face it is open for its whole

length, and its deepest point is opposite the mid-level of the nectosac.

The somatocyst is of peculiar form, in that shortly above its point of origin it becomes

much dilated and then contracts once more to run as a narrow tube nearly to the apex.

In the form of this dilatation there is a slight difference between Biscayan and Pacific

specimens. In the only one of the latter in which it is intact it is spherical. In four

of the Biscayan specimens it projects on either side in a short transverse horn. In one

Atlantic specimen, however, the horns are so much smaller as to suggest a transition to

the condition in the Pacific material ; therefore I consider this divergence of no more

importance than the slight difference in the form of the nectosac in the two collections.

The identification of the inferior nectophores listed above, all of which were detached,

is made certain by their close resemblance to the corresponding nectophores of two

entire colonies in the ‘Albatross’ collection. heir general form, especially the open

hydreecium, covered only near the apex by two short flaps, the six prominent ridges

(only four at apex), and the asymmetry of the basal teeth, of which the right ventral is

much the largest, still serve for identification. In both nectophores the unusual

prominence and brownish colour of the ridges, already noted by Lens and Van Riemsdijk

and very noticeable in the ‘ Albatross’ specimens, form good external field marks for

this species.

Chuniphyes has never been taken on the surface; the ‘ Albatross’ records are both

from 300-0 fathoms.

The present captures show a range, at the least, from 1000-250 fathoms. Especially

instructive are the closing-net records of 1250-1000, 2000-1000, and 1500-750 fathoms,

since, of course, they show that the material actually came from these zones. How near

this.species may have come to the surface cannot, of course, be absolutely determined.

But its absence from all hauls from depths of less than 250 fathoms suggests that the

latter level is near the upper limit of its distribution. The number of specimens taken

is far too small to justify any conclusion as to its relative abundance at different

depths.

350 MR. HENRY B. BIGELOW—BISCAYAN PLANKTON:

POLYPHYIDA, Chun, 1882.

Hipropopius, Quoy et Gaimard, 1827.

Hriproropivus urprorvs (Forskal), Schneider.

Gleba hippopus, Forskal, 1776, p. 14, Taf. 43. fig. E.

Gleba excisa, Otto, 1823, p. 309, Taf. 42. fig. 3 a—-d.

Hippopodius luteus, Quoy et Gaimard, 1827, p. 172, pl. 4a. figs. 1-12; Chun, 1897 4, p. 34.

Hippopodius mediterraneus, Costa, 1836, “ genere ippopodio,” p. 3, Tav. 2.

Hippopodius neapolitanus, Kolliker, 1853 a, p. 28, Taf. 6. figs. 1-5.

Hippopodius gleba, Leuckart, 1854, p. 299, Taf. 12. figs. 1-5.

Hippopodius hippopus, K. C. Schneider, 1898, p. 82.

In this list only the more important references are given. For a more extended

bibliography, see Chun (1897 0, p. 34).

I am quite willing to admit that, as has often been pointed out, Forskal’s two figures,

on which his name Gleba hippopus is based, are so lacking in detail that it is impossible

to reach any altogether satisfactory identification of them. But the probability that

they belong to the well-known form so often described as Hippopodius luteus is so

strong that J believe K. C. Schneider was justified in substituting the name hippopus

for luteus, as a doubtful synonym of which it is listed by Chun (1897 4). To do so will

no doubt add stability to the nomenclature of the genus, for until hippopus is connected

with some actual species it will continue to be a source of confusion. Even if hippopus

be not adopted, luteus, used both by Chun (1897 6) and by Lens and Van Riemsdijk

(1908), cannot be employed, because both these authors list as a synonym Otto’s name

excisa, which autedates luteus.

Occurrence: 300 to 0 fathoms. 36%. 6 loose nectophores.

It is surprising that the definitive nectophores of this species so common in the

Mediterranean and so often recorded from the warmer parts of the Atlantic, as far

north as the British coast (Chun, 1897 6), should have been taken only in one haul.

The material, moreover, was in very poor condition. In addition to these definitive

nectophores, the spherical primary nectophores, so well described by Chun (1897 a),

were taken as follows :—

75 to 0 fathoms. 34c. 7 specimens.

100 to 0 fathoms. 35f 1

200 to 0 fathoms. 369. 2

300 to 0 fathoms. 36k. 5 5

150 to 50 fathoms. 21p. 1

250 to 150 fathoms. 3835p. 1 a

They are all at the stage at which the bud for the first definitive nectophore is first

visible (Chun, 1897 a, fig. 6 a), and in each the stem bears a single large terminal siphon,

with tentacle, and one or two small buds for future siphons. In their spherical form,

shallow nectosac, and deep and narrow hydreecial furrow, they agree very well with

Chun’s figure; but while he records 7 mm. as the greatest diameter, one of the present

series has attained the remarkable size of 10 mm. It is interesting to observe that this

’ THE SIPHONOPHORA. 351

species was not taken in any of the surface hauls. Chun (1887) has already recorded

the adult from various depths from the surface to 1200 metres. And according to his

observations the larval “ primary ” nectophores apparently occur on the surface only rarely.

But the fact that in the Bay of Biscay they were most numerous between 75 fathoms

and the surface shows that there, at least, they were members of the epiplankton.

Nor do any of the present records demonstrate its occurrence much below 150 fathoms,

between which depth and 250 fathoms a single example was taken in the closing-net.

Voerta, Kolliker, 1853.

VoeTia PENTACANTHA, Kdlliker. .

Vogtia pentacantha, Kolliker, 1853, p. 31, Tab. 8; Keferstein und Ehiers, 1861, p. 23, Taf. 5.

figs. 12-15; Chun, 1897 4, p. 35, Taf. 1. figs. 11-14.

Hippopodius pentacanthus, Claus, 1863, p. 551, Taf. 47. figs. 23-25; K. C. Schneider, 1898, p. 84.

Occurrence: 350 to 0 fathoms. 367. A colony with 6 nectophores, but with only

the basal remnants of the stem intact.

The chief difference between this species and V. spinosa, Keferstein and Ehlers

(=V. kéllikeri, Haeckel), is that in the former the spine-like gelatinous processes

characteristic of the genus are restricted to the angles or ridges of the nectophores,

whereas in the latter they occur closely crowded over the flat lateral surfaces as well.

The evidence afforded by the specimens recorded by Chun from the Plankton expedition,

and especially actual comparison between the present example and the large series of

typical spinosa in the ‘ Albatross’ Eastern Pacific collection, and with the few necto-

phores described below as probably belonging to that species, points to the validity

of this difference as a specific distinction. Furthermore, the shape of the older

nectophores in the two species is dfferent, those of spinosa being flatter and more regular

than they are in pentacantha. We must, however, admit that to determine the con-

stancy of these characters will require the examination of a considerable series of

V. pentacantha. And until this is done, the question whether pentacantha and spinosa

are distinct, or merely represent two phases of one species, must remain without a final

answer. The attachment-of the nectophores in two alternating rows follows the same

plan as in the better-known genus Hippopodius, with which the Vogtia was confused by

Gegenbaur (1860) and Claus (1863). Unfortunately, only the basal end of the stem,

with a very few small buds, is still intact. Therefore no description of the appendages is

possible.

? Voertra spinosa, Keferstein and Ehlers.

Vogtia spinosa, Keferstein und Ehlers, 1861, p. 24, pl. 5. fig. 16 ; Chun, 1897 4, p. 103.

Vogtia kéllikeri, Haeckel, 1888, p. 182, pl. 29. figs. 9-14.

Occurrences: 200 to 0 fathoms. 36g. 4 detached nectophores.

250 to 150 fathoms. 35p. 8 ” BS

These nectophores are all somewhat distorted, and several of them badly flattened and

torn. All of them, however, show more or less clearly the spinous processes on the flat

~~, @e 4

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LISRARY

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AB?

352 MR. HENRY B. BIGELOW—BISCAYAN PLANKTON:

marginal surfaces characteristic of V. spinosa and well figured by Haeckel (1888). The

similarity between them and the Pacific series of spinosa is a further reason for identi-

fying them provisionally as that species. V. spinosa has been previously recorded only

from off the coast of Brazil (Keferstein and Ehlers) and from the South Atlantic (37° 3'S.,

44° 17' W., Haeckel).

RHIZOPHYSALIZ.

A single fragmentary rhizophysid was taken at Station 24/", surface ; probably on the

wire. But unfortunately it consisted only of three fragments of the stem, without any of

the appendages, and therefore cannot be identified, even generically. |

BATHYMETRIC DISTRIBUTION.

The number of specimens of each species sent to me from each of the various horizons

is given in the accompanying table [in the case of the diphyids only the anterior

nectophores are included, to prevent duplication].

| 2000—1000.

| 2000—1500.

A é

is! [3] |e] Is] Ieisisisis} |Slel8

SiS] oso] co [slSlSi[olslolBlalals/B/A/S/SiSis/Sizia

Depth in fathoms ........ S ob é a g |glalsisieldisig/aieisisieieisisisisis

Nectopyramis thetis............ iL

MiG GUA ICOCKat mie volnciesien eee ee Wee LO cll) aL Bale eae

Rosdced pucata 2... 00... ees we | ome al licteus nel geyetall exey tuna ted ees eel eI ated (Rene (22/1 suc fest evel peg ened [Le

Diphyes subtilis .............. oe IE loc ih |p hee

3 G@ppendiculata ........ DS SB | WS OG ee alee eee tere farelliors| fl lisse ||. ile) ted

_ < ree ol Sales yA PER ay AOE SEN leoliae|la alle ollo olloa\|aalloalloaleralienal|orol |)

3) fowlert ne Ree nsieitee « AN ee CN rial es) eal elle ol Jel Sells alle ol he’

Chuniphyes multidentata ...... en eee eee ee mies tallealts, liosll Jule globe Mee emails eaeelis IE TL Sky. |S

Hippopodius hippopus ........ oe say aan ceel||.ae8 loolloal|é-a|to alle ofjocllsalfal

A et _pllarvaremerets 9c cead| ested |e? 16 We oa ool) 2) ho-a)/o5]] A

Vogtia pentacantha .......... en eras eae een Marre |aelaole=|loa}o olloallacile

351) SPUROSG ay. cewek oer Fans eae eal Mee Ween sali citooll Ll. oiloclp Zt

Rhizophysid fragment ........ 1

(NOTE.—The smaller Calycophore are very delicate ; they were peculiarly often caught

up in clots of plankton, caused by the branching spines of Phzodarian Radiolaria or

by silk threads from the tow-net, from which they could only be released—if at all—in

THE SIPHONOPHORA. 353

a hopelessly tattered state. It was therefore impossible satisfactorily to sort out, from

the material captured, anything like the total number of specimens present. Conse-

quently the number of specimens from any haul, sent to Mr. Bigelow, can only be

taken to indicate the comparative abundance or scarcity of a species in the very roughest

and most general way. Some deductions as to their distribution may, nevertheless,

fairly be drawn from the number of hauls in which they occurred. For reasons given

in earlier papers of this series, we must omit, as unfair for comparison with ordinary nets,

the nine hauls made at the surface with silk of 180 meshes per linear inch ; there remain

16 hauls at this horizon for comparison; for other reasons 35c¢ (75 fathoms) and 35d

(100 fathoms) are also omitted. Otherwise the numbers of hauls shown on the general

table (p. 858) remain good, since there seems no reason to omit the hauls with a silk at

18 meshes per inch, in the case of these comparatively large forms.—G. H. F.)

The only species taken with sufficient regularity to allow its vertical distribution to be

worked out in any detail is Diphyes appendiculata and its eudoxid.

The polygastric stage occurred between the surface and 200 fathoms

At 0 fathoms in 18 per cent. of the total number of comparable hauls.

25 Orne 25 te - ” »

50—0 5 38 rf 99 » »

75-0 3», = 50 és He by -

100—0 Ag 42 o “ - 9

Between 200 and 100 fathoms in 57 per cent. of the total number of comparable hauls.

Below 200 fathoms it was taken in the only closing trawl made between 500 and 250,

and in one each of the three closing-nets hauled from 300 to 200 and from 500 to 400

fathoms. It did not occur in any open net from a depth greater than 100

fathoms.

This table shows very clearly that D. appendiculata was not common on the surface,

and the preceding one, actual numbers of specimens sorted out, emphasizes this fact

even more strongly. On the other hand, it is obviously very rare below 200 fathoms,

its only record from below that depth being in the three closing-nets, between 200 and

500 fathoms. The tables suggest that it was most abundant between 75 and 100

fathoms. It is true that the largest number of captures in proportion to hauls is from

200-100 fathoms; but since the total number of hauls at that zone was only seven, and

the total number of specimens small, it is not so safe to draw inferences from them as

from the 100-fathom hauls, of which there were over three times as many. But the

excellent condition of the specimens taken at 200-100 fathoms shows that they were

actually living at that depth.

That the polygastric stage of D. appendiculata occurred in none of the eight open-net

hauls from below 100 fathoms is rather remarkable, since in their passage upward the

nets must, of course, have passed through the zone where the species was most plentiful.

As pointed out above (p. 345) the sporadic occurrence of this form in the closing-

net at considerable depth is not surprising in view of the previous records of its

capture.

SECOND SERIES.— ZOOLOGY, VOL. X. 56

304 MR. HENRY B. BIGELOW—BISCAYAN PLANKTON:

The endoxid of D. appendiculata was taken

At 0 fathoms in 68 per cent. of the total number of comparable hauls.

25—0 ¥ 16 5s 5s 9 »

50—0 ye 23 95 + Pr 9

75—0 “p 20 i a x &

100—O 53 14 : 5 ” 9

and in one haul only at all depths below 100 fathoms.

The eudoxid, then, as already noted, is evidently most abundant at or near the surface,

and there is nothing to show that the captures in open nets hauled from 25, 50, 75, or 100

fathoms did not come from near the surface, while the net was on its way upward *.

The sporadic occurrence of this form at 400-500 fathoms (one closing-net, five specimens)

was unexpected. The material is in excellent condition, with well-developed sexual

products, and the fact that it was taken in the same haul with three excellent specimens

of the polygastric generation suggests that the species was not only alive, but repro-

ducing itself at that depth.

In general, the table of captures shows a great poverty of Siphonophores at the surface

in the region studied, the only records from that zone being Diphyes appendiculata and

its eudoxid, four specimens of D. fowlerz, and a Rhizophysid fragment.

The greatest abundance of Wuggiea kochii, Diphyes subtilis, D. appendiculata (Poly-

gastric), and D. fowleri was evidently between 100 fathoms and 25 fathoms. Though

Rosacea plicata was taken only below 200 fathoms, it has previously been recorded from

the surface, and I have studied specimens from the Pacific taken at the surface.

Chuniphyes multidentata, on the other hand, has so far been recorded only from con-

siderable depths (p. 849), and is in all probability a typical representative of the

permanent Mesoplankton or Intermediate fauna.

* [I have dealt with this point elsewhere. In cases where the matter can be checked statistically, it is apparent

that, down to something like 100 fathoms, the contamination of the sample obtained by hauling horizontally at

(say) 50 fathoms for half an hour through something like half a mile of water, by the fauna of the comparatively

insignificant distance of the vertical haul to the surface, is negligible—G. H. F.]

THE SIPHONOPHORA. 35

BIBLIOGRAPHY.

In the following list only the papers quoted in the foregoing pages are included.

For a more extensive bibliography of the Siphonophores see Lens and Van Riemsdijk,

1908, and my forthcoming report on the ‘ Albatross’ collection.

Bepor, Mavricez, 1882.—“ Sur la faune des Siphonophores du Golfe de Naples.” Mitth. Zool. Stat.

Neap. vol. iii. pp. 121-123.

—, 1896.—“ Les Siphonophores de la Baie d’Amboine.” Revue Suisse Zool. t. iii. pp. 367-414,

pl. 12.

— , 1904.—“‘ Siphonophores provenant des Campagnes du Yacht ‘ Princesse-Alice’ (1892-1902).”

Résultats Camp. Scient. par Albert I., Prince Souverain de Monaco, fase. xxvii. 27 pp., 4 pls.

BiceLtow, Henry B., 1904.—‘‘ Medusz from the Maldive Islands.” Bull. Mus. Comp. Zoél., Harvard

vol. xxxix. no. 9, pp. 245-269, 8 pls.

Buarnvitte, Henrt Marie Ducroray pz, 1834,—Manuel d’Actinologie ou de Zoophytologie. Paris,

8 and 644 pp., Atlas of 99 pls.

Browne, E. T., 1906.—* The Meduse.” Biscayan Plankton: Part IX. Trans. Linn. Soc. ser. 2, vol. x.

part 6, pp. 163-180, pl. 13.

Buscu, Witueitm, 1851.—Beobachtungen tiber Anatomie und LEntwickelung einiger Wirbellosen

Seethiere. Berlin, 143 pp., 17 Taf.

Cuamisso, ApaLBert pe, et Eysennarpt, C. G., 1821.—~‘ De Animalibus quibusdam e Classe

Vermium Linneana etc., Fasc. 2.’ Nova Acta Acad. Ces. Leop. vol. x. pp. 343-374,

pls. 24-33.

Cuun, Cart, 1882.—“ Ueber die cyklische Entwickelung und die Wirwandtschaftsverhiltnisse der

Siphonophoren.” Sitz. k. pr. Akad. Wiss. Berlin, lii. 1882, pp. 677-694 [1155-1172],

Taf. 16.

——., 1885.—“ Ueber die cyklische Entwicklung der Siphonophoren.—2.” Sitz. k. pr. Akad.

Wiss. Berlin, xxvi. 1885, pp. 264-280 [511-528], Taf. 2.

——, 1886.— Ueber Bau und Entwicklung der Siphonophoren.—3.” Sitz. k. pr. Akad. Wiss.

Berlin, xxxv. 1886, pp. 449-456 [681--688].

—,, 1887.—“ Die pelagische Thierwelt in grésseren Meerestiefen und ihre Beziehungen zur

Oberflachenfauna.” Bib. Zool. Bd. i. 66 pp., 5 Taf.

——, 1888.—‘‘ Bericht iiber eine nach den Canarischen Inseln im Winter 1887-88 ausgefiihrte Reise.”

Sitz. k. pr. Akad. Wiss. Berlin, xliv. 1888, pp. 1-33 [1141-1173].

——, 1891.—* Die Canarischen Siphonophoren in monographischen Dargestellungen.—l. Stephano-

phyes superba.” Abh. Senckenb. naturf. Ges. vol. xvi. Heft 3, 74 pp., 7 Taf.

—, 1892.—‘‘ Die Canarischen Siphonophoren.—2. Die Monophyiden.” Abh. Senckenb. naturf-

Ges. Bd. xvii. pp. 57-144, Taf. 8-12 [6-10].

/——, 1897 a.—‘“ Ueber den Bau und die morphologische Auffassung der Siphonophoren.” Verh.

Deutsch. Zool. Ges. Leipzig, Jahresver. 7, pp. 48-111.

——, 1897 b.—“ Die Siphonophoren der Plankton-Expedition.” Ergeb. der Plankton Ex., Bd. ii.

K. b. 126 pp., 8 pls.

Cuaus, Cart, 1863.—“ Neue Beobachtungen iiber die Struktur und Entwicklung der Siphonophoren.”

Zeit. wiss. Zool. Bd. xii. pp. 536-563, Taf. 46-48.

—, 1874.—“ Die Gattung Monophyes, und ihr Abkémmling Diplophysa.’”’ Schriften Zool. Inh.

Heft i. part 2, pp. 27-33, Taf. 4.

_. Costa, O. G., 1836.—Fauna del Regno di Napoli &c. Medusari, pp. 1-20, 1-18, 1-14, 1-10, 1-12,

8 pls. (H. mediterraneus, Costa, p. 3, pl. 2 [6].)

(LIBRARY |=

VZ > a

SO, haas®

ore

356 MR. HENRY B. BIGELOW—BISCAYAN PLANKTON :

Cunnineuam, J. T., 1892.—“ On a Species of Siphonophore observed at Plymouth.” Journ. Marine

Biol. Assoc. Plymouth, n. s. vol. 11. pp. 212-215.

Cuvirr, G., 1817.—Le Régne Animal &e. Paris, 4 vols., 15 pls.

Dette Curase, S., 1842.—Descrizione e Notomia degli animali invertebrati della Sicilia Citeriore.

Naples, tom v. & atlas.

Escuscnoutz, J. F., 1829.—System der Acalephen. Berlin, 6+190 pp., 16 Taf.

Forskat, P., 1776.—Icones rerum naturalium quas in itinere orientali depingi curavit Petrus Forskal. ..

edidit Carstem Niebuhr. Hauniz, 15 pp., 43 pls.

Fowrsr, G. H., 1904.— Biscayan Plankton. 1. Methods and Data.” Trans. Linn. Soe. ser. 2, Zool.

vol. x. pt. 1. pp. I-11.

GeeenBaurr, C., 1854 a.— Beitrige zur niiheren Kenntniss der Schwimmpolypen (Siphonophoren).”

Zeit. wiss. Zool. Bd. v. pp. 285-343, Taf. 16-18.

——, 1854. b.—“ Ueber Diphyes turgida nebst Bemerkungen tiber Calycophoriden.” Zeit. wiss. Zool.

Bd. v. pp. 442-454, Taf. 2, 3.

——, 1860.—“ Neue Beitrage zur naheren Kenntniss der Siphonophoren.” Nova Acta Acad. Ces.

Leop. vol. xxvii. 94 pp. Taf. 27-33.

Harcxet, E., 1888.—“ Siphonophore of the ‘Challenger.’” Rep. Sci. Results H.M.S. ‘ Challenger,’

Zoology, vol. xxviii. 380 pp., 50 pls.

Houxtey, T. H., 1858.—The Oceanic Hydrozoa &c. Ray Soc. London, 141 pp., 12 pls.

Hynpman, G. C., 1841.—‘ Note on the Occurrence of the Genus Diphya on the Coast of Ireland.”

Ann. Mag. Nat. Hist. ser. 1, vol. vii. pp. 164-166, 4 figs.

Kererstern, W., und Exnuurs, H., 1861.—Zoologische Beitrage gesammelt im Winter 1859-1860 in

Neapel und Messina—I. Beobachtungen tiber die Siphonophoren ... Leipzig, pp. 1-34,

Taf. 1-5.

Koénuiker, A., 1853a.—Die Schwimmpolypen oder Siphonophoren yon Messina. Leipzig, 96 pp.,

12 Taf.

—., 1853 6.—“ Bericht tiber einige im Herbste 1852 in Messina angestelle vergleichend ana-

tomische Untersuchungen von Gegenbaur A. Kolliker und A. Miiller—A. Kolliker. Ueber

Siphonophoren.” Zeit. wiss. Zool. Bd. iv. pp. 306-315.

Lens, A. D., and Van Riemspisx, Tu., 1908.— The Siphonophora of the ‘Siboga’ Expedition.”

Siboga-Expeditie, Uitkom. op Zool..... Gebied, Livr. 38, 130 pp., 24 pls.

Lesson, R. P., 1843.—Histoire Naturelle des Zoophytes. Acaléphes. Paris, 8+596 pp., atlas of

12 pls.

Leucxart, R., 1853.—Die Siphonophoren. Giessen, 95 pp., 3 pls.

, 1854.—‘* Zur nihern Kenntniss der Siphonophoren yon Nizza.” Arch. f. Naturgesch. Jahrg. 20,

Bd. 1, pp. 249-377, Taf. 11-13.

McCrapy, J., 1857.—“ Gymnophthalmata of Charleston Harbor.” Proc. Elliott Soc. vol. i. pp. 103-

221, pls. vili—xu.

Mayer, A. G., 1900.—‘ Some Meduse from the Tortugas, Florida,” Bull. Mus. Comp. Zoél., Harvard

Coll. vol. xxxvii. no. 2, pp. 13-82, 44 pls.

Merscuntkorr, E., 1870.—“ Studies on Siphonophores and Meduse.” [Russian.] Bull. Friends Nat.

Hist. Moscow, pp. 225-370, 6 pls.

——., 1874.—“ Studien iiber die Entwickelung der Medusen und Siphonophoren.” Zeit. wiss. Zool.

Bd. xxiv. pp. 15-83, Taf. 2-12.

Orro, A. W., 1823.— Beschreibung einiger neuer Mollusken und Zoophyten.”’ Nova Acta Acad. Ces.

Leop.-Carol. Bd. xi. pt. 2, pp. 273-314, Taf. 38-42.

Quoy, J. R. C., et Garmarp, P., 1827.—‘ Observations faites 4 bord de PAstrolabe dans le détroit de

Gibraltar” Aun. Sci. Nat. t,x. pp. 1-21, 172-193, pls. 1, 2, 4-6. Also ‘Oken’s Isis,’ Bd. xxi.

THE SIPHONOPHORA. 357

Quoy, J. R. C., et Garmarpn, P., 1834.—‘ Voyage de découvertes de l’Astrolabe &ec..... de M. J.

Dumont D’Urville” Zoologie. Paris, tom. iv. 390 pp., Atlas Zool., tom. ii. Zoophytes, 26 pls.

Romer, F., 1902.—‘ Die Siphonophoren.’ Fauna Arctica, Bd. ii. part 4, pp. 169-184.

Sars, M., 1846.—Fauna littoralis Norwegie. Christiania, Heft i. 94 pp., 10 pls.

Scuyerper, K. C., 1898.—“ Mittheilungen tiber Siphonophoren.—3.” Zool. Anz. Bd, xxi. pp. 51-57,

73-95, 114-138, 153-173, 185-200.

Vanuorren, E., 1906.—‘ Siphonophoren.” Nordisches Plankton, Lief. v. Teil 11, pp. 10-39.

Voer, C., 1851 a.— Ueber die Siphonophoren.” Zeit. wiss. Zool. Bd. iii. pp. 522-525, Taf. 14.

, 1851 6.—Zoologische Briefe, &e. Frankfurt. Vol. i.

» 1854.—“ Recherches sur les Animaux inférieures de la Méditerranée.—1. Sur les Siphono-

phores de la Mer de Nice.” Mém. Inst. Nat. Genév. vol. i. pp. 1-164, 21 pls.

Witt, 1844.—Hore Tergestine .... Leipzig. iv & 86 pp., 2 pls.

EXPLANATION OF PLATE 28.

Reference letters.

Br. Bract. H. Hydrecium.

Cc’, C*, C*, C*. Bracteal canals. N.S. Nectosac.

C.D.R., C.D.L. Right and left dorsal somatic R', R’, BR. Bracteal ridges.

canals. R.D., R.V., R.L. Dorsal, ventral, and lateral

C.A. Ascending somatic canal. ridges.

C.H.R., CALL. Right and left hydreecial canals. SO. Somatocyst.

C.Ra. Radial canal of the nectosac.

Figs. 1-4. Nectopyramis thetis, sp. nov.

Fig. 1. Somewhat oblique lateral view. The heavy dotted line indicates the position of the basal portion

of the stem. From a slightly retouched photograph. x 6.

Fig. 2. Dorsal view. From a slightly retouched photograph. x 6.

Fig. 3. Bract, dorsal aspect. From a camera lucida drawing. x 35.

Fig. 4. Bract and gonophores. Slightly oblique lateral view. From a retouched photograph.

x about 35.

Fig. 5. Diphyes fowleri, sp. noy. Lateral view. Based on a camera lucida drawing. x about 10.

SECOND SERIES. —ZOOLOGY, VOL. X. 57

358

MR. HENRY B. BIGELOW—BISCAYAN PLANKTON. is

oY Pe a Sl es “Ss . ~ $

— & ss CS) fet = ‘S 8 aS = ‘S :

a “1 2 [O29 fs Ss >= SS] S&S 1S slses

Depth in ef] Sle lo S| 2 2S 1S 8 Depth in =| S| & | S/S [SSIS &

fatioms. Han. Ni s > £8 > S155, fathotte. Haul. Ni S| $ /8s g ne 5 =

2] 2 (CS ISS] OS [8 ESS) S/S 1S Ss Ls sss

S SES SS iS s S [cS pss) & |S Shs

Sis i/SA |As SFiS/AQAR AS

500—250 29 a + 100—0 24 e sp |) 2b

1500—750 30a 5a + 25 d

2000—1000 | 30e + 30 9 + +] 4+

‘Sika ek eka pearl ene 30h a5 etd teal eS

0 21e +] + 827 36 Var

212 + 382 n a

22 a + 32 p ate

229 33 d

23 6 + 346

23 d + 34d /.. eae

23 e + 35 b + +/+) +4

24 f 35d |.. -» | +

24g _ || lee) ee ga se |) 34 +

247 t+ 35 x Ae Bre oo |) atk

25 b +4 866 | + + ab

25h + 36 e ate ce +

On aie 150—0 36 f +

251 ak 150—50 21 p 4a aE

80¢ 150—100 Qn

33d ak 200—O 2la

25—0 26 a 86g | + ae +

80 8 200—100 216 an +

30 m 210

3la + 26 e ae

326 eet + 34h

82e + 35m ao

33 e + 35 2 ve

339 “+ 35 t

Bilin a8 250—0 36h | +} + Tleeh ieeta

849 367 Pepa pte

35 w 250—150 35 0

36¢ 35

50—O 91 g + 355 ii

25 e 300—0 36k + Soar |) ar || ae

Bs@ || <5 ay: 300—200 21e¢ a +

25k 26 f AF

26 ¢ +] + 35 1

30 d ale 350—0 36 7 +

80 7 400—300 2k

316 ate 32 7

2 a + 35 k

32h + 500—400 21 m

33 ¢ 35h

33 f ee t+ 35 7 a

36d at ius dt aur 750—500 22 6

75—O 30 Ff Ae fects 80%

329 + 34 e

82 m 44 48 b4 f

320 ae 1000—750 23 a

33 h ol + 27 e

34 ¢ RoW iWieen + 31d

35 a + 32 Ff

35e¢ Je 32k

35e af 1250—1000 | 24a

35 y 276 +

36a 3le

100—0 21h Be 1500—1250 | 25 f

217 307

22a 2000—1500 | 25 ¢

246 ok Be 26 b

24d ak #

* Note.—The first three hauls were made with the mesoplankton trawl.

Bigelow. : Trans Livw.Soc. Zoou.Ser.2 Vou.XPL.28.

Bigelow, del. et Photo. London Stereoscopic Co img

BIS CAYAN SIPHONOPHORA.

INDEX.

[Norr.—Synonyms and Native Names are printed in italics. A star is added to names which appear

Abyla leuckartii, Hualey, mentioned,

338.

Acanthephyra debilis, A. Milne-

Edw., 212; mentioned, 205, 207,

"214-217.

parva, Coutiére, mentioned, 206,

210, 211, 215.

purpurea, A, Milne-Edw., 206 ;

mentioned, 205, 207, 211,

212, 214, 2115-217.

var. multispina, Coutiére,

mentioned, 206,

Acanthoscina, Voss., 18.

acanthodes (Stebhing), 18.

serrata, Voss., 18,

Acanthosoma, Curt., larva of, 206,

Acera, Cuv., mentioned, 148.

Actzon, Oken, mentioned, 148.

AXjuorea forskalea, Péron et Lesweur,

mentioned, 166.

Aglantha digitalis, Haeck., men-

tioned, 176; distrib, of, 183, 184.

rosea, Browne, 175; distrib.,

182, 183, 186, 187;

tioned, 164, 176,

rosea, lorbes, 175; mentioned,

. 164, 165.

| sp., 176; distrib., 186, 187.

Aglaura, Péron et Lesueur, mentioned,

164, 165.

hemistoma, Péron et Lesueur,

176; distrib., 184, 186,187 ;

mentioned, 164,

Agliscra elata, Hacck., mentioned,

166.

Amalopenzus, S. 7, Smith, 206.

elegans, S. J, Smith, mentioned

205, 216, 217.

men-

SECOND SERIES,-—ZOOLOGY,

to be used for the first time. |

Amphipoda, distrib. of, 46-54.

Gammaridea, 14.

-—— Hyperiide, 17.

Amphipoda and Cladocera, with Notes

on the Larval Thyrostracan, by

Rey. T. KR. R. Stebbing, 13-54;

distribution of, by G. Fowler, 46-

54,

Anguillide, 197.

Anomura, 214,

Anomurous larve caught, mentioned,

205, 214, 216, 217.

Anthomeduse, 165, 170.

Apus, Schaef., history of, mentioned,

308.

Archeosecina *, Stebbing, 19; men-

tioned, 13, 22.

Bonnieri *, Stebbing, 19; men-

tioned, 13, 45, 50,

Archiconchecia cucullata, Brady,

mentioned, 220, 256, 272, 296.

Argyropelecus olfersi, Cuvier, men-

tioned, 193.

sp., 193, 203, 204.

Astacus crassicornis, Fubr., 24.

Atolla, ZZaeck., mentioned, 165.

Bairdii, Mewkes, 179; distrib.,

179, 185-187; mentioned,

166.

Balanus balanoides, Daywin, men-

tioned, 43.

Bathymetric Distribution, 352. ‘

Bentheuphausia amblyops, G. O. Sars,

mentioned, 107.

sp., 107; mentioned, 111, 117. |

VOL, X.

Biscayan Plankton, 1890, Methods

and Data, by G. H. Fowler, 1-11.

Bigelow, Henry B., Siphonophora,

337-358.

Bolitena, Bronn, mentioned, 160.

Bougainvillea autumnalis, Hartlaub,

170.

Brachyscelus, Spence Bate, 40.

Bovalii, Stebbing, mentioned, 41.

crustulum, Norman, 40; men-

tioned, 41.

globiceps, Claus, mentioned, 41.

mediterraneus, Claus, 40, 50;

mentioned, 13, 41.

sp., 41.

sp. indet., 50,

Brachyura, 214; larval, 215-217.

Browne,EdwardT,,Medusz, 163-181.

Brownia, Orb., mentioned, 138.

Byrne, L. W., Fishes of the Bay of

Biscay, 189-201.

Calearella, Souleyet, mentioned, 138.

Calycophoree, 338, 352.

Campanularia flexuosa, Hincks, 171 ;

mentioned, 165.

Campanulariide, 171.

Cancer crassicornis, Herbst, 24.

sedentartus, Forskal, 32.

Carangide, 200.

Caranx trachurus (Linn.), 200, 203,

204,

Carcinus mienas, Zinn., Records of,

280.

Caricyphus, Spence Bate, mentioned,

205, 216, 217; unknown larva

allied to, 213, 214.

360

Carinaria, Zam., mentioned, 151.

atlantica, Adams, mentioned,

145.

fragilis, Bory, mentioned, 145.

Gaudichaudi, MacDonald, men-

tioned, 145.

Grimaldii, Vayssiére, mentioned,

146.

Lamarcki, var. oceanica, Vays-

siére, mentioned, 146.

pseudorugosa, Vayssiére, men-

tioned, 146.

sp., 1438, fig. 152; distrib.,

156, 157.

Cayolinia inflexa, Zesueur, 149;

distrib., 155-157.

Cavoliniide, 148.

Cephalopoda of the Bay of Biscay,

by W. E. Hoyle, 159-162.

Ceratocymba, Chun, mentioned,

338.

Chetognatha, by G. H. Fowler, 55-

87.

Cheletropis,

138.

Cheenicosphera, Haeck., mentioned,

131.

Murrayana, Haeck., 132; men-

tioned, 133-135.

Chuniphyes, Lens §° van Riemsdijk,

348.

multidentata, Lens & van Riems-

dijk, 348: mentioned, 352,

354, 358.

Circe rosea, Forbes, 175.

Cirropteron, Sars, mentioned, 138,

Cladocera, 41.

Cladocera and Amphipoda, with

Notes on a Larval Thyrostracan,

by Rey. T. R. R. Stebbing, 13-45 ;

on their distrib., by G. Herbert

Fowler, 46-54.

Clio borealis, Bruguiére, mentioned,

ftnote 150.

caudata, MacDonald, mentioned,

ftnote 150.

cuspidata, Bosc, 149; distrib.,

156, 157.

pyramidata, Browne,

distrib., 155-157.

Clione, Pullas, mentioned, 149,

antarctica, H. A. Smith, men-

tioned, 151.

aurantiaca, Gegenbaur,

tioned, 150.

Forbes, mentioned,

149 ;

men-

Clione caudata, MacDonald, men-

tioned, 150,

limacina, Phipps, mentioned,

150, 151.

longicaudata, Souleyet, men-

tioned, 150.

punctata, Z'esch., mentioned,

150.

Clionide, 150.

Clionopsidee, 150.

Clydonia borealis, Sars, 28.

gracilis, Dana, 2+.

Clydoniide, 18.

Colloid Radiolaria, by R. Norris

Wolfenden, 131-135.

Collozoum, Haeck., mentioned, 131.

Brandti, Wolfenden, 131; men-

tioned, 135.

inerme, Haeck., 131; mentioned,

133, 135.

Colobonema sericcum, Vanhoffen,

172; mentioned, 164; distrib.,

186, 187.

Colunbella costulata, | Contraine,

140.

haliaéti, Jeffreys, 140, fig. 152;

distrib., 155.

rustica (Linn.), mentioned, 140,

151.

Conchoderma virgata, Spengler, men-

tioned, 43.

Concheecia B., Fowler, 254.

C., Fowler, 255.

acuminata, G. W. Mueller, men-

tioned, 229.

alata, G. W. Mueller, mentioned,

229.

ametra. G. W. Mueller, 229,

259; distrib., 298, 301;

mentioned, 220, 245,

300, 307-313.

bispinosa, G. W. Mueller, men-

tioned, 229, 255.

258,

brachyaskos, G. W. Mueller,

231, 259, 284; distrib.,

298, 300, 301, 307, 308-313;

mentioned, 220, 228, 245,

246.

castanea, G. W. Mueller,

distrib., 300, 301.

cophopyga, G. W. Mueller, men-

tioned, 246.

ctenophora, 6. W. Mueller, 240 ;

distrib., 300;

227, 241.

mentioned,

Concheecia cucullata, G. W. Mueller,

distrib., 300, 301.

curta, Lubbock, 231, 232, 259,

284; mentioned, 220, 227,

229, 245, 258, 273, 307-

313; distrib., 298, 300, 301,

304, 305-307; mentioned,

229, 293, 295, 302-304.

daphnoides, Claus, 233, 261;

distrib., 300, 301, 304

313; mentioned, 220, 227,

229, 240, 245, 258, 286,

307-313.

var. major, Howler, men-

tioned, 227.

var. minor, G.W. Mueller,

262; mentioned, 227, 233,

262.

—— var. typica, G. W. Mueller,

mentioned, 262.

decipiens, G. W. Mueller, 246,

270, 271; mentioned, 227,

928

dentata, G. W. Mueller, men-

tioned, 229.

dorsotuberculata, G. W. Mueller,

mentioned, 254, 255.

elegans, Sars, 233,263; distrib.,

300, 301, 304, 305, 306;

mentioned, 220, 228, 234,

245, 258, 307-313.

globosa, Claus, 295; distrib.,

300-302, 304, 306, 307, 301-

Bilioe

haddoni, Brady § Norman, 235,

264, 287; distrib., 300, 301,

304; mentioned, 220, 229,

236, 245, 255, 258, 282, 306,

307, 808-313.

hyalophyllum, Claus, 236, 265,

287; distrib., 300, 301,

304, 305; mentioned, 220,

227, 237, 244, 245, 258, 266,

306, 307-313.

imbricata (Brady), 238, 266,

288; distrib., 300, 301,

304, 305, 307; mentioned,

220, 224, 225; ftnote 226,

929, 240, 245, 258, 287,

306-312.

incisa, G. W. Mueller,

tioned, 255.

inermis, Claus, 239, 267; dis-

trib., 301; mentioned, 220

228, 245, 288.

men-

Conchecia kampta, G. W. Mueller,

240, 288; distrib., 300, 301;

mentioned, 220, 229; ftnote 245,

248, 272.

lacerta, Brady & Norman, men-

tioned, 227, 229, 233, 262

= daphnoides.

lophura, G. W. Mueller, 236 ;

distrib, 300; mentioned,

227, 265.

loricata, Claus, 240, 267, 289 ;

distrib., 300, 301, 3804;

mentioned, 220, 227, 229,

242, 245, 248, 258, 306-313.

var, minor, G. W. Mueller,

mentioned, 249-242.

240; mentioned, 241, 242.

macrocheira, G. WV. Mueller, 242;

mentioned, 227, 229, 243,

254, 268.

macromma, G.

mentioned, 249.

magna, Claus, 242, 268, 289 ;

distrib., 300-304, 307 ; larvae

W. Mueller,

of, 291; mentioned, 220;

ftnote 223, 227, 229, 237,

238, 241, 248, 244, 245,

252, 254, 258. 263, 266,

268, 287, 291, 306-313.

mollis, G. W. Mueller, men-

tioned, 229, 245, 272.

obtusata, @. W. Mueller, men-

tioned, 229,

orthotrichota, G. W. JMnueller,

mentioned, 255.

pellucida, G. W. Mueller, dis-

trib., 300, 301.

porrecta, Claus, 252, 276, 294;

mentioned, 227, 229.

procera, G. W. Mueller, 246;

distrib., 300, 301, 304;

mentioned, 220, 227, 228,

231, 233, 234, 245, 258, 270,

292, 306-313;

in ftnote 299.

pusilla, G. IW. Mueller, 247,

292; distrib., 298, 300, 301,

307; mentioned, 220, 229,

245.

var. major, G@. W. Mueller,

247, 272, 292; mentioned,

229.

var, minor, /ouwler, men-

tioned, 272.

mentioned

var, typica, G. W. Mueller,

INDEX.

Concheecia rhynchena, G. W. Mueller,

248, 272, 293; distrib., 298,

300, 301, 808; mentioned, 220,

229, 245, 258, 272, 307, 313.

rotundata, G. W. Mueller,

273, 293; distrib.,

300-307; mentioned, 220,

221, 229, 245, 249, 255, 258,

260, 263, 284, 285, 295, 306-

298,

249, |

315,

spinifera, Claus, 251, 274, 294; |

distrib., 300, 301, 304, |

305, 307; mentioned. 220, |

228, 233, 234 245, 258 |

306-318.

spinirostris, Claus, 252, 276,

294; distrib., 3800, 301,

304, 307: mentioned, 220,

9°07

227, 229, 233, 245, 253,

276, 282, 306-313.

258,

stigmatica, G. W. Mueller, 231; |

distrib., 300;

227, 230, 232.

221,

mentioned, |

subarcuata, Claus, mentioned, |

242, 243, 244.

loda, G. W. Mueller, 258,

295; distrib, 300, 301;

mentioned, 220, 229, ftnote

245-248, 272.

zetesios *, G. H. Fowler,

254,

277, 294; distrib., 300,

301, 304; mentioned, 220,

ftnote 223, 229, 245,

307, 308-313.

‘“B” innominata, mentioned,

220.

306,

innominata, mentioned,

220.

Conger leptocephalus, Gi//2, larva |

of, mentioned, 197.

vulgaris, Cuvier, 197, 203,

204.

Coralliophila, Adams, mentioned,

140.

edonus, Watson, mentioned,

139.

alucoides, Blainville, mentioned, |

139.

basileus, Dantzenberg & Fischer,

mentioned, 139, 140.

lactuca, Dall, mentioned, 140.

lamellosa, Jan., mentioned,

139.

(2)) ‘Spaeas, 139; fiz. 152;

distrib., 154, 156, 157.

361

Coralliophila(?), sp. B, 139, fig. 152 ;

distrib., 154, 156, 157;

tioned, 15].

Corophiide, 18.

Cranchia megalops, Prosch, 161.

Cranchiidarum, Hoyle,

162.

Cunanthide, 177.

Junina, Lschscholtz, mentioned, 164,

178.

proboscidea, etschn.,

tioned, 164.

Cunina-bud, development, 178.

men-

nomen,

men-

larvee, 178.

Cunoctantha fowleri *, Browne, 177;

mentioned, 164, 178, 180, 186,

187.

Cyclomyaria, 89.

Cymbonectine, 340.

Cymbuliide, mentioned, 147, 148.

Cyphocaris, Boeck, 14.

anonyx, Boeck,

mentioned, 13.

micronyx, Stebbing, 14; men-

tioned, 15.

Cypridina castanea, Brady, 257 ;

mentioned, 220, 279.

Cypridinidze, 220, 257, 279.

obesa, Vavrd, mentioned, 257.

14, 47, 50;

Cypris-larva of Lepas pectinata,

mentioned, 14,

Decapoda, by Stanley W. Kemp,

205-215.

their Distribution, by Dr. G.

Herbert Fowler, 215-217.

Dexiobrancha, Bows, mentioned,

150.

Diphyes, Cuvier, 343; mentioned,

344, 347.

acuminata, Leuckart, 344.

acuta [ Bigel.?* |, nomen, men-

tioned, 347.

appendiculata, Eschscholtz, 344 ;

mentioned, 3845-347, 352,

353; eudoxid of, mentioned,

354.

arctica, Chun, mentioned, 347,

bipartita, Costa, 344; men-

tioned, 347.

brage, Vogt, 341.

chamissonis, ualey, mentioned,

347.

58*

362

Diphyes elongata, Hyndmann, 344.

elongata, K. E, Schneider, 343.

fowleri*, Bigelow, 344, 346;

mentioned, 347, 352, 354,

357.

gracilis, Gegenbaur, 344,

kochii, Will, 340.

prayensis, Quoy § Gaimard,

yuentioned, 342.

pusilla, WeCrady, 344.

seeboldii, Geyenbawr, mentioned,

347.

sieboldii, Kolliker, 344.

steenstrupii, Glegenbaur, 347.

subtilis, Chun, 343; mentioned,

344, 347, 354, 358,

subtiloides, Lens g¢ van Riems-

dijk, mentioned, 346, 347,

348, 352, 358,

Diphyide, 341; mentioned, 340.

Diphyopsine, 343; mentioned, 347,

348.

Diphy opsis,

347.

diphyoides, Lens § van Riems-

dijk, mentioned, 347.

dispar, Cham. § Hys., men-

tioned, 347.

Haeckel, mentioned,

hispaniana, ayer, mentioned, |

347,

mitra, ualey, mentioned, 347.

Distribution, Bathymetric, 352.

Doliolum denticulatum, Quoy &

Gaimard, mentioned, ftnote 91,

93, 97, 98.

Ehrenbergi, Uljanin, men-

tioned, ftnote 91, 97, 98.

Krohni, Herdman, 90;

tioned, ftnote 89, 91, 92, 93,

97, 100.

Miilleri, Avrohn,

ftnote 91, 97, 98.

mentioned,

nationalis, Borgert, 90; men-

tioned, 89, 92, 93, 100.

rarum, Grobben, mentioned, 90. |

sp., Borgert, 90, 91, 93, 100.

Tritonis, Herdman, 89, 91, 92,

93, 97, 100.

Doratopsis sp., 161.

Doromasia picta, Chun, mentioned,

347.

Echinospira, Avohn, mentioned, 138.

compressa, Bianco, mentioned,

142.

men-

INDEX.

| Echinospira diaphana, Avohn, men-

| tioned, 143.

| Elaphocaris, Dohrn, caught, men-

| tioned, 206.

| Eledonella

160.

Embolus triacanthus, Fischer, men-

tioned, 146.

Embryo with

162.

Entomostraca, section of Branchio-

poda, 41.

sp., 150; mentioned,

yolk-sac

Ephyre, distrib., 186, 187; stages,

Erswa pyramidalis, Will, men-

| tioned, 340.

| Ethella, Adams, mentioned, 138.

| Euchetomera, Sars, mentioned, 104.

| fig. 105, 112, 113, 117.

tenuis, G. O. Sars, mentioned,

104.

Eucopia

107; mentioned, 110, 112, 113,

117; distrib., 129.

Eucopide, 170.

Euphausia Miilleri, Claus, 106:

mentioned, J09, 110, 111-114,

118; distrib., 122, 125, 127,

129%

pellucida, G. O.

mentioned, 109,

Euprimno, Boyallius, 38.

Sars, 114;

macropus, Bovallius, 38.

Eusiride, 15; mentioned, 14.

| tioned, 14.

mentioned, 14, 45, 46, 50.

| Eusirus, Ardy., mentioned, 15, 16.

Enuthemistro, Bovallius, 37.

bispinosa, Sars, mentioned,

38.

Eusirogenes, Stebbing*, 15; men- |

dolichocarpus *, Stebbing, 15; |

| Mortunatu lepisma, Chun, 25

attached, |

Fish-larvee, of uncertain position,

200.

Fishes of the Bay of Biscay, by

KE. W. L. Holt and L. W. Byrne,

189-201.

Note by G. H. Fowler, 201-

204.

ell =

mentioned, 26,

Fortunate, 18.

| Fowler, G. Herbert, Distribution of

Fowleri, Holt § Tattersall, 104,

unguiculata, Wll.-Suhn, |

the Amphipoda and Cladocera,

46-54; Chetognatha, 55-87 ;

Decapoda, their distribution, 215—

217; Distribution of Meduse of

the Bay of Biscay, 182-187;

Distribution of the Mollusca of

the Bay of Biscay, 154-157;

Fishes of the Bay of Biscay, 201—

204; Methods and Data, 1-11;

Notes on the Colloid Radiolaria,

133-135; Ostracoda, 219-336;

Thaliacea, 89-102; Vertical Dis-

tribution and Movement of the

Schizopoda, 122-130.

Fowlerina *, Pelsencer, 149.

Zetesios *, Pelseneer, 149, fig.

153, distrib., 156, 157 ; men-

tioned, 151.

Galeolaria truncata, Sars, mentioned,

347.

turgida,

347.

Galeolarine, mentioned, 348.

Ganmarellus crassicornis, Herbst, 24.

Gigantocypris pellucida, G., W.

Mueller, 257, 296; mentioned,

220.

agassizli, G, W, Mueller, men-

tioned, 257.

Gegenb., mentioned,

| Gleba eacisa, Otto, 350,

compressa (Gés), 38, 50; men-_

tioned, 13.

| Evadne, Lovén, 41.

Nordmanni, Lovén, 42, 52, 54; |

mentioned, 13.

spinifera, P. HK. Miiller, 42;

mentioned, 13,

tergestina, Claus,

42,

mentioned,

Females and males, Proportion in

Ostracoda, 308.

hippopus, Forskal, 350,

Gnathophausia zoéa, Suhm, men-

tioned, 107.

Gonostoma bathyphilum (Vaillant),

194; mentioned, 196, 208, 204.

microdon, Giinther, 194; men-

tioned, 196, 208, 204.

Gonostomatine, 194, 196.

Gossca corynetes, 1. Agassiz, men-

tioned, 165.

Gymnosomes, 149.

Haliscera,

174.

Vanhéffen, mentioned,

Halocypride, 220, 228, 259, 283; |

development, 281; mentioned,

279.

Halocypris globosa, Claus, 255;

mentioned, 220, 303.

Halopsychide, 150.

Halopyramis, Chun, mentioned,

338.

Hemimyaria, 99.

Heétéropode, 143.

Hippolytide, mentioned, 205; larva |

of, 214.

Hippopodius, Quoy et Gaimard, 338,

350; mentioned, 351.

gleba, Leuckart, 350.

hippopus, A. C. Schneider, 350 ;

mentioned, 352;

352, 358.

luteus, Quoy et Gaimard, 350.

mediterraneus, Costa, 350.

neapolitanus, Kélliker, 350.

pentacanthus, Claus, 351.

Holt, KE. W. L., & L. W. Byrne,

Fishes of the Bay of Biscay, 189--

204.

Schizopoda, 103-121.

larva of,

Homarus americanus(J/.-Edw.), 279;

Herrick’s record of, 279.

Homeeonema platygonon, Maas, 174;

distrib, 175, 186, 187;

tioned, 164.

typicum,

172.

Hoyle, William E.,

159-162.

Hydroida, 171.

Hydromeduse, 170.

Hymenodora glacialis, Buchholz, 213;

mentioned, 205, 216, 217.

Hyperia, Latreille, 28, 33; men-

tioned, 28, 36,

bengalensis, Giles, mentioned,

ttnote 35.

cornigera, M.-Edwards, 24.

dysschistus, Stebbing, men-

tioned, 35.

Fabrei, Milne-Edwards,

tioned, 33, 35, 36.

galba, Montagu, mentioned, 35.

hydrocephala,

tioned, 35,

luzoni, Stebbing, 33, 50; men-

tioned, 13, 34, 35, 37.

macrophthalma, JVosseler, men-

tioned, 35,

men-

Maas, mentioned,

Cephalopoda,

Stebbing, men-

men-

INDEX.

Hyperia medusarum, O. /. Mueller,

mentioned, 85,

oblivia, Kroy., 36.

schizogeneios, Stebbing, men-

tioned, 35,

sibaginis, Vosseler, 35; men-

tioned, 34.

spinipes, Boeck, mentioned, 35.

var.

35; mentioned, 34.

Vosseleri, Stebbing*, mentioned,

34.

| Hyperide, 18, 28, 33; mentioned,

| te

Hyperioides, Chevreuv, 34.

longipes, Chevreuv, 35, 49, 50,

53; mentioned, 13, 14, 34,

36, 46.

sibaginis, Vosseler, 49.

longipes, Vosseler,

Ischyroceride, 17; mentioned, 17.

Japetella, Hoyle, mentioned, 159.

Jasonilla, MacDonald,

138.

| Jassa, Leach, 17; mentioned, 14.

pulchella, Leach, 17; mentioned,

14, 47, 50.

Kemp, Stanley W., Decapoda, 205-

215.

Krohnia hamata, Moebius, 74, 85;

mentioned, 55, 68, 77, 81, 83, 84.

pacifica, Aida, mentioned, 79.

subtilis, Grassi, 78 ; mentioned,

83, 86.

var., JJoebius, 77; men-

tioned, 55, 86.

Lamellaria, Mont., mentioned, 143,

144,

perspicua, Vorbes § Hanley,

mentioned, 143.

sp. A, 142, fig. 152;

156, 157.

sp. b, 143, fig.

156, 157.

tenuis, Jeffreys, mentioned, 143.

distrib.,

152; distrib.,

Lamellariide, 142; distrib., 156,

157.

Lamellibranch larva, distrib., 156,

157.

Lamellibranche, 151,

| Lanceola, Say, 23.

mentioned, |

363

Lanceola estiva, Stebbing, 29, 50;

mentioned, 13.

Clausii, Bovallius, mentioned,

29.

curticeps, Bovallius, mentioned,

29.

felina, Bovallius, mentioned, 29,

30.

Lovéni,

29, 30.

Murrayi, Norman, mentioned,

29, 30.

pacifica, Stebbing, 30, 50; men-

tioned, 13, 29.

pelagica, Say, mentioned, 29.

Sayana, Bovallius, mentioned,

29, 30.

serrata,

29, 30.

Suhmi, Stebbing, mentioned, 29.

Lanceolide, 13, 17, 28.

| Larva allied to Caricyphus, Spence

Bate, 213, 214.

Larvee, long-anal, 200, 203, 204.

“*Prescope,” 195, 199, 203, 204.

Trigloid, 201, 203.

Scorpeniform, 201, 203.

_ Larval Brachyura, 215-217.

Sergestide, 206, 216, 217.

Lepadide, 42.

_ Lepas anserifera, Linn., pupa stage

of, 44.

australis, Claus, Cypris-larva of,

mentioned, 44.

Bovallius, mentioned,

pectinata, Spengler, Cypris

stage of, 42; mentioned, 13,

14, 43.

Leptomedusee, 165, 170.

Lilyopsis diphyes, Chun, 341.

Limacina antarctica, Hooker, men-

tioned, 147.

helicina, Phipps, mentioned, 147.

retroversa, //eming, 149; dis-

trib.; 156, 157:

triacantha, Pels., mentioned,

146.

Limacinide, 148.

| Liriantha tetraphylla, Haeckel, men-

tioned, 165,

Liriope, Lesson, mentioned, 164,

tetraphylla, Gegenbaur,

tioned, 165.

* Long-anal” larva, 200, 203, 204.

Lunatia, Gray, mentioned, 141.

Lysianasside, 14.

men-

364

MacGillivraya,

138.

“‘Macrochera,” distrib., 300.

Macrura, 206 ; free-swimming, men- |

Forbes, mentioned, |

tioned, 205.

Males, proportion

Astracoda, 308.

Margelis autumnalis, Browne*, dis-

trib., 186, 187; mentioned, 165.

Margelliidee, 170. |

Marmanema manmeeforme, Haeckel, |

ral |

“Mastigopus” stage of Sergestes,

4 oa

to females in |

mentioned, 206,

Maurolicus borealis, Nilsson, 194,

203, 204.

larva, 194; mentioned, |

19a:

Medusie, bibliography, 181; on col- |

lecting and preserving, 166-170; |

comparison from Bay of Biscay and

English Channel, 165-166; found |

in Bay of Biscay, by Edward T.

Browne, 163-181; note on distri-

bution, by G. Herbert Fowler,

182-187; table of contents, 163.

Meganyctiphanes norvegica, J/. Sars,

106; distrib., 124, 129; men-

tioned, 108, 109, 112, 118, 115,

i).

Mollusca (excl. Cephalopoda) of the

Bay of Biscay, by Paul Pelseneer,

137-153; Note on Distribution,

by G. H. Fowler, 154-157 ; table

of contents, 137.

Monophyes diptera, Haeckel, 343.

gracilis, Chun, 343.

irregularis, Chun, 343.

Monophyide, 338; mentioned, 339.

Muggiea, Busch, 340.

atlantica, Cunningham, men-

tioned, 341, 347.

Kochii (Will), Chun, 340;

mentioned, 341, 844, 347, |

352, 354, 358.

pyramidalis, Busch, 340.

Narcomeduse, 177.

Nassa, Lam., mentioned, 140.

Natica, Adams, mentioned, 151.

greenlandica, Z’rosch., mentioned, |

141. |

helicoides, Zrosch., mentioned, —

141.

lactea, 77 osch., mentioned, 141. |

INDEX.

Natica nana, JZovén, mentioned,

141.

pallida, TZvrosch., mentioned, |

141.

sp., 141, fig. 152; distrib., 156,

157.

subplicata, Jeffreys, mentioned,

141.

Naticina, Gray, mentioned, 141.

Nausithoe punctata, Aolliker, men-

tioned, 345.

| Nectopyramis *, Bigelow, 338 ; men-

tioned, 337, 339, 352.

thetis *, Bigelow,

tioned, 337, 357.

Nematobrachion bodpis, Calman,

107; mentioned, 111-113, 116.

| Nematodactylus boépis, Calman, 146.

Nematoscelis megalops, G. O. Sars,

106; distrib, 125, 127, 129;

mentioned, 110, 112, 118, 115,

120, 123.

Nerophis sequoreus, var. exilis, Holt

§ Byrne, 200, 208, 204.

Notobrancheide, 150.

Obelia lucifera, Haeck., 170; dis-

trib., 186, 187; mentioned, 165.

Onychoteuthis sp., 160.

Ostracoda, by G. H. Fowler, 219-

336; vertical distrib., 296-304.

—— individual species, 300.

Pagurid metazoza caught, 214.

Paraclione, Z'’esch., mentioned, 150.

Parahyperia, Vosseler, 34, 35.

Parascina*, Stebbing, 20; mentioned,

13.

Fowleri*, Stebling, 21; men-

tioned, 13, 45, 50.

Parathemisto, Boeck, 36; mentioned,

13.

abyssorum, Boeck, 36.

oblivia (Kroy.), 36, 49, 50;

mentioned, 13, 37, 46.

| Pegantha sp., 178; distrib., 186,

187. :

Pelagia, “‘Ephyra” stage, 179.

Pelseneer, Paul, Mollusca (excl.

Cephalopoda), with a Note on Dis- ,

tribution, by G. Herbert Fowler,

137-157.

338; men- |

Peraclis, Forbes, mentioned, 151.

brevispira*, Pelseneer, 146;

distrib., 154-157; men-

tioned, 148, fig. 153.

| triacantha, Mscher, 146; distrib.,

| 156, 157; mentioned, 147,

148, fig. 153.

Periphylla, Steenstrup, mentioned.

165.

hyacinthina, Steenstrup, men-

| tioned, 179.

sp., 179; distrib., 186, 187.

| Periscope” larva, 199, 203,

204,

| Pheodarian Radiolaria, branching

| spines, 352.

| Photichthys, Hutton, mentioned,

| ef

Phronima, Latreille, 32 ; mentioned,

13.

sedentaria, Latreille, 32-50.

| Phronimide, 32.

Phrosinidx, 38.

Pneumonoderma,

150.

Pneumonodermatidix, 150.

Podocerus falcatus, Sars, 17.

Polyphemidie, 41.

Polyphyidee, 350.

‘** Preescope ” larva, 195, 203, 204.

Praya, Blainv., mentioned, 359,

cymbiformis, Leuchurt, men-

tioned, 339, 342.

diphyes, Kolliker, 341; men-

tioned, 342, 343.

filiformis, Keferstein & Ehlers,

341,

maxima, Gegenbaur, mentioned,

| 342, 343.

| Prayine, 341; mentioned, 339.

Primno, Guérin, 38; mentioned, 14,

15, 40.

| antarctica, Bovallius, mentioned,

39.

Latreillei, Bovallius, mentioned,

| 39.

lutescens, Guérin, mentioned,

38.

macropa, Guérin, 38, 50°; men-

tioned, 15.

Cuv., mentioned,

Meneyillei, Bovallius, men-

tioned, 39.

Pseudomurex, Monterosato, men-

tioned, 139,

basileus, Dantzenberg & Fischer,

mentioned, 139, 140.

Radiolaria, Colloid, by R. Norris

Wolfenden, 131-135; Notes, by

G. H. Fowler, 183-135,

Radiolaria, Phweodarian, mentioned,

352.

Rhizophysa filiformis, Della Chiaje,

341.

Rhizophysaliw, 352.

Rhizophysid fragment, mentioned,

352, 354.

Rhopalonema, Gegenbaur, mentioned,

173, 174.

ceruleum, Haeck., 172; men- |

tioned, 164, 165, 174; dis-

trib., 182, 186, 187. |

funerarium, Vanhoffen, men- |

tioned, 174.

Rosacea, Quoy et Gaimard, 341;

mentioned, 339.

ceutensis, Blainville, pt., 341.

ceutensis, Quoy et Gaimard,

341. |

diphyes, Graeffz, mentioned, |

342, 343.

medusa, Metschnikoff, men- |

tioned, 342.

plicata, Quoy et Gaimard, 341 ;

mentioned, 339, 342, 343,

352, 354, 358.

rosea, Chun, mentioned, 342.

Sagitta Bedoti*, Béraneck, men-

tioned, 67. |

bipunctata, Quoy et Gaimard,

69; mentioned, 55, 67, 70,

72-74, 83, 86.

decipiens *, Fowler, 70; men-

tioned, 55, 71, 81, 83, 84, 86.

elegans, Verrill, mentioned, 67,

(23513:

flaccida, Conant, mentioned, 72,

73.

furcata, Sleinhaus, 63; men-

tioned, 55, 71-74, 79, 81, 82,

83, 84, 86.

hexaptera, Orb., mentioned, 73.

hispida, Conant, mentioned, 67,

125 tds

lyra, Avohn, mentioned, 64.

macrocephala*, Fowler, 65;

mentioned, 55, 67,71, 81, 83,

84, 86.

magna, Langerhans, mentioned,

Tos

neglecta, Aida, mentioned, 72.

INDEX.

Sagitta pulchra, Doncaster, mentioned,

planctonis, Stetuhaus, 71; men-

tioned, 55, 72, 86.

regularis, Aida, mentioned, 72.

serratodentata, Avohn, 58, 85;

distrib., 123; mentioned,

OD, dO OU MGVAm MOO.) 710;

79, 81, 82, 83, 84, 86, 95,

96.

sp. ined. (?), juv., 71, 86.

tenuis, Conant, mentioned, 72,

73.

tricuspidata, Aent, mentioned,

73.

Zetesios*, Fowler, 67;

86,

men- |

tioned, 55, 71,77, 81, 83, 84,

Salpa democratica-mucronata ?, or-

skdl, 99, mentioned, 89, 101.

echinata, Herdman, 99; men- |

tioned, 89, 100, 101.

? fusiformis, var. echinata,

Apstein, 99.

runcinata - fusiformis, Cham.

Cuv., 99; mentioned, 89,

100, 101.

Schizobrachium, Metsenheimer, men-

tioned, 150.

Schizopoda. by E. W. L. Holt and

W. M. Tattersall, 103-121; on

Vertical Distribution

ment, by G. H. Fowler,

130.

Scina, Prestandrea,

13.

acanthodes, Stebbing, 18; men-

tioned, 22.

atlantica, Bovallius, mentioned,

24.

and Move-

122

99.

“45

mentioned,

borealis, Sars, 28, 50;

tioned, 13, 23, 26, 48.

Bovallii, Vosseler, 26, 27.

men-

Chuni, Garbowski, mentioned,

23.

Clausii, Bovallius, 48; men-

tioned, 23, 26, 27.

concors, Stebhing, mentioned, 23,

cornigera, Stebbing, 24.

crassicornis, /ubricius, 24, 47,

48, 50; mentioned, 13, 23.

Ldwardsi, Garbowski, 24.

ensicorne, Prestandra,

tioned, 25.

men-

incerta, Chevreww, mentioned.

23, 26.

365

Scina Lamperti, Vosseler, mentioned,

23, 28.

lepisma, Chun, 25, 50 :

mentioned, 13, 23, 26, 27, 45.

longipes, Dana, mentioned, 23-

25.

marginata, Bovallius, 25, 50;

mentioned, 13, 23, 26.

cedicarpus, Stebbing, 25, 50;

mentioned, 13, 23, 24.

pacifica, Bovallius, mentioned,

EB},

Rattrayi, Stebbing, 26,50; men-

tioned, 13, 23, 26, 27.

Sarsii, mentioned,

24,

similis,

23.

spinosa,

23.

stenopus, Stebbing, mentioned,

23, 24.

ay.

Bovallius,

Stebbing, mentioned,

Vosseler, mentioned,

Tullbergii, Bovallivs, men-

tioned, 23.

uncipes, Stebbing, mentioned,

23.

Scinidw, 13, 17; 18.

Scopelid larva, 198.

Scopelidee, 197.

Seopelus, Cuvier, mentioned, 191.

glacialis, Reinhardt, 197; men-

tioned, 198, 199, 203, 204.

Rafinesqui, Cocco, 197, men-

tioned, 199, 203, 204.

punctatus (2tafin.), mentioned,

ftnote 199.

Scorpena, Zinn., mentioned, 201.

dactyloptera, La Roche, men-

tioned, 201.

“ Scorpeniform ” larva, 201, 203.

Scyphomedusie, 17%).

Sergestes arcticus, MArdy., 206;

mentioned, 205, 216, 217.

Sergestidx, larval, 206, 216, 217.

Sigaretus, Lam., mentioned, 140.

Sinusigera, Ovb., mentioned, 138.

Siphonophora, by Henry B. Bigelow,

337-368,

Sirinthea — enryyaster, Gegenbaur,

LAL.

Solarium, Zan., mentioned, 142,

Lode

architwe, Costa, mentioned, 142.

fallaciosum, Z'iberi, mentioned,

141(=8. siculum, Contraine),

142,

366 INDEX.

| Tattersall, W. M., and Holt, E, W.

Schizopoda, 103-121.

Solarium pseudoperspectivum,

Brocchi, mentioned, 142.

siculum, Contraine, mentioned, |

142.

?ap., 141, fig. 152;

156, 157.

Solmaris corona, Haeckel, mentioned,

165.

Solmundella

186, 187.

Spheronectes, Huvley, mentioned,

338, 340.

Spheeronectine, 338,

Spherozoum punctatum, J. Mueller, |

131, mentioned, 135.

Spongiobranchea, Orb., mentioned,

150.

Stebbing, Rey. T. R. R., Amphipoda

sp., 161.

Thalassicola,

131, 132.

nucleata, Huwley, 132; men-

| tioned, 133, 135.

Thaliacea, by G. H. Fowler, 89-102.

Thaumantias lucifera, Forbes, 170.

Thécosomes, 146.

Themisto, Guérin, mentioned, 37.

bispinosa, Boeck, mentioned, 38.

compressa, Goes, 38,

distrib., Huxley, mentioned,

sp., 179; distrib.,

38.

Thliptodontids, 150.

Thyrostraca, 42.

and Cladocera, with Notes on Thyrostracan Larva from the Bay

their Distribution, by G. H. of Biscay, 14.

Fowler, 15-54. | Thysanoéssa gregaria, G. O. Sars,

Stephanophyes, Chun, mentioned, | 106; mentioned, 112, 113.

340. | longicaudata (Arédy.), men- |

superba, Chun, mentioned, 339, | tioned, 107.

355, | neglecta (Avoy.), mentioned,

106, 115.

parva, Hansen, mentioned, 106.

Thysanopoda bidentata, G. O. Sars,

114.

microphthalma, G. 0. Sars,

106; mentioned, 112-114,

norvegica, G, O. Sars, 116.

Tima, Hschsch., distrib., 186, 187;

mentioned, 165.

| sp., 170.

Trachomedusa, 164, 171.

Sternoptychine, 193.

Stomias boa, Risso, 193, mentioned,

198, 203, 204.

193 ;

Stomiatide, mentioned,

201.

Stomiatine, 193.

Stylocheiron abbreviatum, G7, 0. Sars, |

107; distrib., 129; mentioned, |

108, 110, 112, 118, 116. |

chelifer, Chun, 107, 117.

longicorne, G. O. Sars, 116;

mentioned, 107.

mastigophorum,

mentioned, 107.

Suhmii, G. O. Sars, 107; dis-

trib., 126-129; mentioned, |

HOS=AA3! 1G acl 7A A, pl

Syngnathidee, 200. |

Syngnathus, Latreille,

200.

Systellaspis debilis, A. Milne-Hdw.,

mentioned, 205.

171; distrib.,

tioned, 164.

Trachynemidz, 171.

Chun, 116; 186, 187;

densistriata, Jeffreys, 139.

fimbriata, Jeffreys, 139.

“ Trigloid ” larva, 201, 203.

Trypanosphera brachysiphon, Cleve,

mentioned, 133.

mentioned,

ity, |

Teleoteuthis caribrea, Lesuewr, 160. |

crassicornis, Avdy., mentioned, |

Trachynema eurygaster, Gegenbaur, |

men- |

Trichotropis, Brod., mentioned, 139. |

Turritopsis, MeCrady,mentioned,178, |

‘yphidee, 40.

Tyro atlantica, Bovallius, 24.

borealis, Bovallius, 28.

cornigera, M.-Edwards, 24.

marginata, Boyallius, 25,

Sarsii, Bovallius, 24.

Tyronide, 18.

Velutella flexilis, Montagu, men-

| tioned, 143.

Vibilia, Wilne-Hdwards, 31.

armata, Bovalius, 31;

tioned, 13, 50.

Boyallii, Bonnier, mentioned, 31.

cultripes, Vosseler, mentioned,

men-

31.

dentata, Chevreuv, mentioned,

3l.

erratica, Chevreur, mentioned,

Sil

grandicornis, Chevrewv, men-

tioned, 31.

hirondellei, Chevreuw, mentioned,

Slie2:

Jeangerardii, Lucas, mentioned,

Sil By4

propinqua, Stebbing, 31; men-

tioned, 13, 32.

viatrix, Bovallius, mentioned,

31, 32.

Vibiliide, 13, 17, 31.

| Vogtia, Adlliker, 351.

| Kbllikeri, Haeckel, 351:

| pentacantha, <Adlliker,

mentioned, 302.

spinosa, Keferstein &§ Ehlers,

351; mentioned, 352.

ool;

Wolfenden, R. Norris, Colloid

Radiolaria, 131-135.

Yarrella, Goode § Bean, mentioned, ;

197.

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Part, X90 ss. LONG

Part XII. 1903. .... 0 10

Part XIII. Index. .. 0 2

IX. Part Py G0B cere OM)

Tebien ge IO TASTER oe Ae. (0) 8

Part), WS 1903.) 25) deel

Part IV. 1904...... 0°36

Part). . Vind'904 2.0056)

Part’ (Vil uo0A ey Ome

(In Progress.)

XX. Part (e9 0A er 0 ee

Part IL. 1904 .... 0 8

The prices of the

Zoological parts of those which have been published are as undermentioned (for the Botanical parts see Botanical

c=)

SSS S&S Sis te) Sen SiS ae eS SSF SS SS SSS SS — a)

. 0

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270 A i a ;

10 0

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9 0

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iv)

—— rs St—‘S; ;

2nd Ser. ZOOLOGY. | (VOL. X. PART 3.

THE

TRANSACTIONS

LIBRARY)|2

A Ot =

>, Mase O/

OF enn ey,

THE LINNEAN SOCIETY OF LONDON.

BISCAYAN: PLANKTON COLLECTED DURING A CRUISE OF

H.M.S. “RESEARCH, 1900,

Parr III.—THE CHATOGNATHA.

G. HERBERT FOWLER, B.A., Pu.D., F.LS., F.Z.S.

ON: eG: Ns

PRINTED FOR THE LINNEAN SOCIETY

BY TAYLOR AND FRANCIS, RED LION COURT, FLEET STREET,

SOLD Al THE SOCIETY’S APARTMENTS, BURLINGTON-HOUSE, PICCADILLY, W.,

AND BY LONGMANS, GREEN, AND CO., PATTERNOSTER-ROW.

January 1905.

em ot

on)

’

ee)

balay

ba wie

tales

sae

LINNEAN SOCIETY OF LONDON.

MEMORANDA CONCERNING TRANSACTIONS.

The First Series of the Transactions, containing both Botanical and Zoological contributions, has been completed

in 30 Vols., and a few entire sets are still for sale. Only certain single volumes, or parts to complete sets, may be

obtained at the original prices. The price of the Index to Vols. 1-25 is 8s. to the public, and 6s. to Fellows; to

Vols. 26-30, 4s. to the public, and 3s. to Fellows.

The Second Series of the Transactions is divided into Zoological and Botanical sections. The prices of the

Zoological parts of those which have been published are as undermentioned (for the Botanical parts see Botanical

wrapper) :—

Srconp SERIES.— ZooLoey, Szconp Sertus.—Zooroey (continued).

Volume, HE dice we the Price to Volume When Price to the Price to

Published. Public. Fellows. ; Published. Public. Fellows.

Ges. de SE seen: Sf Sess £ sade

I, Part Ly 1875..... 1 4 0....018 0) vy. Part geod. .... 0°2 6 22. Oe

Part WL 1875.....0 6 0-....0 4 6) vy pi 9M ago, .... 2 0 0 . sane

Part: * Es 18762 3.501) Se 0 ce Part 911894. .... 1 11 08... deem

Fart: DWolS77e.k- OTGe Ox 270) tea) Part IIE 1894..... 010 0 ....00) jane

De i ee ee eee Part TV, 1896.....1 4 0... O}1game

LE a Sata oo retee AY Ce Part Vi 1896.....-0 10 0 .... OUNamNe

Part, ov oS 7 Sona oo aelGe RO eee le Zant Part SHES 0 8

Bate Teer Ceuta ean an Part VIL 1896: .....0 12 0 .... Ongiea

I. vie ae aS aon ri hie 2 PartVIMG687. .... 0 2 6 ., OMSmNE

vie tak VIL Part -T)0896..... 010 0 0.10 eae

Sn Pel ead ee ida Me Part 1, 97,.... 012 0... eam

Part, “IV.s82. eeu 7 6 ue oe st

stat Cae ce eae ep Ma Part TT 1897.....0 6 0%... Ou

a get ancie Sane es DRE Part IV. 1898,....010 0....0 7 6

Part Wil: VebBiseg 0 50 eo. 0809 Part Vie: 0 18 Oe

nore omienaih se iene Ih ae ene Part VIL, 1889,.... 0 18 0 .... SOnaeeaiee

ae Neue ee Meat ame ee Part VIII. 1899..... 012 0....0 9 0

Part) RT Ge84, (0010.0... ONG Pert DG.) 0 0 an

Part. Kl, #985 5n2. 10,06> 0 242220 246 caine P00 ses. 0 6 0 een

Patt: RUE, ISB th 10976..0 2.2 Ome Part XT. 0G, 0 2 Oe oe

agi REV. 18S, 06 0, ord gh EE Banh, oa 010 0.... 0 9 7ame

es Pee nN Ne em me n oe | Part “TL 1900.0... 0 10. 0° 45 n0e teen

Re aR teehee Re a rs Part IIT. 19005. 0 10 0 a5 (Ou irane

Part RVI 1886). 2400) S00 oes Part IV. 1901..... 014 0.... 010 6

PartX VIII. 1888. ....0 2 6....0 2 0 Fort Vee oO ee

TIL Parte, siege. Gs Sadat 0 eel eae od a aoe sie ‘ hile : :

Pak nk 1866, an 01a a ee Oe

As ie ARM Ee Pari 1k. 100e) acc. 0 5 0%...5 OMeme

Bec ye ees eee Part X. 4008... 1 0 0°. 2. soeeee

Part WIS WRBR ae eee Ol. On naene Part) XD W908... 0 =6\) OTe se Ona

Part XIE 2908).... 0.10:-0)...-0negame

MCR ee Part KIIL Index. .. 0 2 9....0 2 8

ar bad sy fotiet’e te a er

oe ee a Pa ck D1 o| Ls Part 1. 1903.....0 9 0....0 6 9

oe tae Part) Uh 1903: ...< 0°18 100... wOlnenee

V. Part =‘. 1888..... 012 0....0 9 0 Part I. 1903.....- 1: 00 eueeonieeaa

Part’ Ul. 1888; 275105) 5- 0 agen ho Pact a 1904... Ot ee eee ee

Patt Wily 1680s.5,.00) 77 0 ee ETG Part’. /¥./1904. 4: 00° 6! Os, senpune

Part. IV. 1890, .,.. 019. 0, /5..0he a0 Bart “VE. 1904. v2.2 00 8 012k eee

ae Ea, Be ne ne iB ; : Part VIL. 1904 ..44 0-6) 0: goes

: aaah aot acta? Part VILL, 1904; .:,. 0920 “Oye aaa eins

Bart) AVI also ee oy: (Ol OnlO ee 0 een (In Progress.)

Part VIII. 1892. .... 0°8 0..2. 0 6° 0| -%: Part 1, 1904 oe nema eens ee

Part IX. 1892. .... 0112) 0° :.J00 9% mM Part. ‘TI, 1904 :42 O08 00% ek eee nee

Parti! aX: 1693)... 8) ee ee Part. TUL. 1005.2. 0. 9:0 en ee

2nd Ser. ZOOLOGY. | (VOL. X. PART 4,

THE

TRANSACTIONS

THE LINNEAN SOCIETY OF LONDON. .

BISCAYAN PLANKTON COLLECTED DURING A CRUISE OF

H.M.S. “RESEARCH, 1900.

Part 1V.—THE THALIAC7PA.

By G. Herpert Fow er; B.A., Ph.D., F.LS., F.Z.S.

Part V.—THE SCHIZOPODA.

By E. W. lL. Hort and W. M. Tarrersat., B.Sc.

With an Appendix by G. Herpert Fow.er.

Part VI—THE COLLOID RADIOLARIA.

By R. Norris WoLFENDEN, M.D., F.L.S., F.Z.S

L ONSEN :

PRINTED FOR THE LINNEAN SOCIETY

BY TAYLOR AND FRANCIS, RED LION COURT, FLEET STREET.

SOLD AT THE SOCIETY’S APARTMENTS, BURLINGTON-HOUSE, PICCADILLY, W.,

AND BY LONGMANS, GREEN, AND CO., PATERNOSTER-ROW.

November 1905.

The First Series of the Transactions, containing both Betanical and Zoological contributions, has been completed

Only certain single volumes, or parts to complete sets, may be

The price of the Index to Vols. 1-25 is 8s. to the public, and 6s. to Fellows; to

in 30 Vols., and a few entire sets are still for sale.

obtained at the original prices.

Vols. 26-30, 4s. to the public, and 3s. to Fellows.

LINNEAN SOCIETY OF

LONDON,

MEMORANDA CONCERNING TRANSACTIONS,

The Second Series of the Transactions is divided into Zoological and Botanical sections.

Zoological parts of those which have been published are as undermentioned :—

When Price to the

Volume. Published. Public.

Be th

I. Part imete¥psy eg tk Pe

Part 1G as, 36 on 0 6

ene MOE, Weil 54 a6 1 8

Parts le leider OMLo

Part Vien LS iiienstenetene Ommltss

oun NEG WEG ¢ oo tb 2

Part VII. 1878. 2 LG

Part, Ville s Tos Alen O

II. Part 1 asi) yl.

Part II. 1881 . 0 15

Part III. 1882 a, Ht}

Paré DVe 1882s 25.. 0 7

Part Venice emer 0 3

ieee Ol, fete soa 5 lO

Tei WIOI ee adao OO &

lene, WU, skh 5.4. OY 3

lean IDG ites sone 8)

Part XT LSBH cant 4.

Part XI, 1884. 5 (0) 1X0)

Pantene Sosa enlO mG,

vebiae DUIS UstsHS Bh WO)

Part ec liSGon we O uO

Part exXeVe) 1SShs een 0) et

Part XVI. 1885. =)

IR MOMIUE, stl, Googe OS

PartxXcVill, We8sen. a One

IlI. Part Te8S4., Soe al

Part Tl. 1884. iy at

Vein TMOG astsisy s54q il 10)

Party SLVelsSos we mS

Part AVES 7G Gee (0) <ce)

Part) | Vie UsS8iee..30) iG

IV. Part T1886. 25. Lore

Part ie Soyer

Bart SS Saieren-Orel(G

Ve Part lie Mltstetsh 5 4 35) I}

Part DV LSS882 eee Ono

Parti Sl eL8S 9 eel anags

Part IV. 1890. lO ale

Part Vi 89.0 ere Oma,

Parte. | Vile 189 aeemOnnle,

Jehay AMADA 6 o5 4 OG

Part VIII. 1892 50), sh

Part IX. 1892 Ole

Part EX; ALSOSS ea sleeS

Part XT 894% ee) ae

Srconp Srrres.— ZooLoey,

isSVeiio) is ta. Sle Se Cer =) Se Sr SaaS eee te Seo a)

SeocaaqaqgeoktooorPoOoOoOOoOrPrPr ooOoOoeoeoeooOeoeoeoseoeortooorocoroe ak

Price to

Fellows.

TOW we Ww WO

BRrOoonwnrranw NW We

w oOo wo =

WFO OR OO

eS Ol On Omos (> 1 On Care

See Oe SO Os Ooms Gn, 7 O05 kO) Os) Ca) 1G. Gd Oy Sd «C9 CD

SLOP Sooo yoo) Oo) oO

Srconp Srrtes.—Zooroey (continued).

Velie When Price to the

‘ Published. Public.

is:

Wile Bart MedS94.. 7... 2 0

Partials oterce. . i ela

Part iiesgie =... 0 10

Part Wyeei896; 4.2 1 4

Part @Well8960e. . 0-10

geyan AVI, ies, 45 gael

ParbmVillelSo6 tens.) 0! 12

Pant ViGMiegsoeeee 0 2

VIL. Part USO Ge 0) 10

Part) Wasson 0) 12

Part) JUSS eee 0 16

Part TVedeose.. . 0! 10

Part Wamlegsareace 0 18

Port Vieelsosies... 0: 13

Part Vilsis9oe.... 0 18

Pant Viiete gore... 0) 12

Part: UXeelsoomee... 1 0

Part XG aS00s ss. 0 6

Part Xiea900r =... 0 2

VIII. Part i UNOS 53 a5 ORO)

Part ste G00 eree 0) 10

Parte Tio Ofer 0) 0

Pants OVO Odeeece 0) 14:

Part \V, etgO01Reer 0 5

Part Virgigoeees. 0 10

Part Vii oui. 1 8

Part VIII; 1902555. 0 4

Part UX aS02meers. 0-5

Part” Xeai90steee. 1 0

Part, XT W90sae... 0 6

Part XO; Steere. Ol 10

Part XII index... 0° 2

DX Bart TealQ0ss. =... 0’ °9

Part; Tig0sy.. 3. 0 8

Part, TE a9035..5)- « 1 4

Parts LV 2904.".....'0 6

Part, Veel004e-e.... 0 16

Part: WileeloOdee. .. (046

Part VII. 1904..... 0 6

Part VIII. 1904. .... 0 10

Part Uxoaig04..... 0) 6

(In Progress.)

X. Part TL GOES severe oO ares

Part, Wilelo0s Oat

Part “LLL Q05nee.. adued

Parte Dy. LO0S' se 0 10

Sro ig

SSS SSS SSeS CSS Ce Sif oe SC 6S eS ees Gers) Sree SS —aee =

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Price to

Fellows.

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w ow - ©

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“1D om

=o OHO WARMTH COS HAAS D &D SAETDTRHAOAWASCA SCOOT AGTCAwWSR

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2nd Ser, ZOOLOGY. | (VOL. X. PART 5.

THE

TRANSACTIONS

LIBRARY

“ze SOS

a. 5

R -

face aS

5 hy

THE LINNEAN SOCIETY OF LONDON.

BISCAYAN PLANKTON COLLECTED DURING A CRUISE OF

IMS. “RESEARCH, 1900.

Part VIIL—MOLLUSCA (excluding Cernatoropa).

Dr. PAUL PELSENEER, Professeur i Ecole Normale de Gand.

With a Note on their Distribution, by G. Herserr Fowrer, B.A., Ph.D., F.L.S., F.Z.S.

L-O Noe Or N:

PRINTED FOR THE LINNEAN SOCIETY

BY TAYLOR AND FRANCIS, RED LION COURT, FLEET STREET.

SOLD AT THE SOCIETY’S APARTMENTS, BURLINGTON-HOUSE, PICCADILLY, W.,

AND BY LONGMANS, GREEN, AND CO., PATERNOSTER-ROW,

February 1906.

LINNEAN SOCIETY OF LONDON.

MEMORANDA CONCERNING TRANSACTIONS.

The First Series of the Transactions, containing both Betanical and Zoological contributions, has been completed

in 30 Vols., and a few entire sets are still for sale. Only certain single volumes, or parts to complete sets, may be

obtained at the original prices. ‘The price of the Index to Vols. 1-25 is ‘8s. to the public, and 6s. to Fellows; a :

Vols. 26-30, 4s. to the public, and 3s. to Fellows. E a é

The Second Series of the Transactions is divided into Zoological and Botanical sections. The prices of th

Zoological parts of those which haye been published are as undermentioned :—

Sreconp Srrrms.— Zooroey, Srconp Surtns.—Zooroey (continued).

When Price to the Price to When Price to the Pri

Volume. Published. Public. Fellows. Volume. Published. Publie. F

fi vst a: pe ceed Liss ids Le

Ir Parts L-VIUL 1875-79.. 810 0 .... 6 7 6) VI. Part /9W. 1896. .... 00 Onan

RL Park PaO H870ne 2 alles 10) Oe a0 Part VI. 1896.....0 8 0.... 0°

Part’ Tb 1881......0W5 0 oe 0M) We Part VII. 1896..... 012 0.... 0

Pantie We ASSO". Ae sles 90% week IanO Part VIII. 1897.....0 2 6.... 0

Part IV. 1882..... 0 7 6....0 5 6) VIT. Part! “2. 1896. .... 0 10) "0"aaaeuen

Part Ve 1S82se.%. pees ney area dale 2) Ss) Part ‘TE; 1897. .... 0 12) 0a

Part.) Vie 1888.5 eal 0, 0 2.4 O15 eeO Part TUT, 1897..... 0 6. 00=saamm

Part VI 1888: 2. 0.85. Oe 20 8e eg Part TV. 1898..... 0 10 0 <2. .m0Mm

Part VIII. 1883. .... 0. 3 0°... 0 2 3) Part @yede9s. .... 0 18. One

Pact) PAX S 1S8aycece.0) Gon es One ae Part “VI. 1898. .... 0 13. 0) Sam

Part XC Ae kOn eA Glee aR OME SENG Part Vile 1899. .... 0 18 0) -.eeOmn

Part’, Xd, 1SSdan = MONO ROC ngs, 0 eye Part VIII. 1899. .... 0 12 0 ..4.m0mm

Parts eX Tees oe 0) 60 een Part 1x a899, J... 1. 0 00 cone

PartyeX Ile p1684.4 2, 00)e0 le narra Part “e900. ..... 0 26 Oy eae

Part —UVesISeo. =. 0. et 0 see Ole tet Part “Xigei900.)..... 0 2) Ouaaeeme

Parts XV. 1885.:.-.-.0 £6 ).05+:0 3 0) ror. Part SemeoO ;4..70 10010 earn

Pht Misuse (seeing tah es Ai Part IL 1900..... 0.10 0 .... 0 samen

Parbexey Ue e1686.e: 280 we), HOw 0 2 eee Me a 4

Part RVI ESS, oe.) 10 Fe 66) eee 020 Gs i en 6

I. Part MEMS tent ay... ol 4 Om eel oO ae O: Part siVeulsole- 6.0. 5: 20m eeerO) tom

Part. WLS ASSt ee amd 2) 0 ener ae Part VI. 1901..... 010 0..., 0.

Part 1: 1885.9) 21810 JO eee ele Part VII. 1901......1 8 0.... Jn

Parti: eb VAWISS5- nae OY Marcos O 6 Part VII 1902)... 0 4 0 .. 220MM

Part VemSS 7a Or 6O Oger O a O mm Part. UXe 190282... 0 5 0.2. 20 monne

Part NUP WSeeh ese Oe Gy WP sade Oe 4b OS Part) Xeul903ee.. 1 0) Ou eeOn 0

IV. Part Ty 18865 seen 2. SORA EO ORD) Part XI. 1903..... 0 6° 0 ..., 00mm

Part Wi; ASSysbee- d 68 10cm eelount amo Part XUL Wosr.....0 10 0 .2. 30a

Part. MU Seseee0 16 OS eo mo mnO Part XIII, Index. .. 0 2 9..... 0 9m

We Ten Ise Gans OIE OW ead O 8 Oo TX. Part “Wedgostes.. 0) O10 see .n0mnGnE

Parti AL MISS8.xres ON 40). eealOs ug Part — T1908... 0 8 100. Same

Part TIT. 1889.....1 7 0....1 0 0 Part III. 1903. .... 1.4 0%, OnE

Lehn INS JEO; sono OU Osco @ B Oo Part v2 1904,.... 0 6 0 - oe Ome

lithine Mo wg OT soon O O OC Part Vileo04. ...- 0. 6 0 22.0 4a

Teepe NEUES WSS cage GF O ssa5 M 4h @ WEEK \WALE, GO ee OG nue 20 VAate)

Part VIII. 1892. .... 0° B70. eae) 16sa0 Part VIL 1904, ....0'10. 0,

Part, UX. 1892.5... 0)a2 5 ON ee Omn Os 0) Part. UX. 1904. ..<.40) 6) 0 Oe

Part. X. 1898.42..), al 2S \A0 ee aD (In Progress.)

Part; -XKT..1804: 4... 0 2 96 een een Xj Parsee, Mt 04, 0. a0 PA rep 0)

Vi. Part. 1.180%, in, 2) 10 SD seewennty) m Part II. 1904. .... 0.... 0%

Part’ “Tie 1894.55... 0 eae mie Part III. 1905. .... Dos

Part TU) 1894.%.2.00 10 10) e9 eee ame Part IV. 1905..... 010 0 .... 0

Part TV. 1806. 4.2 1 0 VS oeaa0 eo Part V,/1906. .... 0 7 (6 ieeaae

2nd Ser, ZOOLOGY. | (VOL. X. PART 6.

THE

TRANSACTIONS

THE LINNEAN SOCIETY OF LONDON.

BISCAYAN PLANKTON COLLECTED DURING A GRUISE OF

H.M.S. ‘RESEARCH, 1900.

Part VIII—THE CEPHALOPODA.

By Dr. W. E. Hoyts, Director of the Manchester Museum.

(Communicated by Dr. G. H. Fowter, F.L.S.)

Part IX.—THE MEDUS&.

By E. T. Browne, B.A., Zoological Research Laboratory, Univ. Coll., Lond.

(Communicated by Dr. G. H. Fowrerr, F.L.S.)

With a Note on the Distribution of the Medusze by G. H. Fowuer, F.L.S.

he Oe DH, :

PRINTED FOR THE LINNEAN SOCIETY

BY TAYLOR AND FRANCIS, RED LION COURT, FLEET STREET.

SOLD AT THE SOCIETY'S APARTMENTS, BURLINGTON-HOUSE, PICCADILLY, W.;

AND BY LONGMANS, GREEN, AND CO., PATERNOSTER-ROW,

October 1906.

LINNEAN SOCIETY OF LONDON,

MEMORANDA CONCERNING TRANSACTIONS.

The First Series of the Transactions, containing both Botanical and Zoological contributions, has been completed

in 30 Vols., and a few entire sets are still for sale. Only certain single volumes, or parts to complete sets, may be

obtained at the original prices. The price of the Index to Vols. 1-25 is 8s. to the public, and 6s. to Fellows; to

Vols. 26-30, 4s. to the public, and 3s. to Fellows.

The Second Series of the Transactions is divided into Zoological and Botanical sections.

{ The prices of the

Zoological parts of those which have been published are as undermentioned :—

Srconp Serres.— Zoonoey, Srconp Srrtns.—Zooroey (continued). }

When Price to the Price to When Price to the Price to

Volume. Published. Public. Fellows. Volume. Published. Public, Fellows.

ca os LdetS eC: fis! ide £ es de

I. Parts I.-VIII. 1875-79. 810 0....6 7 6 VI. Part Vie wsoG..... 0 80.22.80, eum

Il. Part. L870. le Oe emo aeenO, Part VII. 1896. .... 012 0....0 9 0

Part Tieeassie Ot O ..-. ®lm @ Part V Gees oiion 2... 0 2 622... 02a

Part Ul. 18G2ne ae L802 1 0!) VTS Part elooeee-.. 0 10° 0°. 2 Ona

Pant. 0 DV 91882:-. 6.2200 07,0 Ose Onto RG Part TL 1s97...... 0 12. 0 2 0uoman

Part @) Vil 883; on 10 0) eee e0 ibeO Part TV.i898).... 010 0 ....°0l) jame

Part. VU 1883. 5.0 > Oe Ome Ss 9 Part « “VW. g698..... 018 0 ..),-0) femme

Part WI 1883; ao. Oin3ei0 Se NO aes Part VI. 1898. .... 013 0)..<- O- gmee

Partoe Xs lSeS: 2 “eOUNS 0 eo ROR ens Part VIE0(S99.... 018 O50 Smee

Part) Xe S84 n2 00 4 Oe 0 eee Part VIII. 1899. .... 012 0.... 0 mm

Part XI. 1884..... OGLO; (0% 0M 6 Part IX. 9889)....1 0 0 ..2)) Osea

Pant: OXTE W885) 2.05.0" 6. Ol ssee UL E48 26 Part X,99005.... 0 6 0%,5.2) Oem

Parti Xe 18840 ct, 0". 6) a0 Olen G Part XI a900.0....0 2 9 .. 50a

Letty ROWE Wskehs Gooo Wa) (We ceoo WG) 8) Part DEe900ses.. 0 10 0) eee OueramG

Teh MOVIN IEE Sane (ich OW) sang UW) BP Part LVodG0leess. 0 14 (0) eeROMmlOMEG

Lem RVINL, Wists ao55 WO B® cuea th B Part “VielGoieee 0 5 0 220s ea

Ill. Part I URES goon Ul TE O case OH Part Vi. 1900S. - QMO sooo) 7 &

de NG WE oe LO O ssen tw Part VIL JO0Ieg! 8S 0 ~ ce iia

ene TOS aU os WD O s.5, 1 2 G6 Part VIIL) 19025e-. 0 4 0 .... 0 amo

Part A, we oe OY Sf On. O CB O Part. XX: 1903skere Wl 0: 0 1.6.) ORlaaG

Part.) WI 1S88.0 4.0006 1 450 OmeeeG Part “XI 19035508,0..6 0 ...270 gee

IV. Part | ‘1. Te@6h Lee a0. 2) eo alamo Part XII. 1903.2... 010 0....0 7 6

Page LT ASS7oR a8 10) en EO. Part XU indexer nO) 2) 29 0 eee

Part IIT. 1888..... 016 0'.... 012 0} “1% Part I. 100s 0 9 0... 0 ome

V¥. Part (x [os1688) 0. 2h0 120m a0. gronnO Port Oe ee

Part TE 19Reh Ment aee (0%. LOG Part Tk d903eee 1 4° 0.02. ORSaae

Part. JIT, 1880.0 70 ons deo Fat eee o.oo an

Part IV. 1890: ..2.2 0 leo aroun m0 Parts Vs eet? (6 30 ae

Park VEASOL Gouri eater Part, VII. 19045 4,3..0° 60>... ..0)heag

Part’ VIL. (8011.4, pi leateeene Part VIII. 1904, .... 0:10" 0 52. acu

Part VIII. 1892. .... 0: SOs enoeae 0 See ae eames

Part IX. 1892..... 0 12410) e010 et ee Oe

Pert =X. 1893.....1 8 0....1 1 0 K.. Part Se t004, kk OVS ROO eee

Bart > 2X. S94. ee Oe Geen Ome) Parh. De 1904... 2910) 8 Ome ORO

VI. Part I. 1894. 20 (0 £2 aleoeO Part III. 1905.....0 9 0....0 6 9

Part II. 1894, SON eal ae ees Part. IV. 1905.-.... 0°10 O%s2..,.0) Yi

Part III. 1894. 0.10: COTES 0m aap Part V.'1906; .. <0) * 7. Gate Oo

Part » LV. 1896,.,./, Li VO Ol see Part. VI.>1906. %+.. 075920". Oe

Part. ¥.-1896.. 222.2010) (0.0 0s ene

2nd Ser. ZOOLOGY. | (VOL. X. PART 7.

THE

TRANSACTIONS Km

OF A

BISCAYAN PLANKTON COLLECTED DURING A CRUISE OF

H.M.S. “RESEARCH, 1900.

Part X—THE FISHES.

E. W. L. HOLT ann L. W. BYRNE.

(Communicated by Dr. G. 11. Fowrrr, F.L.S.)

~ = .

hh Nae = i

ASAE

a 2

Sy; $ My ry)

Pia

= Nib

A eA | i

NY MONO SRT

oA.

y 3

MN,

Te ND OLN:

PRINTED FOR THE LINNEAN SOCIETY

RY TAYLOR AND FRANCIS, RED LION COURT, FLEET STREFT.

SOLD Al THE SOCIETY’S APARTMENTS, BURLINGTON-HOUSE, PICCADILLY, W.,

AND BY LONGMANS, GREEN, AND CO., PATERNOSTER-ROW.

May 1907.

LINNEAN SOCIETY “OF ON DOM

MEMORANDA CONCERNING TRANSACTIONS.

The First Series of the Transactions, containing both Botanical and Zoological contributions, has been completed

in 80 Vols., and a few entire sets are still for sale. Only certain single volumes, or parts to complete sets, may be

obtained at the original prices. The price of the Index to Vols. 1-25 is 8s. to the public, and 6s. to Fellows; to

Vols. 26-30, 4s. to the public, and 3s. to Fellows.

The Second Series of the Transactions is divided into Zoological and Botanical sections. The prices of the

Zoological parts of those which haye been published are as undermentioned :—

Srconp Srrims.— ZooLoey, Srconp Surres._—Zoonoey (continued).

When Price to the Price to When Price to the Price to

Volume. abheveds Public: Halloran ae: Published. Public. Fellows.

ae Pr eh onisa acl Lf ie id £ Jsnee

I. Parts I.-VIII. 1875-79. 8 10 0 6 7 6| VIEL Port “Teg800. .... 0 10 10) 2. eee

II. "Parts 1. XVELLS7O=88.07 ele Ose Deere] Part) I. 1200. .... 010 0 ..-.10) gaa

TU Part | /eh ect eee tb ee Tort TD: .. 0 100

Pack ee ae ae Hebe Part IV. 1901. .:.. 0 14 0° 2... OMtomme

| Part Vew900t,... 0 5 OS. 0 ome

Part. TM edses*.2 a: 110 0 Le 26) ‘ 4 : a

Part TVOHSBs. 0 80 ean | Part VE aor tees O10 SOR See ee ener

es Part VILag0ies... 1 8 Of). en

Part. ManV Seva 0S IIAP aCe 0) eee

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| Part 1X. 4902) 4... 0 5 0.0m

IV. Part TSeG ee Lae OL LOR Ley Part Xo 1908.... 1 0 0 .... OneimE

ie 0G, WEG sees I och Orsane i 1 Oy Part XT 1902..... 0 6 0 ....0) ae

Part IO, 1888. eienene 0 16 0 . . 0 12 0 Part MOE, 1908. a 0 10 0 ; ; 0 7 6

Port: IL, 1888. ..2. 0 5 O...5 0 3° 9) IX Part “egies 0 9 (Oen eOmCee

Part IV. 1890.....012 0....6 9 0| Port TU. 100je.. 1 4 0 . 2 osOReeme

Dartoe, Vo IS90:lee.c 10) M6N 10, 2 eeu0 adeno?) Part IV! 1904... 0 6 0 .... Oneene

Part WAR aisle, Cores (UT Oso 52 0) U8 0) Part V. [903 (0: 66: 0! = Oma

Part’ Vio 1801, ae <0n 6 s0r ee ele to Part: Vi. 1904. 0 6 0 ...070ueeme

Part VILI. 1892. .... Os Em) 0.2.40 0576" 40) Part VIL. 19042... 0 6 0.7... 0 4%

Punt! 9 ik GOD ee Ov12 760) pam 0G9e 10) Part VILL. 190495... 010 0 ....10 7am

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Part Dwi a ee 0) DERG se eee 0) Part xX” [90Geeee Olde oO) . 0 2oae

VI. Part TAS944 82.0 80>... al ON Oy) Part XI. 1907. e012 0 1; oe

i pn Progress.

a Se a Bs ae : oi 3 : : X. Part “1904.0. 3. 0... Oe )

Part IV. 189¢,....1 4 0 .... 018 0 gees °° Re |

Bank ve tena ee ean Part. TIl. 1905eyea8s0 99. 0.2.2 0 Gee

ae Part IV. 1905;ee-40 10. 0 ...2 0) foam

Part VII. 1896. vee OIRO. 5 0 Ome Park WS 3c) ae

Part VELL.o1S9 7a tO eo eae | m0 eee Part VET TUGRMILO. 30 nc

VII. Part. 1, 1896022..) 001030 07 % (In Progress.)

Part IL 1897... (0187 0.4.5.0 9 Ol

Part “Ill, 18075 =. 80m t6aOue 0 4 6

ride dO West oo 5. MO WO sias O 7 GB)

Part V. 1898)... 0189 Omeewauale. 6

Part VI. 1898.....013 0 09 9 -

Part VII. 1899.....018 0. 013 6|

Part VIII. 1899... 40 19) Ose ee Ommomncn

Part” “TXs 189924) J) 10 WO em oe

Part.’ VX: 1900: : 23/0960: wee Ome

Part “KI; 1900) s.9 30" De Op eeROMenO

2nd Ser. ZOOLOGY.) L[VOL. X. PART 8.

THE

TRANSACTIONS

THE LINNEAN SOCIETY OF LONDON,

BISCAYAN PLANKTON COLLECTED DURING A CRUISE OF

H.M.S, “RESEARCH, 1900.

Part XI—DECAPODA.

STANLEY W. KEMP, B.A.

(Communicated, with a Note on their Distribution, by G. H. Fowirr, B.A., Ph.D., F.L.S., F.Z.S.)

PONDON:

PRINTED FOR THE LINNEAN SOCIETY

BY TAYLOR AND FRANCIS, RED LION COURT, FLEET STREET.

SOLD AT THE SOCIETY’S APARTMENTS, BURLINGTON-HOUSE, PICCADILLY, W.,

AND BY LONGMANS, GREEN, AND CO., PATERNOSTER-ROW.

October 1907.

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LINNEAN SOCIETY OF LONDON.

MEMORANDA CONCERNING TRANSACTIONS.

The First Series of the Transactions, containing both Betanical and Zoological contributions, has been completed

in 30 Vols., and a few entire sets are still for sale. Only certain single volumes, or parts to complete sets, may be

obtained at the original prices. The price of the Index to Vols. 1-25 is 8s. to the public, and 6s. to Fellows; to

Vols. 26-30, 4s. to the public, and 3s. to Fellows.

The Second Series of the Transactions is divided into Zoological and Botanical sections. The prices of the

Zoological parts of those which have been published are as undermentioned :—

Srconp Serres.— Zooroey, Srconp Srrtus.—Zoonoey (continued).

When Price to the Price to When Price to the Price to

Golam: Published. Publie. Fellows. | Volume. Published. Public. Fellows.

fis a aS ead. £3. a £ shalt

I. Parts I.—VIIL. 1873=79: & 10 0 2 6) a 63) Nib Part TL. WO00me. =. 0 10 -:0° Se. 0 vane

II. Parts I._XVIII.1879-88. 7 17 0 5B 5 Pert If. 1900.....010 0....0 7 6

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Part De S84ieee. Jee ae luge: Part V. Fe. ae. Fe uo he a 0 Bue

ebay JUN iketsss 4455 Jf a0) (0) ele 2 AG) Part VE 1901, Sea ote Prins 0 aE

Part Weel S85: OV3r0 = OF 76550 Part VIL. coud ot + ee oe ee

Part MWe ctv Gane) teh -0 6 0 Part VIL. age an <a ae jee

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iV. Part, 1.W1866. Sow le ee 0 LE a0 Pot X. 1900 «0 0)... ORISman

rt Gt ERE ce BS kU Part XI. 1908geee2 0 6 0.10. 0 Ame

Patt et eS ele OF A ee Part XI. 1908...1.010 0....0 7 6

V. Part TeRUSES: ee Oma nO. 4) YF O Part XT. Indexsyeeen0) 2 9 .- SON

Part ML S88. 2.24 102 5210 Peay) IX. Part T. 1903) 0 9 0... ONG

Part eI S89.0 eel 70 5 ie Oe @ Part 1 1903 eon S 0 a OMNGREO

Part DV 8905 Oto 0 5 0) Part. Li LOSS: od 0 Cee OMI SmmO

Part V. 1890.....0 6 0....0 4 6 Part IV. 19040qeee0 6 0 .... OG

Part) avileliSOdeee ONL sO 22073910 Part Vo 1004.) G6. 0) OG

Part) Wie S92 wee. Oe tsh Ul naom OMe ipe Part Vil, 1904, 9enl0n 6 0 .-)-n0NreerG

Part IX. 1892.....012 0....0 9 0 Part VIII. 1904.....010 0....0 7 6

Part: (9X. a803. 000.57 98 70.2. Pd 0 Part IX. 1905.ccee0. 6.0 |... OUR

Part aeeeo452- 10) 2 56 410) 2104 Part X. 1906 -eeeROwlo (0... 90 OMG

VI. Part Tea SO4. ce nO nO ae 1 OR) Part’ XI, (19072 232eOw2 0....¢ 0 ae

Part HiT O4. 7 5.) Lgl a0 Ik a}. 3} Part XT. 190 (aoe, 0). eee

Part “Ti Weo4s 0 10) 0 Oo 6 Part XDI, 19075 ce 6= 0 22. 10. AG

Part) SVE SOC eer ieleeO 0 1850 Part XIV. In the press.

Part AY isias s4a5 (0) ko Ww sO Ff @ X. Part T, 19045 pOees OF. 2. TOM eas

Pach Wi so6 ee OmomnO 59 8 Part 1. 190430” 8 0! pe O GeaD

Part ‘VillseeOGsene. 012 0 5 fy 2) Part’. DUT, 2905 nega 0 70° ve emO Gao

Part. VL 1897. 5... 0) 42.96 Oe ee a0 Part IV. 1905..... 010 0 - 10 7s

VII. Part I. 1896..... 040. bes. 0 ¥a8 Part ‘V. 1906.e., 0° 7 36 2.2 ome

Part 0. 1897..... 0.12 0 Sy Part. Vi. w90Ghey.. 10) {3 30 RR 0 ae

Part “Til. 1897.,..<,, 0) 6 Osees a0) eo Part ‘VIL. 10074... 0° 73 BDCee EO an

Park GLVe 18989650 LOMO 5 8 PartVill W290seen.. Ota 4041340

Part ~ V,1898..,.. 01480 018 6| — cee

Part VI. 1898..... 018 0 pope XL Part. “Ti 907F ee... 1S Oe el ee

Part VII. 1899. -..2. 0 a8 70 ; OWSEIG

Part VIII. 1899..... 012 0 . 0 9° 70

Part 1X. 1899. .... 1°10 70) “e015 30

Part KX, 900.8 222.10 296 SOM ere eee tO

Part’ <Xi-1900.7%... 0. Bin a0 Omen

2nd Ser, ZOOLOGY. | LVOL. X. PART 9.

THE

AE\CA Pas

S55°° 7

TRANSACTIONS Gen

zs Sf

OF . La R, Y A

THE LINNEAN SOCIETY OF LONDON.

BISCAYAN PLANKTON COLLECTED DURING A CRUISE OF

H.M.S. ‘RESEARCH,’ 1900.

Part XII—THE OSTRACODA.

G. H. FOWLER, B.A, PaD., F.LS., F.ZS.

GO N D@N:

PRINTED FOR THE LINNEAN SOCIETY

BY TAYLOR AND FRANCIS, RED LION COURT, FLEET STREET.

SOLD AT THE SOCIETY’S APARTMENTS, BURLINGTON-HOUSE, PICCADILLY, W.,

AND BY LONGMANS, GREEN, AND CO., PATERNOSTER-ROW.

November 1909.

’

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/ LINNEAN SOCIETY OF LONDON.

MEMORANDA CONCERNING TRANSACTIONS. +t

Y r,

The First Series of the Transactions, containing both Betanical and Zoological contributions, has been completed

in 30 Vols., and a few entire sets are still for sale. Only certain single volumes, or parts to complete sets, may Ber

obtained at the original prices. The price of the Index to Vols. 1-25 is 8s. to the public, and 6s, to Fellows; to

Vols. 26-30, 4s. to the public, and 3s. to Fellows. : “i

The Second Series of the Transactions is divided into Zoological and Botanical sections. The sia 0

Zoological parts of those which have been published are as undermentioned :— ‘

Srconp Srrres.— ZooLoey. Srconp Srrtns.—Zooroey (continued).

When Price to the Price to WI Price to th

Volume. Published. Public. Fellows. Vohone: Published. "Public. ;

a SC EG Se) 1Cyl e Lends

I. Parts I-VIII. 1875-79.8 10 0.... 6 7 6| VIII. Part XII. 1903..... 0-10 0.

Part XII, Index. .. ;

Il. ParteI.-XVIII.1879-88. 717 0.... 518 5 ; pork, + Oa

IX. Part) Gos)... 0 Bi Ges

III. Parts I-VI. 1884-88.. 518 0....4 8 6 Me ae

IV, Parte i.—U01, 1886-86.. 3 8.10 2... 211. 0 Part II. 1903.....1 4 0.

Part D004. .... 0 610.

V. Parts I.-XI. 1888-94..610 6 4.17 9 Party aveelOOds .... 0) sGmROUs

Wis Part" Te leeds 2). -9° 0) 0 A io ae cae 6 Oe

Pactae A dBbd, «2. Waal 04 eo koht aes ee | ae Come

Pai’ TM WADA. wy. G10 0-2 ee ae : oe ee

Part VI. 1896. ...,.0 8° 0 2... 06-0 ac) ama 0 wee

Part VI 1806. 2).. O12 0 arg ou cee a ps 0) Sa

Part VIIL. 1897.....0 2 6 ...,0 2 0 are 8

Part XIV. 1907.Index.0 3 0.

VII. Part I. 1896..... 010 0.4 OO 8) Seg ee

Part. - 10). 1697;....010, 12. 0%.,..00 (9 "0 if

Part II. 1904.....0 8 0

Patt. TEL, Ue0ycca. 0 6 -0-.)y.206 ne Pat SS (aa

Part TV. 1808,c¢., 010 0 :.2..0 7 26 ps 5 ae ;

Part IV. 1905.....010 0.

Part. Vi 18982... ¢..0 18) O14, 0 1806 Post cee

Part) (Wie 1808.¢7;..018 0°...:°0) 9° 9 Part HM. 3008

Part Will. 1899. .a,4 0018 “0.1. 1..0-0ame rd

Part VIL. 1907.....0 3 0.

Part VIII. 1899. .... 0 12 6... 0°98 90 ee

PartVIII. 1907.....0 4 0.

Park | DE; 1808) Ae 1 00 OO Pace’ ai ae

Part X,)1900.b£ 06 0.2. OVEG ~ (in progress.) |

Part XagOOOMNEE TO, 2 00... 0 ) 20a See ieee... 4 we

WAT, Bart’ “I, W000) 52. 0:10) 0... Was Part IL. 1909.....0 8 0.

Part Ti; 1000....4.10/10 0... 0 6 Part I. 1909.....0 6 0.

-Part WT, 1900553.) a0. 0.7.5 OamimG Part IV, 1909. .... 0 12 0

Part IV. 1901.....014 0....010 6 Part V. 1909. .... 0 2 0

Part -V. 1901 0 5 One 0 Bie ies 5 ae Ree

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Part ‘VII. 1001, '.:..' 1 8) Oey ae Pe ee tM eis

Part VIII. 1902.....0 4 0....0 3 0 weer Ba oa

Part IV. 1909. ....

Part IX. 1902..... 0° 6, 0: 1s ameense tik Se. y900 EO

Part X. 1908.c%.. 1 0 O°... 0gle@ Te Oc A aig

Pert XI. 1908.....0 6 0.... 0 4 6| M&UM Part 1. 1800),

Ae Ces Seen Hp eee pe PY ef - see Vier ees * a

[VORAX. PART 10.

TRANSACTIONS

BISCAYAN PLANKTON COLLECTED DURING A CRUISE OF

“ HAMS. “RESEARCH,’ 1900.

Part XIII.—THE SIPHONOPHORA.

ak a a PICCADILLY, Ww, . -_ i

MEY NE es ORS n wh

NS, GREENS “AND! (O., PATERNOSTER-ROW.

2nd Ser. ZOOLOGY. | (VOL. X. PART 11.

THE

TRANSACTIONS

THE LINNEAN SOCLETY OF LONDON.

TITLEPAGE, CONTENTS, AND INDEX.

Mas?

ee)

L.O-N D ON:

PRINTED FOR THE LINNEAN SOCIETY

BY TAYLOR AND FRANCIS, RED LION COURT, FLEET STREET,

SOLD AT THE SOCIETY'S APARTMENTS, BURLINGTON-HOUSE, PICCADILLY, W. al

AND BY LONGMANS, GREEN, AND CO., PATERNOSTER-ROW.

June 1922.

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LINNEAN SOCIETY. OF LONDON

MEMORANDA CONCERNING TRANSACTIONS.

The First Series of the ‘Transactions, containing both Botanical and Zoological contributions, has been completed

in 30 Vols., and a few entire sets are still for sale. Only certain single volumes, or parts to complete sets, may be

obtained at the original prices. ‘lhe price of the Index to Vols. 1-25 is 8s. to the public, and 6s. to Fellows; to

Vols. 26-30, 4s. tio the public, and 3s. to Fellows.

The Second Series of the ransactions is divided into Zoological and Botanical sections. he prices of the

Zoological parts of those which have been published are as undermentioned :—

Second SmriEs.— Zoonoey. | Srconp Srrims.—Zoonoey (continued).

When Price to the Price to

Volume renee repee j “a rele When Price to the Price to

Published. z ublic. Fellows. Volume. Published. Public: Fellows.

Ce te ae Gees: d. | fs ;

Pri [ely 75270) 2 Ta ee ioaenG bea as

I. Rants — Valeo non ccmlOne Ome se Gn ll spar eC ee ee

II. Parts ._XVIII.1879-88.7 17 0 .... 518 5| Part I. 19074... 1. 0.» aeoaieaen

| Part IL. 1908s -. . )

III. Parts I-VI. 1884-88.. 518 @...4 8 6] pt. Tee OES 0 Oren

| Part LV. 1909s... 110: 10'S ael eee

IV: Parte -1T. 1886-68 . 3 8 0 coe DL On Part V. 1909.Index.0 5 0 0 379

VI. Parts].-VIII. 1894-97. 617 6....5 3 8 Pag TI. LOUss 2° 3 0 .sieh Dee ee

Part. Til, 19V0see0 16 0 Seeeomnomen

Es, ee eh eer & 2

VII. Bo Ae tla 2 Ie G7) Oe eel a9 Part IV. 1910) Imues"0 5 0 ....00) uae

VIE. Phrts HREM, 1900L0Se7 ath Olle hear

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IX. Parts 1—XIV. 1903-07.5 17 0... 4 7 9 Put Uli zoeet. 0 05, Sarimigesg

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Part 12100) 0,680. «400 Len wD BRE DY he ey ae. «Ooo OMe

Part TE POOR ee BE es OOO) ve Part) 1 ee.

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ee 7 C + 7 4 S 5

Pets i: Va ee GN ae Part II, 1912. =". eNO es. OuldamG

D Prt 7 € > 3 2) «

Pani Vil OU see ee Name. aots. Uieee, Re Phit EX. 1913 %dexsOe2 0). 0 9

Part «Vill VOOR. 2. 4.410 omen OF De SH r

Part. VIEL. 1907. 9s:. 0 4:0 .. . 0 3) 0) xevik Parba tors. Sei 0-22: 0 ee

Part: 1X. 19005.) og Glin. OS 0) Party aU Ko1Sy ce alee ON. 2 2OmI5) 29

Bart, 7” Xe SIS em) ea) 0 3 Part III. 1913. .:.. ®) 1Qeee SROF 910

Part XI. 1922.Index.0 3 0 2 O “2.8 Part IV. 1912¢a.01 100” 2 eee

: ; Purt V;1914.Index.0 3 0 a Bs

MS Bart Le. NODS 4. 10) GAR Ue 520 eres r

Part IT. 1909. :... 0° 8 0°...: 0 6° OO pare PLAST 2 0 One 1100 a0

Part WT: “1909.5 eres (ORG ser O eres WO aetna) Park I WONG. kh 3° ON, O17 3

Part IV) 1909. ..:. Oe OL... 22 0. me Park: Lola eNO 018 9

Part V. L909. e220 210. ee Os Gs Tart V0 WOOlbeaee (Ont tOne 039.0

Part VI. 1910..4.70,11 0 5... Omeaeeet

(Index in preparation.)