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THE

TEANSACTIONS

or

THE LINNEAN SOCIETY

OF

LONDON.

SECOND SERIES.— VOLUME XIII.

ZOOLOGY.

THE PEECY SLADEN TRUST EXPEDITION

TO

THE INDIAN OCEAN IN 1905,

UNDER THE LEADERSHIP OF

Mr. J. STANLEY GARDINER, M. A, Vol. II.

LONDON:

PHINTED BY TAYLOR AND FRANCIS, RED LION COnitT, FLEET aTitEET -.

SOLD AT THE SOCIETY'S APARTMENTS, BURLINGTON HOUSE ; AND BY LONGMANS, GREEN, AND CO., PATERNOSTER-ROW.

1909-1910.

REPORTS

OF THE

PERCY SLADEN TRUST EXPEDITION

TO

THE INDIAN OCEAN IN 190o,

UNDER THE LEADERSHIP OF

Mr. J. STANLEY GARDINER, M.A.

VOLUME THE SECOND.

[BEING THE THIRTEENTH VOLUME CF THE SECOND SERIES, ZOOLOGY, OF THE TRANSACTIONS OF THE LINNEAN SOCIETY OF LONDON.]

LONDON:

PKISrrED BY TAYLOK AND FEANCIS, RED LION COURT, FLEE! STKEFT :

SOLD AT THE SOCIETY'S APARTMENTS, BURLINGTON HOUSE ; AND BY LONGMANS, GREEN, AND CO., PATERNOSTER-ROW.

1909-1910.

CONTENTS.

PAUT I.— October, 1909.

I. On some Nemerteans from the Eastern Indian Ocean. By R. C. Punnett, M.A., and C. Forstee, Cooper, 3I.A. (Comnumicated by J. Stanley Gardiner, M.A., F.L.S.) (Plates 1 & 2.) pages 1-15

II. Beiwrt on the Echinoderma {other than Molothnrians) collected hy Mr. J. Stanley Gardiner in the Western Farts of the Indian Ocean. By P. Jeffrey Bell, M.A., Emeritus Professor and Fellow of Kincjs College, University of London. {Communicated by J. Stanley Gardiner, M.A., F.B.S., F.L.S.) (Plates.) 17-22

III. Etude des Clrripedes de V Ocean Indien. Far A. Gruvel. {Communique par M. J. Stanley Gardiner, M.A., F.B.S., F.L.S.) 23-27

IV. ' Sealark' Bhynchota. By Wm. Lucas Distant, J'. ii'. 5'. {Communicated by J. Stanley Gardiner, 3I.A., F.B.S., F.L.S.) (Plate 4.) 29-i7

V. Amphipoda Ryperiidea of the ' Sealark ' Expedition to the Indian Ocean. By A^.TREJ) O.Walker, F.L.S., F.ZS 49-55

VI. The Land and Freshwater 3Iollmca of the Seychelles Archipelago. By E. E. Sykes, B.A., F.L.S. (With 3 Text-figures.) 57-64

VII. Beport on the Marine Mollusca obtained by Mr. J. Stanley Gardiner, F.B.S., atnong the Islands of the Indian Ocean in 190o. By James Cosmo Melvill, M.A., L.Sc, F.L.S. (Plate 5.) 65-138

32546

[ vi ]

PAET II.— February, 1910.

VIII. Alcijonarknis collected on the Fercy Sladen Trust Expedition hy Mr. J. Stanley Gardiner, M.A., F.H.S.

Part I. The Aa-ifcra. By Prof. J. Arthur Thomson, M.A., and W. E. Russell, M.A.

Part II. The Stolonifera, Alcyonacea, Pseudaxonia, and Stelechutukea. By Prof. J.

Akthcii Thomson', M.A., and Miss Doiiis L. Mackinnon, B.Sc, Carnegie

Schul/ir, Uiih'ersUy of Aberdeen.

(C'onmmnicated by J. Stanley Gardiner, 31. A., F.E S., F.L.S.) (Plates 6-14.) pages 139-211

IX. The Cephalochorda: " Amphioxideis." Fy U.O. ^. GiBSOii, F.A., Kew Colleye, Oxford. {Communirated by J. Stanley Gardiner, 31. A, F.B.S , F.L.S.) (Plate 15 aud 1 Text-figures.) 213-25G

X. Fen^idca, Sleno'pidea. and Feptontia from the TFestcrn Indian Ocean. By L. A. BoRRADAiLE, 3I.A., Lecturer in Natural Sciences at Selwyn College, Cambridye. {Communicated by J. Stanley Gardiner, 3I.A., F.B.S. , F.L.S.) (Plate 16.) 257-2G4

XI. Lepidoptera, exclusive of the Tortricidae and Tiueidae, tcith some Remarks on their Distribution and 3Ieans of Dispersal amongst the Islands of the Indian Ocean. By T. Bainbrtgge Fletcher, R.N., F.L.S. ( Communicated by J. Stanley Gardiner, 3I.A., F.E.S., F.L.S.) (Plate 17.) .... 2G5-321

XII. Polychcefa of the Indian Ocean. Part II. The Palmyridae, Aphroditidae, PolynoiduR, Acoetidse, and Signalionidse. By F. A. Potts, 3I.A., Fellow of Trinity Hall. Cambridge, and Demonstrator of Comparative Anatomy in the 'University of Cambridge. {Connnunicafed by J. Stanley Gardiner, 31. A., F.B.S., F.L.S.) (Plates 18-21.) 32-3-353

PAET III.— June, 1910.

XIII. On the Dep)t]b and Marine Deposits of the Indian Ocean, luitk Descriptions of the Deposit-Samples collected by Mr. J. Stanley Gardiner in 1905. By Sir John Murray, K.C.B., D.Sc. F.B.S., F.L.S., ^-c. (Plates 22-24.)

355-39G

XIV. The Orneodidw and Fterophoridcc of the Seychelles Expedition. By T. Bainbrigge Fletcher, B.N., F.E.S. {Communicated by Prjf. J.Stanley Gardiner, 3I.A., F.B.S. , F.L.S.) (With 1 Text-figures.) .... 397-404

[ vii ]

XV. On the Land and Amphibious Decapoda of Aklabra.

31. A., Ij(^ctu)-er in Zoology in tlie TJnicersily and at Selw>/h [Communicated tiij Prof. J. Stanley Gauuinee, M.A., F.R.S., F.L.S.]

By L. A. EoiuiABAU.i;, Xj Dj/n Collegp, Cambri.dt/e.-^^'/[

]^VI. Nudibranchs collected hy 3Ir. Stanley Gardiner from the Indian Ocean in K.M.S. ' Sealark: By Sir Charles N. E. Eliot. K.C.M.G.. C.B. {Communicated by ProP. J. Stanley Gardiner, M.A., Fli.S., F.L.S.) (Plate 25.) 411-4;^s

XVII. JReport on the Brachiopoda obtained from the Indian Ocean hy the ' Scalark' Expedition, 1905. By William Healy Dall, A.M., Sc.I) , Cure for Die. IIoll. U.S. Nat. litis. {Communicated by Prof. J. Stanlev Gaimhner, M.A., F.B.S., F.L.S.) 43!)-4'il

PART IV.— November, 3910. Tittepages, Contents, and Index 'l-13-i7>i

EERATA.

Page 13, line 12 from top,/b/- Cerebratiilus stecnerii read C. steineni, Bliiyer. ,, 13, line 13 from top, /o/' 0. pochohoutas read C. pooohontas, Girard.

15, line 5 from top, for Ccrcbratidus crosslaadi, sp. n., read Lineus crosslnndi, sp. u. (see page 0). 71, lines 1 and 2 from bottom, for Scabricola read Scabricula. 71, lines 8, 9, 10 from top, for Coralliophora read CoralUophila (see page 105).

,, 164, line 1 from top, for Scirpearia Jiabdlam read S.JIayeUum, Johnson.

262, line 6 from bottom, for Calliande read Calliadne.

310, line 17 from bottom, for Pachyzmula phceopteralis read P. ph<eoptendk, Hampson.

315, lines 20 and 21 from bottom, for Ateila read Atella.

430, line 7 from bottom [Chromodoris Utiearis],

TRANSACTIONS OF THE LINNEAN SOCIETY.

THE PERCY SLADEN TRUST EXPEDITION

TO

THE INDIAN OCEAN IN 1905,

UNDER THE LEADERSHIP OF

Mr. J. STANLEY GARDINER.

VOLUME II.

No. I. -ON SOME NEMERTEANS EROM THE EASTERN INDIAN OCEAN.

By R. C. PuNNETT, 31. A., and C. Eorster Cooper, M.A.

(^Communicated by J. Stanley Gardiner, M.A., F.R.S., F.L.S.)

(Plates 1 & 2.)

Read 5th November, 1908.

Introduction.

In the following pages some account is given of 20 species of Nemerteans from the Eastern Indian Ocean. In addition to those collected by the Percy Sladen Expedition, we have been able to examine a collection made by Mr. Cyril Crossland at and near Zanzibar, and also a few procured by Professor Herdman fx-om Ceylon. To these two gentlemen we desire to express our thanks. Other specimens reached us besides those described below, but owing to their imperfect condition or to their unsatisfactory preservation we have not included them in our account. It is to be regretted that in no case were observations made on the colour of the living worm. We have endeavoured, so far as is possible, to remedy this defect by coloured drawings of the preserved material, though we realise that these are but a poor substitute for sketches from life.

Like that of many groups, the nomenclature of the Nemertea has suffered frequent vicissitudes during the recent priority quest, and once familiar genera are now disguised by unfamiliar terms. As we have accepted the system given by Burger in ' Das Tierreich' (1904) we have not considered it necessary to set out the literature and synonyms previous to 1900. Those who wish to ascertain why Carinella and Ettpolia have given place to Tubulanus and Baseodiscm will find in that indispensable volume reasons which are doubtless good.

SECOND SERIES. ZOOLOGY, VOL. XIII. 1

2 PERCY SLADEN TEUST EXPEDITION.

In a collection of Nemertea from any region the genera Lineus and Cerebratulus are sure to bulk largely, and the determination of the various species on preserved material is the most harassing part of the nemertinologist's task. For this reason we have collected together in the form of an Appendix the scattered observations dealing with anatomical points which we feel to be likely to prove of service. We trust that the recording of these points wiU commend itself to future observers, and that the numerous gaps in the table will become gradually filled.

But though the validity of a Lineid species may be established on its anatomy the systematist is yet confronted with the task of referring it to one of the three genera Lineus, Micrura, or Cerebratulus. In the days when comparatively few forms were known this was easy, but with the rapid increase in the family of the Lineidse it has become more and more difficult to frame definitions for these three genera. The absence of a caudicle has been relied on by most authors for the separation of the genus Lineus from the other two ; but a delicate structui-e like this is a most unsatisfactory feature to work with it is frequently missing in the living and almost always in the dead. Nor do we consider it to be a good generic criterion, apart from these practical difficulties. Its use in classification may unite forms which are widely difi"erent in other respects, and at the same time may relegate to different genera forms which differ in little else but the presence of a caudicle *.

In most zoological families it would appear that the constituent species fall into several groups, such that all the members of a given group are differentiated from the members of another group by several constant peculiarities, and these generic characters are held to differ from specific ones in their greater antiquity. It is not possible to point to any such grouping of characters among the Lineidte. Though there is considerable diversity of structure among the members of the family, and though the systematist has to deal with a number of characters, there is yet no association or gi-ouping of these characters to admit of our establishing genera with obvious claims to be considered natural. Nevertheless, the family already contains more than 150 species and for cataloguing purposes some form of subdivision seems to be called for. In the present paper we have referred to the genus Lineus such Lineidse as possess a gelatinous connective-tissue layer and to the genus Cerebratulus such as are without it. But in assigning a species to one genus or the other we have been guided purely by convenience, and we do not wish to imply that in our opinion there is any peculiar phylogenetic significance in the criterion which we have chosen.

To one further point we wish to call attention in this connection. Since future sy sterna tists will doubtless bring fresh ideas to the arrangement of this mass of species, we venture to suggest that in the naming of new forms care should be taken not to apply to a new species a name which has already been used for a member of any of the three genera in question.

* Thus Mkrura varicolor and Lineus ruber (olim guserensis) differ in little else than the possesaion of a caudicle by the former (Punnett, Bergons Mus. Aarbog, p. 21, 1903).

PUNNETT AND FOESTEE COOPEE NEMEETEANS. 3

Geographical distribution. The present collection is on the whole what our previous knowledge of the forms from the Indian Ocean might have led us to expect. The genera Drepanophorus and Baseodiscus together with the Lineidas are well represented, and there is also a species of Frosadenoporus. But the collection is remarkable for the presence of a Tubulanus a genus not hitherto recorded among any of the collections from the Indian Ocean. With the increase of our knowledge it is probable that other genera will turn out to be cosmopolitan. Of the present genera, however, one may be of some interest from the point of view of distribution. The records given in this paper

Distribution of Diplopleura.

make it clear that Diplopleura extends right across the Indian Ocean, finding its way eastwards to Japan and New Florida, and pushing up on the west into the Red Sea and the Mediterranean. It is a highly specialised form, and undoubtedly one of the most recent productions of the Lineid family. "We give a map of the distribution of this peculiar and striking genus, which is complete so far as is at present known. Its occurrence both in the Mediterranean and Indian Ocean may possibly be of significance for problems connected with the distribution of the marine fauna of these areas.

PERCY SLADEN TEUST EXPEDITION.

Description of the Species.

1. Tubulanus polymorphus (Renier, 1804). (Plate 1. fig. 8; Plate 2. fig. 12.)

Locality. Wasin, British East Africa (Crossland Coll.).

A single small specimen lacking the hind end. The colour after preservation is pale brown with a darker band 5 mm. wide, which begins about 3 mm. from the anterior end. The external appearance is very similar to that figured by Burger for T. polymorphus, and we are, on the whole, inclined to refer our specimen to this species while recognising the following small points of difference.

There are indications of a ventral muscle-cross in the ventral CESophageal region, which are, however, not well marked and disappear behind the level of the excretory pores. The diagonal muscles usually found in T. polymorphus between the longitudinal and circular layers are not present, but this possibly is due to the small size of the specimen. Again, the rhynchodaeal glands in this species are ventral, whilst in T. polymorphus, as figured by Burger (Naples Monograph, pi. xii. fig. 9), they are dorsal (PL 2. fig. 12).

2. Prosadenophorus buergeri (Punnett).

Literature. Punnett, R. C, Fauna & Geogr. Maid. & Lace. Arch. vol. i. pt. 1.

Locality. Wasin, British East Africa (Crossland Coll.).

A single specimen of this species was collected by Mr. Crossland. With the exception that the proboscis contains 21 instead of 19 nerves, this form closely agrees with that previously recorded from the Laccadives (Island of Minikoi).

3. Drepanophorus roseus (Punnett). (Plate 1. figs. 4«, 4 ft.) Literature. Punnett, R. C. Fauna & Geogr. Maid. & Lace. Arch. vol. i. pt. 1, p. 112.

Locality. He Diamant, Peros Banhos, Chagos. From a colony of Mussa, 15 fathoms, a single specimen measuring 40 mm. in length, 5 mm. in breadth.

Dorsal surface dark red, ventral pale yellow. The head is characterised by yellow markings (fig. 4 b). The small longitudinal head-furrows are conspicuous.

In internal structure this specimen agrees very closely with D. roseus from the Maldive Islands ; in fact, the only point of diflTerence is that the proboscis-nerves number 23 in this specimen against 22 recorded for the type specimen. It is in all probability a local colour-variety.

There is a point of interest in connection with the excretory system, in that the left duct passes round and over the outer side of the nerve-cord, while the right duct opens to the exterior by passing along the inner side of the nerve-cord in the usual way.

The large blood-corpuscles which were such a feature of the type specimen are also found here.

PUNNETT AND FOKSTER COOPER NEMERTEANS. 5

4. Drepanophorus indicus, sp. n. (Plate 2. figs. 13 a, 13 5, 13 c.)

Locality. Salomon, Chagos. A single specimen of this small species measuring 31 X 4 vam. The large proboscis was extruded.

Colour, when preserved in formalin, white without any trace of markings, though anteriorly there is a faintly pigmented appearance. Prom the medium used for preservation it may be inferred that the specimen was colourless, or nearly so, in life.

The chief diagnostic features of this species are the following : 9-10 pairs of eyes are present. There are 16 proboscis-nerves. The cerebral organ lies by the side of the brain and reaches posteriorly beyond it ; characteristic of this organ is a well-marked glandular extension which extends backwards for some considerable way just dorsal to the nerve-cord; this extension is not so long as that found in D. cerinus, and resembles more the condition found in D. willeyanws. The opening of the cerebral organ is lateral (PI. 2. fig. 13 a), the excretory pores are on the ventral surface close behind the brain.

The specimen is female, but immature, and no ducts are developed. The species has affinities with D. cerinus and D. willeyanus. From the former it differs in that the cerebral organ is not entirely behind the brain ; in the number of proboscis-nerves, 16 in this species against 14 in D. cerinus; and in the shorter glandular appendage to the cerebral organ. Prom the latter it differs in the absence of the chocolate markings which characterise that species as well as in the more anterior situation of the cerebral organ ; the intestinal region also in the present species is considerably more flattened than in J), tcilleyanus and the gut-diverticula are deeper.

5. Drepanophorus sp.

Locality. British East Africa.

Incomplete fragments of moderate size are referable possibly to D. latus or some closely allied form.

Numerous eyes ( > 30) are present, arranged in two groups on each side. The cerebral organ is lateral and reaches a few sections only behind the brain. The proboscis as well as the entire epithelium is missing.

Another specimen from the Seychelles, 37 fathoms, 18-5 mm. in length and 4 mm. in breadth, agrees in general features, as far as can be observed, with the above. It likewise lacked proboscis and epithelium.

6. Baseodiscus insignis, sp. n. (Plate 1. figs, la, lb.) Locality. Zanzibar, from muddy shore at low tide (Orossland Coll.).

A single specimen, 320 mm. long and 6'5 mm. broad. The extruded proboscis was 2 mm. in breadth.

The epithelium has been macerated off, rendering the pigmented pattern in the cutis very distinct. This pattern consists of a series of close longitudinal chocolate-brown stripes on the dorsal surface, the stripes on the ventral surface being further apart and rather broken up. There is a well-marked circular head-furrow.

Li I L I a

6 PEECY SLADEN TETJST EXPEDITION.

The epithelium, such as remains, rests on a fairly stout basement-membrane, immediately under which is the pigment. A thick layer of cutis-glands rests upon an equally thick gelatinous layer. The head-glands are well-developed and extend in the longitudinal muscle-layer as far behind the end of the mouth as this itself is behind the tip of the snout ; they are found ventrally as well as dorsally, aud in section appear as a broken ring in the outer longitudinal muscle-layer.

The circulatory system shows the cephalic lacuna characteristic of this genus.

The lateral nerve-cords are somewhat more ventral than is usual.

The state of preservation renders it impossible to deal satisfactorily with the excretory system.

The numerous eyes extend back as far as the brain-region.

The proboscis is two-layered and is without muscle-crosses.

7. Baseodiscus sordidus, sp. n. (Plate 1. fig. 9.)

Locality. Praslin, Seychelles, from the reef.

Length 200 mm., breadth in the oesophageal region 4 mm. Colour when preserved in spirit a dirty green.

The epithelium rests upon a distinct basement-membrane, under which occur circular and a few longitudinal muscles. The layer of cutis-glands is well marked, and is approximately the same thickness as the gelatinous layer. Both epithelium and cutis appear to contain some pigment.

In internal structure this species is of the usual Baseodiscus type. There are many excretory ducts on each side. The head-glands reach just past the cerebral organ and are dorsal only. The eyes are small and numerous.

8. Baseodiscus longissimus, sp. n.

Locality. Zanzibar (Crossland Coll.).

Several specimens of a very long white form, in general shape resembling B. hemprichii. The length of one complete specimen was over 800 mm., the breadth averages 3-4 mm.

The structural points which seem to separate this species from other members of the genus are as follows: The head-glands are well marked and stretch some distance behind the brain, where they lie in the longitudinal muscle-layer ; viewed in section they completely encircle the circular muscle-layer, but are most strongly developed dorsally and ventraUy. The proboscis-sheath is comparatively short, extending through not more than a quarter of the length of the worm. The proboscis itself is feebly developed, but contains both circular and longitudinal muscle-layers.

The exci'etory tubules are not connected by ducts passing to the exterior, such as usually occur in the group. There are, however, slender ducts which place the excretory system in communication with the gut *.

* A similar condition is known to occur in the following other members of the genus : B. quinquelineatus (Punnett, Q. J. M. S. sliv. 1000, p. 113), B. indicus (Punnett, Fauna & Geogr. Maid. & Lace. Arch. i. pt. 1, pp. 102, 104), B. civguhitus (Coe, liiol. Bull. 1906). In connection with the last species the author has gone into the question in some detail.

PUNNETT AND FOESTER COOPER NEMERTEANS, 7

Numerous small and degenerate eyes occur which are entirely destitute of pigment. The circular head-furrow is thrown up into a numher of short longitudinal ridges greatly resembling those described for B. indicus, Punnett (Fauna & Geogr. Maid. & Lace. Arch. i. pt. 1, p. 105).

9. Baseodiscus hemprichii (Ehrbg. 1831).

Localitij. Ooetivy I. Two specimens.

10. Linens albovittatus (Burger, 1890). (Plate 1. fig. 10 ; Plate 2. fig. 14.)

Literature. Burger, Zeit. f. wiss. Zool. 1890.

Punnett, R. C, Willey's Zool. Soc. Results, pt. v. 1900.

Proc. Zool. Soc. 1900.

Staub, Semon's Zool. Forscbungs. 1900. Punnett, R. C, Fauna & Geog. Maid. & Lace. Arch. pt. i.

Locality. Salomon, Chagos ; on reef.

A single much-contracted specimen 80 mm. long and 5"5 broad. Colour dark olive- green with characteristic zigzag yellowish-white band on head.

We refer this specimen to L. albovittatus, though it differs in one or two points from previous records.

The epithelium (PL 2. fig. 14) is high and rests upon an exceedingly thin base- ment-membrane ; the lower portion is closely packed with greenish glandular cells, to which the coloration of the animal is very largely due. There are distinct circular and longitudinal muscle-layers in the cutis, and the cutis-glands are separated from the outer longitudinal muscular layer by a sheet of gelatinous connective tissue which is thicker than the combined cutis and epithelium.

The vascular system, which contains a corpusculated fluid, has a well-marked head- loop. The rhynchocoelic vessel leaves the proboscis-sheath just behind the mouth- opening at the level where the nephridial tubules cease.

The excretory system is first found at the level of the middle mouth-region, and extends a short way behind its posterior limit ; the tubules do not extend ventrally below the nerve-cord, while dorsally they reach nearly to the rhynchocoel ; they open by a single pair of large ducts at the hinder limit of the mouth, the pores being situated laterally close above the nerve-cords.

In the brain the dorsal lobe of the dorsal ganglion is very large. The head-slits reach almost to the brain and are not prolonged behind the cerebral organ.

Numerous small eyes occur, mostly at the tip of the snout; a frontal organ is present, though not of the usual form, being single instead of trifid.

Another specimen in poor condition was obtained by Mr. Crossland from Wasin, Brit. E. Africa.

11. Linens mascarensis, sp. n. (Plate 2. fig. 15.)

Locality. Zanzibar (Crossland Coll.).

Several specimens of this small species were obtained. The colour after preservation

8 PERCY SLADEN TEUST EXPEDITION.

in spirit is a very pale yellowish white. The head is not marked off from the body, and the hind end is pointed ; a caudicle may have been present.

The epithelium (PL 2. fig. 15), which is high and packed with large unicellular glands, rests upon a thin basement-membrane. Beneath this there is a delicate cutis containing a few small gland-cells and some muscle- fibres. This cutis is considerably thinner than either the epithelium or the well-marked gelatinous layer on which it rests. The inner longitudinal muscle-layer is well developed, and has embedded in it the oesophageal lacunae, which are consequently separated from the alimentary canal by muscle-fibres.

The vascular system shows a cephalic loop. Large oval corpuscles are a characteristic feature. The dorsal blood-vessel leaves the proboscis-sheath at the hind end of the excretory system. The proboscis has three layers of muscles, and muscle-crosses are present.

The excretory system is small. It is situated in the mouth-region and barely extends beyond it. One pair of ducts is present, opening laterally just over the nerve-cords.

The dorsal lobe of the dorsal ganglion of the brain is well marked. The head-slits reach about halfway to the middle line and are not prolonged behind the brain.

A frontal organ is not present. Eyes are probably represented by a few small structures near the tip of the snout, but the state of preservation does not allow us to be positive on this point.

12. Lineus hancoeki, sp. n. (Plate 1. figs. 6 a, 6i.)

Locality. Cargados Carajos, from the reef.

A single specimen, somewhat fragmentary. The colour when preserved in spirit is a pale yellow-green. The head is markedly spatulate and the mouth very large and open. The general shape is much flattened, but there are no indications of side folds.

The epithelium contains numerous highly refractive unicellular glands and rests upon a thick basement-membrane. The cutis is very poorly developed and is not so thick as the epithelium; it contains a few circular and longitudinal muscle-fibrils and a sprinkling of small glands which abut directly upon the outer muscular layer. There is no gelatinous layer.

A well-marked cephalic vascular loop is present.

There is no proboscis.

The excretory system starts shortly behind the posterior end of the mouth. Its range is only 2 mm. and the tubules are not found either dorsal or ventral to the nerve- cord, but are collected at the edge of the stomach. Careful search did not reveal any ducts.

In the brain the dorsal lobe of the dorsal ganglion is well marked, otherwise the brain presents no features of special interest.

The head-slits are deep, reaching nearly to the brain, and are prolonged beyond the cerebral organs.

A single frontal organ and numerous small eyes are present.

PUNNETT AND FOESTEE OOOPEE— NEMEETEANS. 9

13. Linens indicus, sp. n. (Plate 1. fig. 2.)

Locality. Amirantes, from 19 fathoms.

A single rather slender specimen, 85 mm. in length. The hind end is pointed, the head spatulate and mouth large. The colour of the spirit-specimen is pale green. On the dorsal surface there is a thin white collar running across the brain-region.

There is a well-developed gelatinous layer, but the rest of the cutis is much reduced.

The vascular system shows a well-marked cephalic loop. The median dorsal vessel leaves the proboscis-sheath at the level of the right nephridial duct.

The rhynchocoel extends a good way throughout the body, though it does not reach the hind end.

The excretory system begins at the level of the mouth-ending ; in addition to the usual pair of ducts there is an additional one on the left side.

There is no frontal organ.

The head-slits extend rather more than halfway to the middle line ; they are not prolonged past the brain-region.

Numerous small eyes are present on either side.

14. Lineus crosslandi, sp. n. (Plate 1. fig. 6; Plate 2. fig. 16.)

Locality. Zanzibar (Crossland Coll.).

A single specimen of a small species 65 mm. in length and 3 mm. in breadth. Reddish in colour when preserved, it was probably bright red in life. The tail ends in rather a fine point, but no caudicle is visible. The extruded proboscis measures 45 mm.

Tiie epithelium rests on a very fine basement-membrane, under which is a delicate layer of circular muscle-fibres. The cutis-glands are comparatively small, and among them are found a certain number of muscle-fibres. A fairly well-marked gelatinous layer is present, and constitutes more than half the total thickness of the cutis (PI. 2. fig. 16).

The mouth is large, and begins just before the termination of the cerebral organs.

The vascular system has a well-marked cephalic loop. Owing to internal disruption it is not possible to state where the proboscis-vessel leaves the sheath. The system generally is characterised by the presence of large oval nucleated corpuscles.

The proboscis has three muscular layers, the outer longitudinal being much attenuated. Both muscle-crosses are present.

The excretory system is found in the mouth-region, and abuts upon the vascular lacuna which partly surrounds the cerebral organ. There is a single pair of ex- ceedingly well-marked ducts just behind the mouth.

The testes extend dorsally nearly to the rhynchocoel and ventrally to the blood- vessel. The ducts pass out just above the nerve-cord.

The brain is of the usual type.

The head-slits reach barely halfway to the middle line and end abruptly before the posterior level of the cerebral organ.

SECOND SEEIES. ZOOLOGY, VOL. XIII. 2

10 PERCY SLADEN TEUST EXPEDITION.

A few small eyes are present, and head-glands are fairly well marked. There is no frontal organ.

15. Lineus corrugatus, Mclnt., 1879. (Plate 1. fig. 7.)

Locality. Cargados Carajos, 35 fathoms.

One specimen, 100 mm. long and 8 mm. broad. This agrees with the type in the presence of eyes and the general structure of the body and skin. The only difference that we have been able to discover is that the excretory duct occurs in the hinder mouth-region, while in another specimen of L. corrugatus which we were able to examine the ducts were situated further back.

16. Lineus orientalis, sp. n. (Plate 1. fig. 3 ; Plate 2. fig. 17.) Locality. Coetivy.

A single specimen, 170 mm. long and 5 mm. in breadth .

Colour a brown-green all over, rather paler ventrally, without markings. The oesophageal region is cylindrical, the intestinal region being rather more flattened.

The epithelium rests on a fine basement-membrane, under which is a well-developed gelatinous layer. The cutis-glands are well developed, especially in the anterior region (PI. 2. fig. 17).

The vascular system shows a cephalic loop.

The proboscis is missing.

The excretory system has a single pair of weU-marked ducts near the hinder end of the system.

The cephalic slits reach about halfway to the middle line and are not prolonged behind the brain-region,

A frontal organ and head-glands are present, but there are no eyes.

17. Cerebratulus multiporatus, sp. n. (Plate 2. fig. 18.) Locality. Wasin, British East Africa (Crossland Coll.).

A small specimen, colourless when preserved, measuring 53 mm. in length and 25 in breadth. A caudicle is present.

The epithelium (fig. 18) rests on a distinct basement-membrane, beneath which is a delicate layer of circular muscles. The cutis is feebly developed and the glands, which stain vividly with picric acid, are scanty ; in the postnephridial region, however, the cutis- glands are much more highly developed and form a compact layer. In the oesophageal region the outer longitudinal muscle-layer is about five times as thick as the circular layer, and this again is twice as thick as the internal longitudinal layer. There is no diagonal layer, nor is there a horizontal layer over the mouth.

Tlie mouth-opening is situated immediately in front of the level of the termination of the cerebral organs.

The vascular system exhibits a cephalic vascular lacuna.

The proboscis is small, but contains the usual three layers and muscle-crosses.

PUNNETT AND FOESTEE COOPEE NEMEETEANS. 11

The excretory system begins soon after the mouth-region. There is more than one duct on each side.

The brain is comparatively large and has a well-marked dorsal lobe. The head-slits reach halfway to the middle line and are not prolonged beyond the brain-region.

Eyes and frontal organ are not present, nor could head-glands be distinguished with certainty.

18. Cerebratulus zebra, sp. n. (Plate 1. fig. 11 ; Plate 2. fig. 19.)

Locality. Ceylon, from the pearl-banks of Azipu (Herdman Coll.).

About 80 mm. of the anterior end of a rather large specimen, measuring 8 mm. in breadth.

The colour and pattern of the specimen, which is preserved in spirit, is characterized by irregular transverse bands of dark greyish brown on a pale grey ground. In front of the head-slits there are no markings and the ground-colour is somewhat paler.

The intestinal region is much flattened and there are well-developed side folds.

The epithelium (PI. 2. fig. 19) is very fuU of unicellular gland-cells and the base- ment-membrane is exceedingly thin. A fairly well-developed circular muscular layer is present beneath the basement-membrane, and the cutis-glands project into the outer longitudinal muscle-layer. Pigment-granules occur chiefly among the circular cutis- muscles, but they are also found to some extent in the epithelium.

In the stomach-region the muscle-layers of the body-wall are all thick, the outer longitudinal muscle-layer is twice as thick as the circular, which in its turn is twice as thick as the internal longitudinal layer. Between the outer longitudinal and the circular layers is a distinct diagonal layer. The horizontal musculature so often found beneath the proboscis-sheath is here wanting.

The mouth is small, and begins just behind the level where the cerebral organ ends. The alimentary canal is of the usual Cerebratulus type.

The vascular system shows a cephalic loop. The dorsal blood-vessel leaves the proboscis-sheath a little behind the level at which the nephridial ducts are given off, i. e., at the region where the nephridial system terminates.

The proboscis is wanting.

The excretory system possesses one pair of ducts, which open near its hinder end.

The specimen is a male with ripe spermatozoa ; the genital ducts open on the dorsal surface not far from the middle line. The head-slits are fairly deep, and extend about halfway to the middle line ; they are somewhat prolonged past the mouth.

A small frontal organ is present. There are no eyes.

Head-glands are present, scattered through the musculature of the snout. /i^ .^

19. Biplopleura obocTciana (Joubin, 1887). Locality. Wasin, British East Africa (Crossland Coll.). Colour, when preserved in corrosive sublimate, white. Ties anterior ends together with various fragments.

12 PERCr SLADEN TEUST EXPEDITION.

Our specimen agrees with Joubin's species in possessing dorsal and ventral head- grooves, a feature which separates it from D. formosa. As the material has only reached us in the preserved state, we are unable to state whether the colour was pink like that of a Joubin's specimen. In general anatomical features, such as the reduction of the cutis, the musculature of the side folds, and the dorsal position of the excretory pores, the present specimens agree with the descriptions by Burger and Joubin.

20. Diplopleura sip.

A smaU specimen belonging to this genus was found among certain material from the Maldive and Laccadive expedition too late for inclusion in the report of that expedition.

[Appendix. In the following Tables we have enumerated certain anatomical features which experience has convinced us wiU prove of serAdce in the classification of the species at present included in the genera Cerebratulus, lAneus, and Micrura, and we have tabulated these features in so far as reference to the original descriptions has allowed us. In cases where the records are too meagre for tabulation we have nevertheless mentioned the name of the species. Most of the terms used do not require explanation, but we ought to mention that in the case of the head-slits the term " not prolonged " means that these slits do not extend beyond the hinder limit of the brain. A large black dot in the right-hand column opposite a species signifies that the species so marked is found in tlie Indian Ocean. R. C. P.] 9th May, 1909.

PUNNETT AND FORSTEE COOPEE— NEMERTEAN8.

13

9

'■a

tr

Excretory

Frontal

Head-

Rhyn-

Muacle-

Head-

Eyes

o

s

ducts

organ

slits

choooel

crosses

glands

3

2"

EL

n'

o

3

a

B S

s

s

■d o

•a

o

i

•3

1

■a

3

s-

'H

c

V

Id

M

s

o

o

p

p-

3

3

a

c*

15

^'

'w

"3

c 3

eu

■""

1

"1

a^

p-

3

Cebbbbatulus.

1. ferrugineus ....

*

Note. Noa. 1-34 are ex-

2. uotabilis

p.f

*

tracted from Biirger, ' Das

3. roseus

^

#

*

Tierreich,'1904. In that

4. ruarginatus

*

»

*

*

*

»

»

*

publication the following

5. pantherimia ...

6. tigrinus

7. pullus

8. acteus

jjf

*

*

species occur which are

*

» *

*

*

*

9 too insufficiently known 9 to be entered in these tables, viz :

9. magelhaeusicus . .

*

*

fasciatus.

10. steeiieni

*

*

*

*

»

luridus.

11. aubtilis

*

^

*

*

*

leidyi.

12. validiia

J »

*

*

pochohontaa.

13. hepaticua

*

*

*

striolentua.

14. urticana

*

*

*

«

*

»

barentsi.

15. liguricua

»

*

*

borealis.

16. ventrosulcatua . .

*

*

»

*

*

*

aureolas.

17. angiiillula

*

*

»

»

macrostomus.

18. lividus

*

*

*

*

impressus.

19 fuscus ....

* *

* *

*

»

* »

» *

albulus. niger.

20. fuacoidea

21. joubini

*

sinensis.

22. serugatua

*

*

p*

*

subacutus.

23. ceatoidea

*

P*

, .

rubellua.

24. eiaigi

*

*

»

*

paludicolus.

25. melanorhynchua .

*

»

'r'*

»

caledonicus.

26. simulana

*

*

*

»

oleaginua.

27. spadix

»

28. rubena

*

»

*

No. 8 is completed from Coe.

29. luteus

*

»

30. bicomia

*

»

31. pachyrhynclnia . .

»

*

32. niacrorhynchua . .

*

P*

33. australia

*

34. ruber

35. gracilis

36. latistomachua . .

* * *

* *

?*■

*

*

*

« Noa. 36-38 from Staub (1900).

37. profundiiissus. . . .

*

*

*

38. laureolus

39. hereuleus

40. occidentalia ....

»

*

*

*

?'»

*

••

, .

Nos. 39-48 from Coe

(1901-05).

41. longiceps

*

?*

*

42. montgomerji ....

*

*

»

^0

43. albifrona

*

44. latua

*

»

45. antillensis

*

*

*

46. californienaia ....

*

*

»

47. lineolatua

*

*

48. signatus

49. jiatans

50. robuatua

» #

« *

* *

*

* »

»

p*

*

*

*

Noa. 49-66 fi-om Punnett « (1900, '01, '02, '03).

61. erythrua

*