ALCYONARIANS AN ACCOUNT OF THE ALCYONARIANS COLLECTED BY THE ROYAL INDIAN MARINE SURVEY SHIP INVESTIGATOR IN THE INDIAN OCEAN BY j. ARTHUR THOMSON, M.A. REGIUS PROFESSOR OF NATURAL HISTORY IN THE UNIVERSITY OF ABERDEEN AND J. J. SIMPSON, M.A., B.Sc. CARNEGIE FELLOW, UNIVERSITY OF ABERDEEN WITH A REPORT ON THE SPECIES OF DENDRONEPHTHYA BY W. D. HENDERSON, B.Sc, Ph.D. II. THE ALCYONARIANS OF THE LITTORAL AREA ^ .^, CALCUTTA PRINTED BY ORDER OF THE TRUSTEES OF THE INDIAN MUSEUM 1909 3Z/I INTRODUCTION. This memoir contains a description of a rich collection of Littoral Alcyonarians made by the Royal Indian Marine Survey Ship " Investigator " in the Indian Ocean/ It is a continuation of a previous memoir (Thomson and Henderson, 1906) dealing with the Deep-Sea forms. The collection includes 187 species (sixty-one belonging to Dendronephtliya or Spongodes); 108 are new, but fifty-three of these belong to Dendi'oneplithfia or Spongodes to which additions continue to be made in embarrassing numliers. It has been found necessary to establish four new genera, — Studerioteii appended to the Alcyoniidic, Dacttilonepliihiin appended to the Nephthyidtt, Cactogorgia among Siphonogorgiidai, and Paralwlemnou among the Veretillida;." The following table will show the general nature of the collection and the distribution of the new forms : — 1 1 wish to thank the Trustees of the Indian Museum for giving me the opportunity of studying this fine collection of beautiful forms, and my thanks are also due to Professor A. Alcock, LL.D., F.E.S., formerly Superintendent of the Indian Museum, and to Dr. Nelson Annandale now Superintendent, for their kind assistance in connection with this prolonged and laborious investigation. Prof. Gilbert C. Bourne was good enough to send me a number of specimens belonging to the first " Investigator " collection and a report on these has been included. Through the Carnegie Trust I was able to secure the help of Mr. J. .1. Simpson, joint author of this memoir, whose indefatigable work in this connection was done during his tenure of a Carnegie Scholarship and Fellowship. In the same way I have been able to include a report on the genus Dcndrone- phthya or Sjwnijodes by Dr. W. D. Henderson, who worked at the puzzhng problem of its species during part of the time of his tenure of a Carnegie Fellowship. I have to thank the Carnegie Trustees also for a grant which has defrayed the expense of drawing four of the plates, and the ex- pense of having zinc-blocks made for the text-illustrations. It would be ungrateful not to express indebtedness to the artist, Mr. George Davidson, for his skill and patience. The engraver, Mr. Edwin Wilson, also deserves to be congratulated on the success of his plates, for the coloured ones in particular presented difficulties which have been happily overcome. — J. A. T. - Two of these genera have been previously reported and are here referred to as Studeriotes (= Studeria, Thomson) and Gactorjoryia, Simpson. For the same reason all the numerous new species of Dendronephlhya (or Spongodes) bear the name of Henderson. VI Order. Total Number of Genera in the Collection. New Genera. Total Number of Species in the Collection. New Si5ecies. I. Stolonifera II. Alcyonacea III. Pseudaxouia .... IV. Axifera V. Stelechotokea .... Totals 1 12 5 22 10 3 1 1 90 11 51 34 69 3 23 13 50 4 187 108 New Types. Studeriotes is an Alcyoniid or a Ne})hthyi(l of very remarkable structure perhaps with distant affinities with Paralciioniimi. It consists of a strong densely spiculose cup, within which very numerous finger-like polyp-bearing lobes or branches are retracted ; these arise at different levels from a strong muscular central thalamus, and from the upper parts of the inner wall of the cup ; each finger-like lobe is thickly covered with polyps and ends in one larger than the rest ; the cavities of the polyps communicate with a central canal in the digitiform lobe, and these central canals unite in a few large longitudinal canals with large muscles on their walls and with few spicules ; the polyps have a distinct non-retractile calyx covered with spindles arranged in double rows ; the spicules are all warty spindles, except a few minute irregular forms found (along with sparse spindles) in the canal walls ; many of tlie cortical sjiindles attain huge dimensions, some exceeding nine millimetres. In many respects this is a divergent form, highly differentiated in the direction of retractility of polyparium. The genus Cacto(joniiecinien in this collection to Ehrenberg's original species { = T. musira, Cham.). It is a large fragment, 105 mm. in length and 30 mm. in breadth, of a bright coral-red colour. The diameter of the zooid-tubes is far from uniform, but 2'25 mm. is an average measurement. The tubes are separated by inter- vals of lo mm. The lamelhe are about 1 mm. in thickness and are from 2 to 3'25 mm. apart. Locality : N. Maldive Atoll. Previously recorded frojn N. Maldive Atoll, Zanzibar, Red Sea, New Britain, etc. Order II. ALCYONACEA, Veirill {2>r'> parte). Family AiCYONW.i:. (a) Monomorp/iic. Alcyonium klunzincjeri, n. sp. (/S) Dimorphic. Sarcophytum plicatitm, Sclienk. ,, ehrenbergi, Marenzeller. Lobophjjtitm crassum, Marenzeller. Sclerophytiim hirtiim, Pratt. ,, polydactyluTn, Pratt { = Lohwlaria polydactyla, Ehrenberg). ,, densum, Pratt (= Lobophytitm densitm, Whitelegge). ,, querciforme, Pratt. „■ andmnanense, n. sp. Incerki', sedis : — Stwderiotes mirabilis, Thom.son. GENUS ALCYONIUM, Linn^us. Alcyonium klunzingeri, n. sp. Two exqui.site and distinctive colonies, one of a cream colour, the other pink with just a hint of purple. Both are of an encrusting nature and have been attached to rocks, so that the general basal contour is irregular. The basal portion of the larger is 65 mm. long and 60 mm. in breadth ; similar measurements in the other are 65 mm. and 50 nun. In neither does the height exceed 25 mm. From the flat expanded base numerous small mamilliform lobes arise. The largest of these are about 12 mm. in height and 8 mm. in diameter. They terminate in blunt cones or domes, Init otherwise are cylindrical. Some of the lobes are slightly flattened, and several bifur- cate or even give rise to three smaller lobes. The whole colony may be said to be more hard than fleshy ; the canal walls are densely packed with small spicules. The coenenchymal canals are cylindrical and very distinct; 2 Fig. 1. Alcyonium klunzingeri, n. sp. — A general view of a piece of a colony, natural size. those near the margin are ninch larger than those in the interioi-, but they eventually taper and unite with the more central canals. The polyi)s occur all over the l)asal plate and lobes and are very regularly arranged so that the ccenenchyma forms a sort of reticulate structure. The openings are circular but sometimes appear as small octagons when magnified. The anthocodite are completely retractile. They withdraw themselves until they are within the surface of the ccenenchyma where they appear as octagonal figures formed by the inturning of the tentacles. The regular network which separates the polyps does not contract so as to cover the anthocodia-. The i)olyp openings are about 1 nuu. in diameter and the walls about 0'5 mm. in diameter. They are arranged somewhat regularly in rows which in most cases alternate. Locality : Gt. Coco Island, Andamans. GENUS SARCOPHYTUM, Lesson. Sarcophytum plicatum, Schenk. To this species we refer two colonies, one very large and much convoluted, the other small, mushroom-shaped and regular. The larger is attached to a calcareous nuUipore and has a basal attachment 50 mm. long and 20 mm. in maximum breadth. The whole colony is about 40 mm. in height and has been })rimarily reniform, but by secondary convolutions this scheme is partly obliter- ated ; the margin is verj^ irregular. The texture is "leathery" or may even appi'oach to "hard". The ccenenchymal canals are circular and very definite throughout the colony. The autozooids are fairly large and distant but are much more crowded towards the periphery and on the marginal convexity ; they give the colony a downy appearance when exserted. Eight or nine occur in 1 cm. in rather definite rows ; the openings appear as small pores when the anthocodije are retracted. The siphonozooids are hardly perceptible. The smaller colony is mushroom-shaped and has a sterile stalk 13 mm. long and 12 mm. in diameter ; this is surmounted by an expanded disc about 24 mm. in diameter. The thickness of the central part of the capitulum is about 5 mm. but it tends to become wedge-shaped towards the margin. Con- volutions are still absent. In this specimen the autozooids are larger and the pores more distinct ; the latter are about 1 mm. in diameter. The siphono- zooids appear to the naked eye as dark minute dots. The colour of the larger colony is purplish, that of the smaller brown. This species is described in detail by Schenk (189G), p. 76, Tafel II. fig. 12, Tafel IV. fig. 40. Locality : Mergui and Andamans. Previously recorded from Ternate. Sarcophytum ehrenbergi, Marenzeller. To this species we refer a small colony 25 mm. in height with a sterile stalk, 15 mm. long and 9 mm. in diameter, surmounted by an expanded disc, giving a distinct mushroom shape. The capitulum is saucei'-shaped ; the margin is turned up slightly instead of down as is usually the case. The texture of the colony is leathery, but the spicules are numerous near the surface. The autozooids are large and distant ; some are about 4 mm. in length and are separated by distances of from 2 mm. to So mm. They are more closely packed around the margin. The siphonozooids are large and fairly abundant. The colour of the colony, as recorded at the time of preservation, was a pale dirty chocolate with black autozooids. This species was first described by Marenzeller (1886), p. 356 (Tafel IX. figs. 3 and 4), and again in detail by Miss Pratt (1903), p. 508 (Plate XXVIII. figs. 1 and 2). Locality : Andamans. Previously recorded from Red Sea, Port Denison (Australia), Viti Islands, China Straits (New Guinea), Maldives. GENUS LOBOPHYTUM, Marenzeller. Lobophytum crassum, Marenzeller. To this species as defined by Marenzeller (1886, p. 363, Tafel IX. figs. 8, 9, 10 and 11), we refer a small young colony somewhat mushroom-shaped. It consists of a sterile stalk 20 mm. in length and 5'5 mm. in diameter at the base, but gradually increasing to 10 mm. at the top, where it is surmounted by a much-convoluted capitulum. The whole colony is hard and rigid and is abun- dantly supplied with small spicules. The coenenchymal canals are large and distinct ; they are cylindrical almost to the base of the colony. The autozooids are small and have minute pores. They are very distant and are separated by intervals of 2"5 mm. to 3"5 mm. The siphonozooids are minute and numerous ; they are very crowded and give the colony a pitted appearance visible to the naked eye. The colour is pale yellow to cream. This is a very variable species. Marenzeller distinguishes four varieties ; (1) L. crassum (type), from Port Denison ; (2) L. cmssum, var. borbonicum, from Island of Reunion ; (3) L. crassum, var. crista-galU, from Tonga ; and (4) L. fvas- siim, var. prolifera, from Port Denison. Our specimen is young and immature so that we do not feel justified in ranking it under any distinct variety. Locality : Pedro Shoal. Previously recorded from Port Denison, Reunion, Tonga, Loyalty Islands. GENUS SCLEROPHYTUM, Pratt. Sclerophytum hirtum, Pratt. We assign to this species a colon}' whicli while ditFering considerably from the type .species as described by Pratt (1903), p. 522, PI. XXX. figs. 23-25, nevertheless agrees in all essential characters. There is practically no stalk visible ; the colony is excessively convoluted, and the margin has become turned down so that it reaches to the place of attachment to the rock. The total height is 50 mm. while the two breadths are respectively 110 mm. and 75 mm. There cannot be said to be any distinct lobes ; the colony is tough and Heshy. The autozooids are regularly (listril)uted over the whole colony at distances varying from 1 mm. to 15 mm. ; when expanded they are about 1 mm. in dia- meter. The siphonozooids are very minute and are not visible to the naked eye. The colour of the colony is almost olive-green. Locality : N. Andaman Island. Previously recorded from Naifaro Reef, Fadifolu Atoll, Maldives. Sclerophytum polydactylum, Pratt. { = Akyon'mm polydartylain, Dana, "Zoophytes," p. 617.) { = Alctioninm pohidnctyJmn, Klunzinger, "Die Korallthiere des Rothen Meeres," p. 26, Tafel I. figs. 6a to f.) { = Lohrdarid polydddyhi, Ehrenberg, "Korallthiere," p. 58.) { = Lohtdari(i polydiirtyht, Milne-Edwards and Haime, " Coralliaires," I. p. 121.) {^Ammocellapolydactyla, Gray, "Ann. Mag. Nat. Hist." p. 125, 1869.) This species was included in the genus ScUrophylmti for the first time by Miss Pratt (" Alcyonaria of the Maldives," 1903, p. 524). It is represented in the present collection by a portion of what has evidently been a large colony, but the base is wanting. The specimen is 50 mm. in height, 70 mm. in maxi- mum breadth, and 20 mm. in thickness. The lower part does not bear polyps, but above this region irregular finger shaped lobes arise, one of these again bearing secondary lobes. The specimen is tough and fleshy, but the coenenchyma of the lower part bears numerous large spindles. The autozooids are small ; they are about 05 mm. in diameter and are separated by intervals of 1 to 125 mm. No trace of siphonozooids could be found. The colour of the specimen is a pale chocolate. Locality : Mergui. Previously recorded from the Red Sea (Klunzinger and Ehrenberg), New Guinea (Hickson and Hiles), Maldives (Pratt). Sclerophytum densum, Pratt. iy-^ Lohopli Ilium dermmi, Whitelegge, " Alcyonaria of Funafuti," 1897, p. 219. Plate XL figs. 4a to li.) See Pratt, "Alcyonaria of the Maldives," 1903, p. 521. Plate XXIX. fig. 18; Plate XXX. figs. 20-22. This species is represented by a portion of a colony, evidently a primary lobe, 60 mm. in height, ^l'^ mm. in breadth, and 18 mm. in thickness at the base, but tapering almost conically to a diameter of 9 mm. where it divides into two finger-shaped processes. Just below this division two small lobes arise almost close together, each about 10 mm. in length and 7 mm. in diameter. The ccenenchyma is densely packed with large opaque white spicules which make the colony very hard. The autozooids are large and fairly numerous. Some are about 2 mm. in length and 1 mm. in diameter. They are separated by intervals of about 1 to 1"5 mm. in the lobes, but are more distant on the older jjortion. This agrees well with the description given by Whitelegge, but Miss Pratt says that the autozooids are " very numerous ". The siphonozooids are almost imperceptible even with a strong lens. There is a furrow about 3 5 mm. broad and 1'25 mm. deep along one side of the colony between the two lobes ; this is devoid of autozooids. The colour is almost jet black. Locality : Andamans. Previously recorded from Funafuti (Whitelegge), Addu Atoll, 11 fathoms ; Plulule, Male Atoll, 25 fathoms ; Felidu Atoll, 34 fathoms ; Maklives (Pratt) ; Sandal Bay, Lifu (Pratt) ; China Straits, British New Guinea (Pratt). Sclerophytum querciforme, Pratt. To this species, defined by Pratt (1903), ("Alcyonaria of the Maldives," p. 530. Plate XXXI. fig. 33), we refer two very robust, arborescent colonies of an almost jet black colour. The larger colony is 80 mm. in height and 100 mm. in maximum breadth ; the basal attachment is 45 mm. long and 35 mm. broad. The smaller is 45 mm. high and about the same in breadth ; there is practically no stalk ; the branches arise almost from the base ; the lolies are finger-like. In the larger specimen the main stem gives off several branches and these again bear secondary and sometimes tertiary lobes. The surface is very rugged ; the texture is leathery ; the main stem is densely packed with large spicules. The autozooids are numerous ; they are separated by intervals of about 1 mm. and are about 5 mm. in diameter. Siphonozooids do not occur. Locality : Andamans. Previously recorded from Hulule, Male Atoll ; Maldives (Pratt). Sclerophytum andamanense, n. sp. We reluctantly add to the already long list of species in this genus, but the characters of the present specimen, though ap[)roaching >S'. tnhemilosum (Loho- plijitiim tuhfrcidosum, Quoy et Gaimard), mark it oft' as new. The colony is low and spreading ; the basal attachment is 55 mm. lonti; and 25 mm. broad. The stalk is very indefinite ; on one side of the basal plate it rises to a height of 22 mm. but it is altogether absent on the other side, so that the polyp-bearing capi- tulum extends to the very base. The margin of the capitulum is very much convoluted, especially on the side where the stalk is apparent. The colony may be said to be fleshy and tough, but there is an abundance of spicules in the stalk and central portion of the capitulum. The autozooids are large, and when expanded are over 2 mm. in length and 1 mm. in diameter ; the tentacles are quite visible to the naked eye. When the polyps are partially retracted the tentacles are infolded and form a beautiful eight-rayed star. The orifices are 075 to 1 mm. in diameter ; they are separated by distances varying from 1 to 2 mm., but at the margin they are more crowded, so that even when the auto- zooids are partially retracted and have the tentacles unfolded they almost touch. The siphonozooids are extremely minute or altogether aljsent. The colour of the colony is greenish-brown. Locality : Andamans. Fit 2. Sclerophytum andamanense, n. sp. — A general view of a piece of the colony, natural size. GENUS STUDERIOTES. Studeriotes mirabilis/ //. nom. ( = Studeria mirahilis, Thomson). The collection includes a specimen from the Andamans which is cer- tainly one of the most remarkable of the many interesting representatives of this sub-class that have been discovered within recent years. It is a cup-like Fig. 3. Longitudinal section of Sludenotes mirabilis. — Natural size. Fig. 4. Tlie upper part of one of the digitiform polyp-bearing lobes or branches of Studeriotes mirabilis. — It shows the terminal polyp much larger than tlie others. X 12. colony, with a large retractile polyparium. The cup is 45 mm. in height by 55 mm. in maximum diameter, and it is continued into a basal wisp (19 mm. in length), which, however, shows no attaching disk. The specimen gave indication of having been imbedded in the mud up to al^out the maximum diameter of the cup. General Structure. — The most striking peculiarity of Studeriotes is that the whole of the polyp-bearing portion is retracted within the exceedingly substan- tial, densely spinose cup, the circular mouth of which is about 30 mm. in diameter, and shows the tips of numerous finger-like polyp-bearing lobes or 1 I have named this very interesting type in honour of Professor Th. Studer, of Bern, who has contributed so largely to our knowledge of Alcyonaria. I gave a description of it at the Inter- national Congress of Zoologists in Boston (.August, 1907) and at a meeting of the Eoyal Micro- scopical Society, 18th November, 1908. See " Journ. Eoyal Micr. Soc," December, 1908. I had named it Studeria, unaware that this name was pre-occupied for a sub-genus of fossil echinoids. —J. A. T. luaiu'lios. Tt sooms quite likely that the mouth of the cup was capable of more complete closure, and, on the other hand, that the retracted ])olyparium was capable of considerable protrusion. A longitudinal median section of the singles specimen shows a dome-shaped fleshy centre, or thalanuis, from the margins and summit of which most of the numerous lingerdike polyp-bearing lobes arise. Some of them, however, are attached to the inner wall of the cup at different levels. The central dome, it should be noted, rises (j[uite freely in the middle of the cup ; its diameter is Fig. 5. Spicules of Stnderiotos mimbilis. — A. From the stalk. B, From the internal wall of the cup. C. From a polyp-bearing lobe. greater than half the maximum diameter of the cup. The arrangement of the polyp-bearing lobes may be compared to the distribution of carpels and stamens in the flower of some of the Rosacete, in which the former ai'e disposed on a dome-shaped centi'al thalamus, and the latter on several whorls on the inner wall of the " calyx-tube ". Or, again, the central region of our specimen may be compared to the disk of a Composite's capitulum and the peripheral parts to the ray-florets. Fig. 3. There are large longitudinal canals in the central dome, separated by tough hyaline mesogloea. Very strong muscle-bands pass down their walls, and there are others in the wall of the cup reaching almost to the margin. These longitudinal bands pas.s for a short distance into the wis[)-like stalk and gradually disappear. Numerous well-defined transverse muscles extend be- tween the several longitudinal bands. Tfie Cup.— The cortical part of the wall of the cup, which is very definite and has a thickness of about 2 mm., is extremely hard, consisting mainly of long 2 10 spindles, readily visible to the naked eye (some over 5 mm. in length), arranged for the most part in longitudinal interlacing rows. On the surface many of the spindles lie exposed throughout their whole length. Towards the base of the cup the spicules increase in size, and they attain their maximum dimensions — almost 1 cm. in length — in the basal wisp. These are probably the largest Alcyonarian spicules as yet known. The internal part of the wall of the cup, as distinguished from the hard cortex just described, is soft and muscular. It is about 9 mm. in thickness where it joins the base of the dome, and narrows gradually to the margin of the cup. The System of Canals. — Each of the finger-like polyp-bearing lobes has a large canal, with which the cavities of the polyps communicate. These branch canals pass into the dome or the wall of the cup, as the case may be, and uniting with others form the main longitudinal canals. These are relatively large, especially at the base of the cup and below the central dome, where they are about 2"5 ram. in diameter. From this region of maximum size, they gradually taper into the wisp-like stalk. The walls of the canals bear the strong longitudinal muscle-bands, and there are very few spicules. Polyp-heariiuj Lobes or Branches. — Looking down into the mouth of the cup, one sees the heads of between sixty and seventy polyp-bearing lobes or branche.s, but the number visible will of course depend on the degree to which the dome is contracted. Besides the branches on its summit, the central dome bears four whorls, and there are also four tiers on the wall of the cup. It should be noted, however, that the lobes do not all arise singly from the central dome, but may cohere for a distance of 2-6 mm. at their bases. Some are united in pairs ; in one case seven were found to be cohering. Poli/ps. — Each of the finger-like branches resembles a spike-inflorescence, and bears 150-200 close-set sessile polyps. These almost cover the surface, but without discernible arrangement. At the summit there is a terminal polyp which is larger than the others. In many cases a branch has a length of 15 mm. and a maximum diameter of 3 mm., but in regard to these and other Fig. 6. View of the colony from above, showing tips of polyp-bearing lobes occupying the mouth of the cup. — ^About natural size. 11 measurements of soft parts it must be remembered that the whole colony has been much contracted by preservation in strong spirit. Fig. 4. The polyps have almost globular calyces or verruca?, w^ith a diameter of about 1 mm. The tentacles are in most cases completely retracted, and the summit of the calyx shows a sharply defined circular aperture. The polyps with their calyces and precise circular aperture recall those of some of the Pennatulids, such as Virgularids. On the wall of the calyx there are eight triangular points, each consisting of two to three pairs of spicules arranged en chevroti, surmounting a collaret of several horizontal rows. In most cases, however, the projecting spindles of the cortical crenenchyma hide the base of the calyx and may even intrude upon it. The polyp itself is very minute and is completely retractile within the globular calyx. The tentacles are short and thick, apparently without spicules, and with about half a dozen pairs of pinnules. Spicules. — Apart from a few irregular minute forms found on the canal walls (and possil)ly extraneous), all the spicules are spindles. Many are huge, most are densely warted. The warts are often in close set transverse rows, so that the spindle has a striated appearance. Many of the spindles are curved in a sinuous fashion ; not a few are irregularly forked. Fig. 5. The following measurements were taken of the spicules, length and breadth in millimetres : — From the stalk : 95 x -534 ; 7 x -51 ; 575 x -476. From the cortex: 55 x -476; 3-5 x -28; 1-75 x -153. From the inner wall | 5 , .4 3 , .gg ; 2 x -15 ; 1 x -125 ; -9 x -1. of the cup : J From the canal walls : 6 x -51 ; 4*25 x -4 ; 275 x 32. From the polyps : 16 x 112; 102 x -05; 45 x -034 ; 17 x 018; •13 X 017. Position of St ude notes. — If this type is to be referred to any of the recog- nised families of the Alcyonacea it must be to the Alcyoniida? or to a position between Alcyoniidte and Nephthyidtie. In the retractility of the whole poly- parium, as well as in the mode of branching, the disposition of the polyps and their armature, it is removed from the Nephthyids and Siphonogorgids. In certain respects, e.g., the distinct calyces into which the delicate upper parts of the polyps are retracted and the large longitudinal canals continued in part to the base of the colony, Studeriotes resembles Nidalia, but the Nidalia colony is unbranched, and there are many other differences apart from the retractile polyparium. In certain respects, e.g., in its huge spindles and in the finger-like lobes densely covered with polyps, Studeriotes resembles a form like Sclerop/ti/tum polydactglam, but the polyps are quite different in the two, and there is not in Studeriotes any hint of dimorphism. The non-retractile calyces, 12 the mode of branching, the nature of the spiculation, and other features separ- ate Studeriotes from A Ici/onimn and several nearly related genera. »So we might review all the genera of Alcyoniidtie, but to little profit, for there is only one which can be thought of as having close affinities with our new type. That one is the genus Fanilri/onlmn, established by Milne-Edwards. Milne-Edwards gave the following diagnosis of P((r((Icyonimn : " Polyparium of a coriaceous tissue towards the base and there forming a cylindrical tube with spiculose walls, into the interior of which all the upper and soft part of the polyparium, including the polyps themselves, can be completely retracted " (" Histoire Naturelle des Coralliaires," 1857, p. 129). In his original description of Piindriiouiiiiu, when he called it Alcyonide ("Ann. Sci. Nat.," ser. 2, iv. (1835), pp. 323-33 (9 figs.)), Milne-Edwards gave a number of interesting details. He distinguished a brown firm " foot" fixed by its base, and a white, delicate, l)ranched trunk with twigs ending in small polyps. The cavities of the polyps unite in forming longitudinal canals which are continued to the base, tho.se which lie to the outside having their walls strengthened by numerous brown spindles. Ova are developed on lamelhe in the lower part of the canals of the trunk and fall into the cavity, accumu- lating further down. On the polyps there are, according to Milne-Edwards, rows of "spicules cartilagineuses brunatres". Wright and Studer gave the following definition of Paralcyonium in the "'Challenger' Report" on Alcyonarians (1889): "The colony presents two distinct portions : one, the basal portion, is dense, with firm walls ; the other, the head, alone bears the polyps, and can be in part withdrawn into the basal part. The polyp-bearing portion is but feebly lobed." In his " Versuch eines Systemes der Alcyonaria " (" Arch. Naturges.," liii. (1887)), Studer had suggested affinity with Nidalia. Our new type StndeHotes agrees with Paralcjionima (1) in having the polyp- bearing portion retractile into the basal portion ; (2) in the dis[)osition of the longitudinal canals, and (3) in having very large fusiform spicules. But there the resemblance stops, and there can be no question as to the distinctiveness of the two very remarkable genera. The most obvious differences between Studeriotes and Parcdciioimun may be summed up in the following contrast : — Studeriotes mirabilis. Paralcyoiiiivni eleijans. The polyps are crowded on numer- The polyps are distant from one ous finger-like branches, which cover another, and are borne on the ends a central dome, and also grow out from of the twigs of a loosely-branched the inner walls of the cup. polyparium. 13 Studeriote>i viindiilis — cont. Paralciionium elegans — cant. The polyps have a dense armature The polyps have minute spicules at of spicules, forming a well-defined the base of the tentacles, but there is calyx. no calyx. The walls of the cup are very massive The walls of the cylindrical lower and hard. portion are not thick, and the whole is readily compressible. The retractile polyparium is very The retractile polypariuin is very substantial, including strong muscle- delicate and translucent, bands. The larger spindles are very char- The spindles are much smaller, and acteristic, being covered with warts in much less warty, thick-set rows. It should be noted that Studeriotes mirahilis is much larger than Pund- ciionjam ch'tjam, much more massive, with much larger and coarser spicules, and so on ; but we have reason to believe that the massiveness of architecture is a specific, not a generic character. We saw in Se]jtember in the Zoological Museum in Hamburg a number of unnamed specimens of a form which we believe to be closely related to Studeriotes. By the courtesy of the director, Pro- fessor Kraepelin, and of Dr. Michaelsen, who has charge of the section of the museum containing Alcyonaria and the like, we were able to examine this form, and to compare it with the "Investigator" type. The Hamburg specimens, which were collected off Formosa (Takao), agree with the " Investigator " speci- men in having a reti-actile polyparium, similar polyps, and the same type of huge warty spindle, but they have not the strong massive cup, nor, so far as we have seen, the same development of central dome, or of digitiform lobes. We do not wish to pursue the comparison in the meantime, since Professor Kiikenthal has, we believe, undertaken to describe the unnamed Alcyonarians in the Hamburg Museum. We would, however, express our conclusion that the Hamburg specimens belong, or are closely related, to the genus Studeriotes, which we have established for the " Investigator " type. M. Camille Viguier ^ has described and given beautiful figures of a type which he calls Fascicularia, and has proposed to include Paralcyonium along with it in a special family or sub-family, Fascicularinaj. But it is not evident that Finicu-uhirla is really related to Pdralcijoniiim : it consists of groups united by stolons ; the cavities of the polyps are continued, quite distinct from one 1 Etudes sur les animaux inferieurs de la Bale d' Alger. III. Un nouveau type d'.^nthozoaire {Fascicularia edrcardsi). "Arch. Zool. Exp6r.," ser. 2, vi. (1888), pp. 351-73 (2 pis.). See also H. de Lacaze-Duthiers : Coralliaires du Golfe du Lion. Alcyonaires. " Arch. Zool. Exp6r.," ser. 3, rai. (1900), pp. 353-462 (i pis.). 14 another, down the " basilar column " ; there is no common region except the base ; the large polyps expand from the top of the basilar column, but there is no branched or lobed poly])arium ; in fact, as the author says, there is no polyparium properly so-called. He makes the same remark, it is true, in regard to Pai-alcyoniiim, which, however, he had not seen. What at once marks Paral- cyonium as distant from Fagcwularia, is the presence of a branched polyparium rising from the top of a firmer cylindrical stalk, into which it can be retracted. Viguier speaks of the " incontestable resemblance " between his Fasckulana and the Parahyoni/im of Milne-Edwards, but we are unable to share this view. The description of Fuscirtilarm suggests to us relationship with Sympodium rather than with Paralcyonimu. A recent careful study of abundant material of Fasciculuria and Paralcy- onium by Sophie Motz-Kossowska and Louis Fage ("Contribution a I't^tude de la famille des Fascicularides," Arch. Zool. Exper., vii. (1907), pp. 423-43 (10 figs.)) corroborates Viguier's view. In their interesting pajjer the authors point out that the two types agree (1) in having a stolon connecting the colonies (but this is often almost suppressed in Pandcyouinm) ; (2) in having a rigid basal portion into which the polyps can be retracted (but in Fascicularia this is com- posed of the unfused gastric cavities of the polyps, wiiereas in Paralcyoniiim there has been much coalescence, and therefore far fewer longitudinal canals than polyps ; moreover, Paralcyon'mm has a branching polyparium with second- ary polyps arising from primary polyps) ; (3) in having similar spicules — small flat, opaque elliptical forms in a sub-tentacular collar and larger spindles in the basal portion (but the spindles are very much larger in Paralcyoniiim). The authors point out that I'dndr.yonimn passes through a Fascieidaria stage, and in spite of the great difference in the basilar portion and in the relations of the polyps to one another, they unite them in the family Fascicularidtt, defined as follows : " C'olonies very poor in ccenenchyma, composed of several groups of polyps united by a stolon ; polyps united at the base in a rigid column within which they can be completely retracted ". It is suggested that the family is connected by Fascieularia with the Clavularidai, that there are some affinities with Nidalia and Nidaliopsis, and that the nearest related form is Onjaiiklm. The armature of the polyps in Nidalia, its unbranched habit, and many other features separate it far from Paralcyonlam, and Ger^emia, to which, as Kiiken- thal has shown, Oiya/iidax must be referred, is equally remote. We have not as yet been able to procure a specimen of Fascieidaria for examination, and we would not therefore dogmatically exclude the possibility that Fascieularia, Paralcyoniuia and Stiideriotes form a series showing the jiro- gressive differentiation of a rigid basilar portion into which the rest of the colony can be retracted. The descriptions given by Motz-Kossowska and Fage are very precise, and their discussion of the possible relationships is admirable ; 15 what surprises us is that in spite of the differences which they indicate between Fifsriniluria and Paralctioniitm, they should propose to include the two in one family. From their descriptions, as from Viguier's, it appears to us that Fatn-intldrhi is more nearly related to Siimpodiion than to Pantlrijoiiiiim ; that it differs from Paralciinniiim too markedly (in the structure of the basilar portion and in the relations of the polyps to this and to one another) to allow of their being included in one family ; and that neither is nearly related to Stitderiotes. Diaiiinmx of Staderiotes. — A colony consisting of a strong densely spiculose cup, within which very numerous finger-like polyp-bearing lobes or branches are retracted ; these arise at different levels from a strong muscular central thalamus, and from the upper parts of the inner wall of the cup ; each finger- like lobe is thickly covered with polyps and ends in a polyp larger than the rest ; the cavities of the polyps communicate with a central canal in the digiti- form lobe, and these central canals unite in a few large longitudinal canals with few spicules in their walls ; the polyps have a distinct non-retractile calyx or verruca, covered with spindles arranged in double rows ; the spicules are all spindles, except a few minute irregular forms found (along with sparse spindles) in the canal walls ; many of the cortical spindles attain huge dimensions (over 9 mm. ) ; many are sinuous and forked ; almost all are very warty, and there is a characteristic arrangement of the warts in transverse rows. Our general conclusion, which is based on a single specimen, of which we had to be careful, is that we have to do with a very distinct genus, related to Paralryoiiiiim, but not very closely ; perhaps connected through forms like iVidd/ia with other Alcyoniidae ; but more probably deserving, as Professor Verrill suggested to us, the establishment of a new family. Family Nephthyidm. Sub-family Spongodinse. Nephthya glomerata, n. sp. ,, tenuispina, n. sp. Dendronephthya (syn. Spongodes), numerous species. GENUS NEPHTHYA, Savigny. Nephthya glomerata, n. sp. Several specimens of an orange-brown colour markedly flattened in one plane. The largest, which is 55 mm. in height, 40 mm. in breadth, and 15 mm. in thickness, is attached to a piece of bivalve shell. It consists of an almost cylindrical stalk, about 15 mm. in diameter, from the lateral surfaces of which 16 Fig. 7. Nephthya glomerata, n. sp. — Gen- eral view of a piece of the colony. Enlarged about eight times. arise nine polyp-bearing lobes, five on one side and four on the ether. These again bear smaller catkin-like outgrowths covered with polyps. The surface of the central portion is paler in colour than the polyps and pre- sents a glistening arenaceous appearance, and when viewed with a lens appears transversely corrugated. Embedded among the smaller spicules are a number of long warty spindles arranged transversely. The canals are large and almost cir- cular in section ; they ai'e few in number, and are supported by thin walls which contain very few spicules. The outer wall is tough and hard ; it is densely packed with small spicules and forms the support of the colony. The polyps ai-e disposed over the whole surface of the lobes, sometimes appearing almost as if in whorls. On the main trunk small groups occur, some- times arising directly, at other times having a short support. The polyp-stalk is about 1"25 mm. in length and the body about 1 nun. They are supported by a fairly definite " Stiitzbiindel " consisting of four to six thick spindles, the uppermost pair of which generally project for a short distance. The orientation of the polyps is such that all the oral openings are directed towards the sup- porting lobe and are closely apposed to it. On the body-wall the spicules are arranged " en chevron " in eight groups which form definite ridges culminating in triangular points at the base of the tentacles. On the aboral surface of the tentacles the spicules are arranged "en chevron". The spicules are chiefly spiny and warty spindles, but small irregular bodies occur in the outer wall. The spindles vary greatly in proportion of length to breadth : in some the spines are much elongated and in others they are bifur- cated. The following are some of the measurements length by breadth in millimetres : — (a) " Stutzbiindel," 15 x 015 ; 17 x 012. (b) Polyp, 0-8 X 012 ; 1 x 014. {(■) Outer wall, sjiindles, 1 x 0075 to 0-3 x 004. Irregular forms, 0-015 x 0015 ; 001 x 001. Locality : Gaspar Strait, East Coast of Sumatra. 17 Nephthya tenuispina, n. sp. Several small but complete colonies attached to pieces of rock, the largest is 3 cm. in liei<;lit. Kioni a si)rea(ling base, 1"8 cm. in diameter, the main portion arises, but this soon gives origin to several long, sliglitlv tapering lobes. These diverge in all directions, some even growing downwards. Polyp-bearing lobes occur all over these secondary branches. A cross-section through one of the larger lobes presents a radiate structure, the canal walls passing from the centre to the circumferenc^e, but this becomes ob.scure in the older portions by the development of smaller canals towards the periphery. The outer wall is tough and rigid and is densely filled with long spiny S[)indles. The polyiJs are borne on catkin-like out- growths of the larger lobes, but on the main stem they occur in groups separated by considerable intervals — seldom singly. The surface of the whole colony is covered with long, straight or curved spindles, generally arranged in groui)s and disposed longitudinally. On the smaller lobes, where the polyps are more crowded, the arrangement is much more irregu- lar, but here also the grouping is a marked feature. The polyps are almost 2 mm. in length, the stalk being slightly over 1 nun. The " StUtz- biindel " consists of about six long thick spindles, grouped into a sheaf, projecting for a considerable di.stance beyond the origin of the body of the Fig. 8. Nephthya tenuispina.n.sp. 1 ^ — The top of two branches, 1 ^I* enlarged about eight times. The polyp stands at right angles to the stalk and is directed towards the colony, but when the tentacles are fully retracted the oral part projects downwards. Spicules longitudinally arranged cover the whole surface, but there is a hint of eight groups at the base of the tentacles. The spicules are straight and curved, spiny and warty spindles and present the following range of measurements length by breadth in millimetres : — 1-0 X 0-15 ; 1-5 X 0-12 ; 09 x 004 ; 07 x 003 ; 03 x 002. This species is remarkable for the great slenderness of the spindles. Locality : Andamans. Marine Survey. 18 Genus Dendronephthya, Kiikenthal { = Sj^rngodex of most autliors).' The classification adopted is that given by Prof. Kiikenthal in his " Versach einer Revision der Alcyonarien " (1905). The genus SpoiKjodes was established in the year 1834 by Lesson for a species described by him, Sp. celosia. Dana changed the name to .S/>(y////w/y/f (1846) with- out giving any special reason, and placed in this genus Alciionium floridum, Esper, in addition to Sp. rflosia, Lesson, and a variety S/k cc/dsid /3 nrhnresrenK. Milne-Edwards (1857) gave an account of the differences between Spq/godes and Neplitliiia, and curiously enough his descriptions are based not on Sp. celima, Lesson, but on Dana's Sp. celosid y8 ai-boreseens. J. E. Gray (1859) fii'.st placed Spnggodia in the genus Nephthpa, but later adopted Lesson's genus and divided it into two sub-genera, Spoggodes and Spoggodia. Klunzinger (1877) placed Spongodcf! along with N('plitliii(t and Ammathea, but while adopting Gray's sub-genera gives them a different diagnosis. Our knowledge was extended when Wright and Studer published (1SS9) their account of the "Challenger" Alcyonaria. Holm (1895) separated Xcphthiia from Spon- godes, and divided the whole genus into four sub-genera. In 1896 Kiikenthal separated Spongodes from Nephthya, and his classification has lieen followed by Burchardt (1896), May (1899) and Piitter (1900). In 1905 Kiikenthal pointed out that the great diversity of diagnoses given for the genera Spongodes and Spongodht, and the fact that the genus Spongodes was founded for what is now Xep/it//i/a celomi, made it necessary to withdraw the name Spongodes. He proposed to replace the genus Spongodes by the two genera Dendronephthya and Stereonephthya, and gave precise definitions of these. The collection is remarkable for the large representation of the Dh-iiricatce and Umhellativ divisions of Kiikenthal's classification and also for the large number of forms that seem to lie on the border line between the main divisions. DIVISION GLOMERAT.^. Dendronephthya irregularis, Henderson. This species is founded for a large colony of about 16 cm. in length and about 12 cm. in greatest breadth. The stalk oi' trunk is long, measuring about 5 cm., greatly shrunken, and 1 As mentioned in the introduction, the description of the species of Spo7igodes or Dendro- nephthya is the work of Dr. W. D. Henderson ; and the new species, which have been very briefly reported in the Zoologischer Anzeiger, must therefore bear his name. It may be noted that Mr. Henderson did this work during part of the time of his tenure of a Carnegie Fellowship, and in Prof. Kiikenthal's laboratory in Breslau. I wish to take this opportunity of thanking my German colleague for his generous assistance in this and other instances. 19 marked liy numerous large longitudinal ridges and furrows, and having its upper portion partially hid by the reflexed flattened branches. It is leathery in texture and granular in appearance. The polyparium is very large, markedly flattened in one plane, and consi.sts of a number of principal branches which rise on opposite sides of the stem in the same plane. Each of these bears secondary branches from which smaller branches are given off. These again, by repeated division, give rise to the polyp- bearing twigs. All over the stem and principal branches smaller branches arise which bear the polyps in clusters at the tips. The lower branches are flattened, fold-like or leaf-like expansions, two of which are very large and almost sui"- round the stem, and give off from their upper surface ordinary branches. Slightly below these a number of smaller branches are given oft' which are cylind- rical in the lower portion and flattened in the upper portion, and slightly above the two large flattened liranches other smaller branches, flattened in their upjier poi'tions, are given oft'. The whole polyparium is characterised by the promin- ent branching, and liy its loose, open appearance, the marked flattening in one plane, and the leaf-like lower branches. The polyps are arranged in small clustei's at the end of small twigs which arise not only from the small branches but also from the general sui-tace of the stem and larger branches. They also occur singly or in still smaller clusters on the edges of the flattened branches. The spicules are arranged in the following manner : at the base there are eight double rows of about two j)airs of spicules each, then above these a number of irregularlj' arranged spicules, and rising- above the latter eight points in each of which there is one jjair of converging spicules. The spicules average about 0o2 mm. in length, but the upper- most measure about 4 mm. and may project a little beyond the polyp. On the aboral surface of each tentacle there are two rows of small flat spicules. The Stiitzbundel is poorly developed, and contains only a few spicules, one or two of which reach a length of 0'9 mm. and scarcely project beyond the polyp. In some cases the Stutzbimdel is more strongly developed and contains larger si)ieules. Cortical spicules : (n) In the stem there are long, slender spindles with numerous regularly arranged, simple spines, and a few small, flat, smooth spindles with toothed edges. The larger spindles average about 17 nuu. in length. (/>) In the stalk there are spindles, three and four-rayed forms, Y-shai)ed forms, and numerous small, incipient three- and four-rayed forms whose centre bears a distinct X-shaped marking, irregular spindles, branched in various ways, flat disc-shaped forms, irregular clubs and stars. All have a marked striation on the surface, and the majority have prominent rough, simple to branched spines, while some have fewer and simpler spines. The spindles also 20 show an aggregation of the spines on the convex side, and in these eases, the spines are usnally strongly developed. The spindles average about 1 mm. in length. Canal-wall spicules : (a) In the stem the canal walls are thickly tilled with small, flat, spindle-shaped to star-shaped spicules. {/j) In the canal walls of the stalk there are a very few spindles and star- shaped forms and numerous very small disc-shaped bodies. Colour — The stalk is greyisli-white ; the stem and larger branches white to semi-transparent with a yellowish-brown tinge ; the remaining branches and twigs, light brown to deep brown ; the polyps white. Locality : Andamans. Dendronephthya ovata, Henderson. A small specimen al)Out 7 cm. in total height and about 3 cm. in greatest breadth. / / Fig. 9. D. ovata. Fig. 10. D. ovata.— Spicules of stalk cortex. The stalk or trunk is long (4 cm.), fairly thick and greatly shrunken. It is leathery in texture, granular in appearance, and has the upper portion hidden by reflexed flattened branches. The polyparium is egg shaped, slightly flattened on one side, that side having less well-developed branches. Two of the lowest branches are flattened leaf-like .structures and almost sui'round the stem, leaviuij; only two small free 21 spaces ill wliicli two small ordinary hranches arise. Slightly further up the stem one or two large branches arise, and all round the stem and larger branches, smaller branches are given off which by division give rise to the polyivbearing twigs. The polyps are arranged in small groups of about five each, anil are placed at practically a right angle on a stalk of about l"o mm. in length. The heails are low and round, measuring about 0'48 mm. in height and 0o6 nnii. in breadth. The spicules are arranged in the following manner : At the base of the polyp there are a few irregularly ari-anged spicules, sometimes bluntly converging, sometimes horizontally placed ; then a ring of horizontal spicules, three deep ; and rising above this eight points each consisting of a single pair of convergingsp icules. In the points there may be a third spicule lying- parallel to one of them. The lower spicules average about 033 mm. in length and the upper about 0-6 mm., but the upper may reach a length of 0"9 mm. and project for a distance of 03 mm. lieyond the polyp. The Stiitzbimdel is well develoi)ed, one of its spicules usually reaching a length of about 26 mm. and projecting more than O'S mm. beyond the polyp. Cortical spicules : (k) In the stem they are thickish spindles, blunt at the end, with numerous rough, blunt spines, the larger averaging 1 mm. in length, the smaller, about 0'6 mm. (/>) In the stalk there are short and broad spindles which show great varia- tion in length but a more marked variation in breadth ; they are straight or curved and may be even C-- and S-shaped. A few show two whorls on their surface. There are also a very few incomplete three-rayed forms. All bear numerous multituberculate warts. Smaller spindles average 0"6 mm. in length, larger spindles are about 1'35 mm. long and about 0'22 mm. broad. Spindles up to 2-25 mm. long and 04 mm. broad are present. Canal-wall spicules : (it) In the stem there are a number of short spindles with rough warts. (/>) The spicules of the stalk are similar to the preceding luit are more numerous, and there also occur smooth, flat, striated spindles with few pro- tuberances, irregular three- and four-rayed forms, and si)indle- to star-shaped forms with toothed edges. Colour — Stalk, stem and lower part of branches, greyish-white ; upper part of smaller liranches and polyp-twigs, whitish to whitish-brown ; polyps brown. Locality : Station 78 ; off Ganjam Coast. 22 Dendronephthya kollikcri, var. andamanensis, Henrlerson. The colony is very large, measuring S-i:> cm. in height and 11 cm. in breadth. It is much flattened in one plane, and its branches have the appear- ance of portions of a whin-bush. The stalk or trunk is thick and .short, measuring almost 2 cm. in length, and has a broad base of attachment. It is granular in appearance. The polyparium is very large, much flattened, and consists of two principal branches, one of which divides into two. Below these are given off' the lower branches which are reflexed, flattened, leaf-like structures with broad bases which almost surround the stem, forming a collar to the upper ]jortion of the stalk. From the principal branches numerous smaller branches are given off, which by repeated division give rise to the polyp-bearing twigs. The whole polyparium is characterised by the great growth of the three prinei])al branches, by the profuse, irregularly arranged branches which rise from the whole surface of the stem and pi'incipal branches, by the large spicules which are arranged transversely, and by the large projecting spicules of the Stiitzbtindel. The polyps are arranged in small bundles of five to seven, which are placed on widely diverging stalks of about 1 mm. in length, at an angle which varies from right to obtuse. They occur singly on the edges of the flattened branches and either singly or in small groups on the upper surfaces. They are slightly oval in shape and average about O'O mm. in height and 0-78 mm. in breadth. The polyp-spicules are arranged in eight double rows in each of which there are three to Ave pairs of converging spicules, of which the uppermost pair is much longer and projects considerably beyond the polyp. The lower polyp-spicules average about 0'35 mm. in length, while the upper projecting spicule measures about 072 n)m. and may project 0-36 mm. lieyond the polyp. They are more or less straight spindles and have a number of blunt spines. The j^roject- ing spicule is more thickly covered with blunt spines, and on the projecting part the spines are directed obliquely towards the tip. The Stiitzbimdel is well developed and consists of several spicules, one of which measures 3"8 mm. in length and projects about 1 nun. beyond the polyp. Cortical s})icules : {(i) In the stem there are straight, curved or crooked spindles, short, broad spindles forked at one end, and a few globular bodies. All are covered with prominent rough warts regularly arranged on the surface. The spindles vary from 048 to 65 mm. in length and from 0'06 to 0-66 mm. in breadth. They are arranged transversely on the stem and principal branches, and more or less longitudinally on the siualler branches and twigs. (//) In the stalk tlmve are thick spindles, straight or curved, cylindrical rods, clubs, three- and four-rayed forms, rough globular forms, flattish, irregular forms which may or may not be branched, and irregular star.s. All bear 23 numerous regularly arranged, blunt warts wliich may be branched. The spindles vary from 033 to 18 mm. in length, and from 015 to 0:33 mm. in breadth; the rods vary in length from 0-i to 1 mm. The three- and four-rayed forms average aliout 0'{» nmi. in greatest length, the clubs about ()-5 mm. Many of the spindles are forked at one end, the prongs lying close together, or spreading apart and simulating three-rayed forms. There are also spindles which give off a short branch about the middle of their length, and others with prominent thorns and warts on the convex side. C'anal-wall spicules : (a) In the stem the spicules are similar to the spindles in the cortex of the stem and are covered with numerous regularly arranged, blunt, rough spines or simple warts, and vary from O'H to 3) In the stalk the spicules are similar to those of the cortex of the stalk but slightly larger and thicker. Colour — The stalk, stem and branches white with a tinge of red ; the smaller branches, twigs and polyp-stalks yellowish-red ; the polyps yellowish- white. Locality : Table Island (Cocos) Fig. 14. D. cocosiensis. — b, Spicules of stalk cortex ; c, Spicules of stalk canal walls. The smaller spindles average about Dendronephthya purpurea, Henderson. The specimen measures 6 cm. in height and about 47 cm. in maximum breadth. The stalk or trunk is short and flabby, greatly wrinkled and contracted. It is granular in appearance and gives off from its base a number of stolons. The polyparium is very irregular in shape, flattened on one side and rounded on the other ; it is fairly compact in the lower portion, but very open and 28 irregular in the upper, a few branches being more strongly developed than the others. From the lower part of the stem a large number of small branches are given off, and then the stem itself divides into two large branches which give off similar small Ijranches. These small branches by repeated divisions give rise to the polyp-bearing twigs. The polyps are arranged in small bundles of four to nine, and ai-e placed at an obtuse angle on widely divergent stalks, about 2 mm. long. They are oval, about 048 mm. high and 0-56 mm. broad. The spicules are arranged in eight double rows in each of which there are five to six pairs, one of each uppermost pair being much larger and projecting considerably. The lower polyp-spicules average 0-24 mm. in length, the upper projecting spicule about (J-aG mm. The spicules are thick spindles and have numerous warts which are less developed on the projecting part. On the aboral surface of each tentacle there are two rows of short rod-like spicules. Fig. 15.\. D. purpurea. — b, from stalk cortex ; c, from stalk canal walls. Fig. 15. D. purpurea. The .Stutzbundel consists of a number of large spicules of which several may reach a length of 3 mm. and one may project for a distance of 1 mm. beyond the polyp-head. Cortical spicules : {a) In the stem there are spindles curved or straight, four-rayed forms, four-rayed forms in which two of the rays are rei)resented by stumps, all with numerous very small regularly arranged spines. There are also smooth, flat, irregular three and four-rayed forms. Several of the spindles have a number of very short stumps arranged in a whorl at one end. The large spindles average about \'2 mm. in length, the small about 0"18 mm. Spindles of 1 6 mm. in length are present. The spicules are arranged more or less longi- tudinally. {Ji) In the stalk there are irregular stars, spindles with one whorl of large 29 spines at each end, small thick spindles, and numerous irregular forms, all with large simple or branched spines. There are in addition a few flat, smooth striated forms. Canal-wall spicules : (a) In the stem there are a very few minute disc-like ])(i(lies and a few smooth, flat, star to spindle-shaped forms. (Ij) In the stalk the canal-wall spicules are similar to the preceding. Colour — Stalk yellowish-white ; stem, branches and twigs deep purple- red ; polyps white. Locality : Andamans. Dendronephthya cervicornis (Wright and Studer) (= ,S. rhodosticta, Wright and Studer). To this species we refer a large specimen which measures about 8'5 cm. in height and 8"5 cm. in greatest breadth. In all essential details the specimen agrees with the description given of Spongodes rhodostkUi, Wright and Studer, rather than with the type D. cervi- coDtia, but there is no real distinction between these two. The colour of the present specimen is as follows : The whole colony, with the exception of the polyp-stalks, twigs and portions of the smaller branches, is white ; the polyps and polyp-stalks are brownish-red ; the twigs and tips of the smaller branches a light brownish-red. Locality : Station 291 ; Persian Gulf, 48-49 fathoms. To this species we refer another specimen which measures 8 cm. in height and 6 cm. in greatest width. It is slightly bush-shaped, and very open in ap- pearance, flatteneil in one plane, somewhat like a tree growing against a fence, with small branches going off in every direction, and owes its appearance to the unequal lengths of the branches. The texture of the main stem and branches is flabby. The colour of the species is somewhat varied. In the present specimen the stalk is brownish- white ; the stem and principal branches yellowish-white with here and there dark red streaks appearing on the surface ; the smaller branches, twigs and polyi)s orange-red ; the polyp-tentacles white. In the original example the colour is white, the twigs and polyps of the lower half of the polyparium purple. In the specimen described by Hickson and Hiles the colour of the main stem, branches and polyp-heads is whitish, of the twigs purple. Whitelegge's specimen was, on the other hand, yellowish-white in colour, the twigs and polyps appearing red. Locality : Table Island (Cocos), Andamans. The species is previously recorded from Tahiti, "iO-OO fathoms ; Sandal Bay (Lifu) ; Funafuti, 20 fathoms ; Kei Islands, 140 fathoms ; and Talili Bay (New Britain). 30 Dendronephthya orientalis, Henderson. A large specimen, compact in appearance and much flattened, measuring 11 cm. in length and 7 "5 cm. in breadth. Fig. 16. D. orientalis. Fig. 17. D. orieutalis. — b, Spicules of stalk coi'- tex ; c. Spicules of stalk canal walls. The stalk or trunk is short, tiiick, granular in ai)i)earance and leathery in texture, measuring 3 "5 cm. in length, almost one-third of the total height, and furnished at the basal end with short stumps which may be the remains of stolons. The polyparium is large, much flattened, somewhat regular in shape and roughly oval in outline. One side of the polyparium is flat and thickly covered with branches and polyps, while the other side is slightly rounded and more open. From the lower ])art of the main stem a number of small branches are given off; a little higher the stem gives off two large cylindrical branches, then rises entire for a considerable height, when it divides into two portions which are short and cylindrical in shape. From the whole surface of the main stem and branches smaller branches arise, and by divisions give rise to the twigs from which the polyp-stalks spring. These branches are on the whole cylindrical in shai)e in the lower part, often flattening a little at the point of division and u'iving ofl' flattish smaller branches or twigs which lie more or less in one plane ; or the lower part may be considerably flattened and the upi)er twigs branch in a plane which lies almost at a right angle to the lower portion. The lower branches, two in number, are flattened leaf-like structures ; one is much larger than the other, and the two with their broad bases almost sui-round the stem, and being reflexed, form a collar hiding the upper portion of the stalk. From the upper surface of these branches smaller cylindrical branches arise. One of these arising from the larger flattened branch reaches considerable pro- portions. The main stem itself in its lower part is somewhat flattened in the plane of the polyparium. The polyps are almost all on the surface, arranged in small bundles of 31 four to twelve imlividnals. They are placed at an angle which is usually right, but may be obtuse, on fairly long stalks, which may measure up to 2'.i mm. in length, but which on an average are considerably shorter. The groups on the lower part of the polyparium show a marked tendency to the divaricate ty])e, but in the upper pait they stand more closely together. On the edges and upper surface of the flattened lower bi-anches the polyps occur singly or in small groups. The heads are rather large, being 0"9 nnii. high and 0"65 mm. broad. The polyp-spicules are arranged in the following manner ; the lower spicules, which measure from 0'33 to 051 mm. in length, are placed horizontally, above them rise eight pairs of large spicules which run practically parallel, being bent near the proximal end, the bent parts diverging ; one of the pair is invariably larger than the other and projects further beyond the polyp, the smaller being often replaced by two still smaller spicules. In the spaces between adjacent pairs one or two small spicules are present, which in certain stages of the polyp's contraction or expansion may be ])arallel to the diverging parts of the large spicules. The latter measure from 0'48 to 0"9 mm. in length and may project to half their length beyond the polyp-head. The polyp-spicules are spindles, either straight or curved, and covered with regularly arranged blunt spines or thorns. On the aboral surface of the tentacles there are two rows of flattish toothed spicules, the ends of the spicules of the two rows interlacing in an irregularly alternate manner. The Stutzbtindel is well developed, and contains several large spicules, one of which may measure 2"5 mm. in length, and project for a distance of 11 mm. Very frequently the tip of a second projects for a short distance. It is of interest to note the different stages in the growth of the Stiitzbtindel, for in many of the smaller polyps it seems to be absent. Cortical spicules : {ft) In the main stem and branches there are spindles, straight or curved and covered with numerous blunt spines, regularly arranged. They vary in length from 042 to 25 mm. and in breadth from 0072 to 018 mm. In addition there is a corresponding series of flatter spicules, much smaller in size and with fewer spines. In the principal stem and branches the spicules are arranged so as to produce a granular appearance, which gives way to a transverse stringy appearance only towards the tips, but in the smaller branches there is a distinct irregular meshwork of spicules arranged obliquely and trans- versely, and this continues up into the twigs. (h) The stalk contains thick spindles, rods, ovals, clubs, triangles, globular and roughly four-sided forms, and a series of irregular spindle- to star-shapes. All except the last series are covered with numerous rough or branched warts, somewhat regularly arranged. The last series have equally prominent rough warts, but fewer in number and less regularly arranged. Many of the spindles are curved and show a greater development of warts on the convex side, and 32 many of the ovals and four-sided forms send out irregular somewhat flattened branches which may again branch. Some measurements are : Spindles 1'2 mm. X 024 nmi. ; rods 0'48 mm. x O'lo mm. ; clubs 042 mm. x 0'21 mm. ; ovals up to 06 mm. x 03 mm. Canal-wall spicules : (a) In the stem ai'e short, thick si)in(lles, thickly covered with regularly arranged rough warts and measuring up to IS mm. x 0"3 mm. ; also a few small globular forms with fewer and less rough warts. {/>) Those of the stalk may be divided into two series, a rough and a smooth — the rough similar to the stalk cortical spicules, spindles, clubs, ovals, etc., the spindles measuring up to 08 mm. x 018 mm. — the smooth series containing irregular, flat spindles, measuring 0"42 mm. x 012 mm., irregular flat three- and four-rayed forms, oval and triangular forms, all of which may be greatly branched. Colour — Stalk and principal branches dark Iirownish-grey ; stem and smaller branches a lighter shade of the same ; polyp-stalks and polyps reddish- brown ; tentacles greyish. Locality : Andamans Coast, 13 fathoms. Dendronephthya arbuscula, Henderson. The colony is large, somewhat bush-shaped, mostly developed in one plane, with a long stalk, and measures 11 cm. in length and 8 5 cm. in maximum breadth. Piij. 19. D. arbuscula. — From stalk cortex. Fig. 18. D. arbuscula. The stalk or trunk is long and rigid, granular in appearance, leathery in texture, measuring about 5"6 cm. in length, and having its upper part covered by the reflexed lower branches. The polyparium is large, much flattened, with no regular outline owing to the arrangement of the principal branches. From the lower part of the stem 33 a number of smaller branches are given off. Immediately above this the stem gives off three main branches, one of w^hich rises partly from the upper surface of one of the lower Hattened branches ; then it continues straight upwards for a considerable distance giving off only a short thick branch at one side. All the princii)al branches are thick and cylindrical in shape and give off from their surface a number of smaller branches, which directly, or by one or two divisions, give rise to the polyp-bearing twigs. The lower branches are flattened leaf- like structures which surround the stem, forming a sort of collar and hiding the upper part of the stalk. Two of them almost completely surround the stem, leaving only two small free spaces, and have their edges much convoluted, the free lateral surfaces curling upward towards the apex of the colony, thus forming a sort of triangular space over the free spaces. In these free spaces at a slightly lower level two smaller branches arise with cylindrical stalk and flattened upper portion which corresponds to the triangular space and is spread out in umbrella-like fashion. The polyps are arranged, somewhat loosely, in small bundles of three to eight ; the divergence of the polyps of a bundle is seen more markedly on the lower part of the polyparium. From the edge and from the upper surface of the flattened lower branches the polyps arise singly, or in small groups from twigs. The heads are small, measuring 0-54 mm. in height by 048 mm. in average breadth, and are placed on stalks of about 2 mm. in length at an angle which is usually obtuse. The spicules are arranged in eight double rows, in each of which there are five pairs of converging spicules ; the uppermost pair are much longer than the others, run almost parallel, and project beyond the polyp- head. The lower spicules measure on an avei'age 018 mm. in length, wliile the upper have an average length of 0'36 mm. and project 018 mm. On some of the younger polyps the difference between the upper and lower polyp-spicules is not so marked and the projection is not so apparent. On the aboral surface of the tentacles there are two rows of almost transversely placed, flat, toothed spicules which are thickly crowded together. The Stutzbundel is well developed, one of the spicules may reach a length of I'o mm. and project for a distance of 0-36 mm. ; usually the tip of a second, and sometimes that of a third, may be seen projecting. Various stages in development can be seen, from cases where the .Stiitzbiindel is represented by a slightly larger sjjicule up to the complete form. Cortical spicules : {a) The spicules of the stem and main branches are placed transversely, those of the smaller branches and twigs obliquely trans- versely or longitudinally. They are large spindles, straight or curved, and thickly covered with regularly arranged blunt to roughish spines. Several show bifurcation at the end. They vary in length from 0-33 to 34 mm. and in breadth from 006 to 024 mm. 5 34 (b) The stalk contains thick spindles, clubs, ovals, irregular three- and four- rayed forms, irregular three- and four-sided forms with sides slightly concave. All these are covered by prominent very rough warts more or less regularly arranged ; the spindles are often much bent and sometimes show short branch- ings. Spindles measure up to 12 mm. x 030 mm.; three-sided forms, 0'42 mm. X 0'36 mm. ; four-rayed, 054 mm. x 030 ; clubs, up to 0'54 mm. x 0"24 mm. ; these often show a ridge of very prominent fused spines or warts on one edge. In addition to these there are a number of similar forms with few, and on the whole, sinn)ler warts. Canal-wall si)icules : {a) The stem contains long slender spindles with regularly arranged blunt spines. They measure up to 2"4 mm. in length, and from 015 to 039 mm. in thickness. (f)) Those of the stalk include large, thick spindles, usually curved ; three- and four-rayed forms with long, thick rays ; three- and four-rayed forms with a short ray rising at an angle to the plane of the other two or three ; tripod forms with a fourth ray at right angles to the other three ; and small oval to globular forms. All these are thickly covered with prominent very rough warts which are usually branched. There is also a smoother series, with fewer and simpler warts, which vary from spindles to four-rayed forms. Spindles measure up to 2"2 mm. x 0"42 mm. ; three-rayed forms up to 17 mm. x 1-2 mm. ; four-rayed forms up to TS mm. x 1-3 mm. The rays of the three- and four- rayed forms are wider at the ends and may have a thickness of 042 mm. Colour — Stalk dirty white ; stem and branches greyish-white ; twigs reddisli-])ink ; polyp-stalks, varying from reddish-pink in lower part to yellow in upper part of the polyparium ; polyps yellow. Locality ; Andamans. Dendronephthya costatorubra, Henderson. The colony is distinctly divaricate in ty]»e and is evidently a young specimen, measuring 30 mm. in height and 23 mm. in maximum breadth. The stalk or trunk is slender and by no means rigid ; it measures 13 mm., about half of the total height of the colony, and is characterised by its white semi-transparent ap) )earance. The polyparium is small, much flattened, and of no regular outline. It is formed of a mimber of branches which rise at an angle of about 45" to the main stem. Below these arise three flattened leaf-like branches or folds, which form a collar round the u]iper part of the stalk, leaving only three small open spaces two of which are opposite each other ; directly below these two, two smaller branches arise, which have a cylindrical stem and a flattened upper ]iortion, somewhat umbrella-sha])etl with the concave surface uppermost. 35 The polyps are arranged on elongated, diverging stalks in groups of four to five, young polyps arising often in the angle between two older polyp-stalks. They also occur singly on the edges of the lower branches They are small. Fig. 20. D. costato- rubra. Fig. 20a. D. costato- rubra. — b, from stem cortex ; c, from stem canal walls. the length averaging 0-48 mm. and the breadth 0-6 mm. They are placed on the stalk at an obtuse angle, which often approaches very nearly to a right angle. They are roundish oval in shape, the long axis being parallel to the stalk. The younger polyps are much smaller on an average, measuring 27 mm. in length and 03 mm. in breadth. The spicules are arranged in eight double rows, in each of which there are four to five pairs of converging spicules. It is the exception for any of these to project beyond the polyp-head, but in one or two cases the uppermost project a very little. The spicules of the lateral rows are occasionally a little larger, but seldom project at all. The polyp- spicules are somewhat flattened spindles, straight or slightly curved, with simple spines ; they often measure about 0'36 mm. in length, but are usually smaller. The Stutzbundel is well developed, consisting of two to three large, and a number of smaller spicules. One of the larger projects considerably, and very often a second also projects. In younger polyps the Stiitzbiindel is not so pronounced but still is (juite distinct, while in the youngest polyps its presence can be detected only from the fact that spicules are more numerous on the dorsal side of the short polyp-stalk. Cortical spicules : (a) Those of the stem are slender spindles, straight or curved, 06 to i^ mm. long, 003 to 015 mm. thick. They form an irregular mesh-work, the smaller spicules lying in the larger meshes or running from one mesh to another. This arrangement is marked out by the presence of spicules either pink in colour or with a pinkish core. (b) Those of the stalk are large spindles straight or curved, clubs, three- 36 and irregular four-rayed and rough star-shaped forms. They are all furnished with large prominent thorns, simple or compound. There are also short, curved spindles with huge thorns on the convex side, and irregular stars with few spines. The spindles may reach a length of 24 mm. and a breadth of 015 mm. The spicules are so arranged on the stalk as to produce a stringy appearance. Canal-wall spicules : {a) In the stem there are a few small curved spindles, 0"27 mm. long and 0024 mm. thick, and flat star- to spindle-shaped forms. (b) The stalk has spindles, straight or curved, and often showing bifurca- tion at one end, three-rayed and a few four-rayed and irregular forms, some of which might be called incipient clubs. The spindles measure up to 103 mm. in length by 0"15 mm. in breadth. Colour — Stalk white ; stem yellowish-white marked with pink ; terminal branches and twigs pinkish ; the polyps appear red owing to their spicule colour. Locality : Andamans. Dendronephthya macrocaulis, Henderson. This species is based on two specimens, in the larger of which the stalk is absent, and in the smaller the stalk is very short. The polyparium of the larger measures about 6 cm. in height and 6'5 cm. in gi'eatest breadth. The stalk was apparently short and had its upper portion hidden by the rettexed lower branches. In the smaller specimen it is granular in appearance. The polyparium is markedly flattened, irregular in outline and very loose and open, and is char- acterised by the enormously long polyp-stalks, which average a little over 5 mm. in length and often reach 8 mm. It consists of a number of principal branches each of which gives oft' other large branches which finally give rise to the polyp-bearing twigs. The prin- Fig. 21. D. macrocauUs. ^jp^j branches are flattened in the plane of the polyparium, and give off' from all sides small branches which 37 give rise to the polyp-bearing twigs. The lower branches are flattened, leaf- like structures, two of which almost surround the stem. Below these there are a number of smaller branches with cylindrical lower and flattened upper portions. A majority of the smaller branches also show a slight flattening where they break uj) into the polyp-bearing twigs. The polyps are arranged in small groups of three to five on widely divei'gent stalks, and also occiu' singly or in smaller groups on the edges of the large flattened branches. They are high, measuring about 1-2 mm. in height and 09 mm. in breadth, double cone-.shaped and attached to the long (over 5 mm.) stalks by the apex of a cone. They sit at an angle which is very variable but approaches an obtuse angle, and the upper cone is incomplete. The spicules are arranged in the following manner : On the lower part there are a number of spicules ari'anged obliquely transversely, of which a few are strong, stout thorny spindles. Then there is a ring of horizontally placed spicules three to four deep, and above this rise eight points each consisting of one pair of converg- ing spicules which are much larger than the lower polyp-spicules and project for a variable distance according to the state of retraction of the polyp. In the space between adjacent points a small spicule is always present, which lies more or less parallel to the larger spicules of the point. The lower polyp- spicules average about 35 mm. in length, the upper about 64 mm. On the aboral surface of each tentacle there are two rows of small rod-like spicules. The Stiitzbundel is well developed, and consists of a number of spicules, two or three of which always project beyond the polyp. The spicules may reach a length of 2 '4 mm. Cortical spicules : {«) In the stem the spicules are long, slender spindles, either curved or straight and bearing numerous regularly arranged inconspicuous spines. The larger average about 37 mm. in length. {h) In the stalk there are spindles, clubs and numerous irregular star- shaped forms, all having very prominent spines on the surface. The spindles average about 0") In the stalk the spicules are similar to those of the canal walls of the stem with the doubtful addition of a very few small ordinary spindles. Colour — The stalk, stem and branches are white to semi-transparent ; the twigs and polyp-stalks orange-yellow ; the polyps white. Locality : Andamans. The smallest specimen has two flattened, leaf-like branches which are reflexed and form a collar, and the polyparium is greatly flattened. This specimen agrees in all essential details with the two larger and is evidently a young specimen. This new species belongs to the rigida group and is not far removed from D. rosea. Dendronephthya foliata, Henderson. The colony is divaricate and presents a beautiful regular oval outline, the principal branches being of about the same size. It is 7 cm. high and 6 5 cm. broad. 52 The stalk is thick and fairly rigid, measuring 27 cm. in length and giving oif a number of short stolons at the base. The polyparium is large, much flattened, regularly oval, and presents a very compact appearance owing to the numerous small branches wliich raise all polyps more or less to the surface. It is further characterised by the great development of flattened bi-anches at its lower end. At the upper end of the stalk two large flattened leaf-shaped branches or folds almost surround the stem, forming a collar to the upper part of the stalk and leaving only two small open spaces. They are very long, and the ends of the folds are curved upwards towards the apex of the colony. In the angle between them a smaller branch arises with cylindrical stalk and a flat- tened, three-cornered upper portion which stands at right angles to its stalk, the beautiful correspondence between its free edges and those of the larger neigh- bouring branches giving it an appearance somewhat like that of a bone suture. Above the small space on one side an- other flattened branch arises, but it is reduced to a small narrow band, for directly above it two other flattened branches arise which come into contact almost above the middle of it. On the other side the single flattened branch is absent, there being only the two similar upper ones. Above this numerous branches are given off', filling out the regular oval. The polyps are arranged in small groups, commonly of seven individuals, but occasionally groups of four and also of nine are found. On the edges and upper surface of the lower flattened branches they occur singly or in small groups of four to five. The polyps, which are placed at an olituse angle on a stalk measuring about lo mm., are low, egg-shaped bodies, slightly flattened, with an average height of 048 mm. and a breadth of 0"72 mm., the greatest breadth being dorso-ventral. The spicules are arranged in eight double rows, in each of which there are four to five pairs of converging spicules ; the upper- most pair are of unequal size, the larger projecting 43eyond the polyp for a considerable distance. The spicules are flattened spindles, either straight or curved, with simple spines, which on the projecting part of the longest spicules are directed towards the tip. The lower spicules average 0"33 mm. in length, while the projecting spicules may reach a length of 072 mm. and may project for a distance of 0'39 mm. Fig. 27. D. foliata 53 The Stiitzl)iind('l is well developed ; it consists of several spicules one of which may be 4(3 mm. long and project 1 mm. beyond the polyp. The tip of a second may also project slightly. Different stages can be well seen in polyps of different sizes. In the younger, the Stiitzbiindel spicules are not very dif- ferent from the others in size but their arrangement at once distinguishes them. Cortical spicules : {n) Those of the stem are large spindles, either straight or curved, and one or two forms of spindles which have a thick part in the middle, then are abruptly narrowed and produced into a long, thin, tapering point. All are covered with regulai-ly arranged spines or thorns which are simple in the smaller, but tend to become wart-like in the larger spicules. They vary from 0-36 to 5-0 mm. in length, and from 005 to 027 mm. in breadth. On the smaller the number of spines is relatively less than on the larger. (/>) The stalk contains short, thick spindles, thick clubs, globular forms, T-, Y- and L-shaped forms, irregular short spindles, and half-moon shaped forms, four-rayed forms, spindles with a short branch on one side, and balls with two arms going out at one side. All are characterised by the great develop- ment of the large warty protuberances which are on the whole regularly arranged. Spindles measure up to 20 x 0*25 mm., clubs up to 09 x 027 mm., globular forms up to 0"265 mm. The arrangement of the spicules on the stalk presents a fine granular appearance. Canal-wall spicules : {/() The stem contains straight or curved spindles which may measure IS mm. in length and 024 mm. in breadth and are covered with warty protuberances, and small, flat, smooth, spindle-shaped to star- shaped forms. (/>) The stalk contains very thick spindles, clubs, three-, four- and five-rayed forms, spindles which give off from one end three or four rays, peculiar hunch- backed spindles, and small, flat, smooth stars. All except the last-named are covered with prominent, regularly arranged, multituberculate warts. Spindles measure up to 21 mm. in length by 042 mm. in breadth, and some of the three-rayed forms measure 2"5 mm. in greatest length. In many of the four- rayed type one half is exactly the mirror image of the other half. Colour— Stalk, stem and branches whitish-yellow ; upper surface of flattened branches white ; tips of the twigs, polyp-stalks, polyp bodies pale violet ; tentacles white. Locality : Andamans. Dendronephthya pentagona, Henderson. To this species we refer a specimen from the Andamans, which measures about 6 cm. in height and about 5 cm. in greatest breadth. The stalk is stiff and parchment-like in texture and measures about 2-5 54 cm. in total length. It is granular in appearance and shows traces of a few stolons at the base. The polypariiim is greatly flattened in one plane, roughly pentagonal in outline, and practically entire, showing no breaks on the surface. It consists of four principal branches which all lie in the same plane, two near the base of the stem, and the other two just at the tip. All over the main stem and branches smaller liranches are given off", which by repeated division give rise to the polyp-bearing twigs, a slight tiattening being occasionally seen at the point of division. Two of the lowest branches are flattened, leaf-like structures which almost surround the stem, leaving only two small free spaces, in each of which there is a small branch with a cylindrical lower part and a triangular flattened up})er part concave above. The polyps are arranged in groups of four to eight, and occur also in small groups or singly on the edges of the flattened branches. They are i-ound in shape and average 072 mm. in height and 072 mm. in breadth, and are placed at an angle which varies from right to obtuse on stalks of about ] mm. in length. The polyp-spicules are arranged in eight double rows, each of five pairs of converging spicules, of which the uppermost pair are longest and project beyond the polyp. The lower polyp-spicules average about 0'24 mm. in length, the upper projecting spicules about 0-56 mm. On the aboral surface of the ten- tacles there are two rows of small rod-like spicules. The Stiitzbiindel is well developed, one of its spicules may reach a length of 3-2 mm. and project for a considerable distance beyond the polyp. Cortical spicules ; (n) In the stem there are numerous spindles either curved or straight with numerous blunt spines on the surface. They may be divided into two groups, the smaller averaging about OS mm. in length, the larger about 2 mm. (fj) In the stalk there are spindles, clubs, three- and four-rayed forms and numerous irregular globular forms, all of which bear numerous regularly arranged prominent rough warts. There are in addition a number of forms which vary from flattened spindles to discs, and some roughly triangular flat plates which show a marked striation on the sui'face and are entirely free from warts or spines of any description. The spindles average about 1 4 mm. in length. Fig. 28. D. pentagona. 55 Canal-wall spicules : (a) In the stem the spicules are similar to the spicules of the cortex of the stalk, but differ in having fewer rough warts. The si)indles average about 1 -J nun. in length and 0'2S mm. in breadth. (//) In the stalk the spicules are similar to those of the canal walls of the stem, and in addition there are numerous spindles, three- and four-rayed forms, discs and plate-shaped spicules which are very flat, show a striated surface, and bear few or no spines. The stalk canal-wall spicules show every phase between blunt spines and simple warts. Colour— The stalk, stem and branches are white ; the twigs and polyp-stalks yellowish-white to l)rownish-red, white on the flattened lower branches ; the polyps white. Locality : Andamans. Dendronephthya merguiensis, Henderson. The colony is small, measuring about 4o cm. in height and about 3 cm. in maximum width, much flattened, oval in outline, delicate in appearance. The stalk is 1 -8 cm. in height, nearly one- half of the total. It is very delicate but somewhat rigid, stringy in appearance. It gives off at its lower end a number of slender stolons and has its upper portion partly hidden by the reflexed lower branches. The polyparium is much flattened and of regular oval outline, the long axis of the oval and that of the stem corresponding. From the lower end of the stem a number of small bi'anches are given off, then two larger branches are given off almost at right angles a little above this, at slightly different levels on opposite sides of the stem and in the same plane. There is no more branching until a little below the apex of the colony, where the stem divides into two main portions which diverge so as to form almost a right angle between them. All these branches are cylindrical in form, and from their surface and the whole stem surface smaller branches are given off which by dividing once, or by repeated divisions, give rise to the short, thick twigs on which the polyps are borne. The lower branches are flattened, leaf-like structures which are reflexed and almost surround the stalk, in collar-like fashion, leaving two small free spaces ; above each of these rises a small branch which shows a slight flattening. Fig. 29. D. merguiensis. 56 The polyps stand in small groups of six individuals on short stalks, the longest stalk measuring about 1 mm. in length. The individuals of a bundle do not diverge very much. The polyps are somevrhat flat, measuring on an average 072 mm. in height and 078 mm. in breadth. They are placed at an obtuse angle on the stalk. The polyp-spicules are arranged in the following manner : Two to three pairs of spicules may meet at an angle or be practically horizontal, then above these one pair of converging spicules arises, one of which is larger than the other and projects beyond the polyp. Between adjacent pairs but always near the smaller of the two spicules lies another spicule of about half the size. The polyp-spicules are spindles with few simple spines, and measure O'SO mm. in average length, the longer of the up})ermost pair reaching 0'42 mm. and projecting 0'12 mm. Closely packed together on the aboral surface of the tentacles are two rows of flat, toothed spicules. The Stiitzbiindel is well developed ; one spicule may reach a length of 3 "3 mm. and may project 072 mm. beyond the polyp, but usually it is not so pronounced. Cortical spicules : (n) The stem contains long, slender spindles, either straight or slightly curved, and sparsely covered by small spines regularly arranged. They measure from 0'9 to 24 mm. in length and from 006 to 015 mm. in thickness. They are more or less regularly transverse in posi- tion on the stem and main branches. (fi) Those of the stalk are slender spindles with prominent blunt warts, and smaller, smoother, irregulai* spindles. They measure on an average 1 mm. in length and 01 2 mm. in thickness. Canal-wall sj^icviles : {a) The stem has spindles, usually straight or slightly curved, stringy in appearance, and practically without protuberances. They average 0*42 mm. in length. There are also smooth, flat spindle- to star- shaped forms. (b) Those of the stalk are similar to those of the stem, and in addition there occur a few three-rayed forms. The spindles differ, however, in having more numerous and more prominent spine-like protuberances, and average about 072 mm. in length. Colour — The colony generally is white ; exceptions are, polyp-spicules, tips of the twigs, and little patches here and there on the edges of the flattened branches, which are pale lilac, while a more distinct tinge of the same is seen in the polyp-stalks. Locality : Forrest Strait, Mergui Archipelago. Dendronephthya crystallina, Henderson. The specimen is pear-shaped, regular in outline and somewhat flattened in one plane. It measures 43 cm. in height and 3-9 cm. in maximum width. 57 Fig. 30. D. crystallina. The stalk is short, and the long axis of the polyp-bearing portion stands at an angle to the stalk. The stalk is short, measuring 1'2 cm. in length, somewhat thick and rigid, and gives off fi'om its base and for a short distance up the side numerous stolons to which are attached frag- ments of shells and grains of sand. The polyparium is pear-shaped and slightly flattened in one plane, and consists of a number of branches which rise almost at a right angle to the stem. The stem rises for a short dis- tance entire, and then gives off a large branch on each side in the plane of flattening. Slightly farther up it gives off a second large branch on one side also in the plane of flattening. The larger branches rise at an angle which approaches a right angle, and give rise by repeated divisions to the small twigs which bear the polyps. Over the surface of the stem and branches smaller branches arise, which either bear the polyps themselves or give rise by division to the polyp-bearing twigs. Two of the lowest branches are leaf-like, flattened and reflexed, and almost surround the stalk, leaving two open spaces between the edges of their base of attachment, in which small ordinary branches with a rounded stem are found. The polyps are arranged in small groups of five to six, two or three of these being grouped together to form larger bundles. On the edge of the flattened, leaf-like branches the polyps occur singly or in small groups. The polyps are low, shallow, cup-shaped, measuring 0'4 mm. in height and 064 mm. in breadth. Each polyp sits at a right angle on a stalk which measures on an average 08 mm. in length. The polyi)-spicules are arranged in eight double rows, in each of which there are five pairs of converging spicules. The upper pair in each row projects for a short distance beyond the polyp, and in the space between the double rows there are one or two pairs of short, thick spicules which run parallel to the sides of the adjacent double rows. The spicules are flattened spindles, either curved or straight, with minute spines on their surface. They measure on an average 024 mm. in length and 0032 mm. in breadth ; the projecting spicules, however, may reach a length of 0'4 mm. On the aboral surface of each tentacle there are two rows of small, flat, blunt spicules, arranged in bluntly converging pairs with their apices directed towards the distal end of the tentacles. The Stiitzbundel is well developed, and consists of a number of large spicules which form a support for the polyp-stalk. The spicules may reach a 58 length of 2"8 mm. and one may project for a distance of IB mm. beyond the polyp-head. Cortical spicules : (a) In the stem the spicules are curved or straight spindles which often divide at one end into two or three branches or prongs which usually lie in close contact throughout their length. They are trans- parent, but the majority have a central axis of various shades of light-brown to brownish-i)ink. They measure up to 24 mm. in length and 0"1(3 mm. in breadth. (b) In the stalk sjDindles, three- and four-rayed forms and numerous irregu- lar forms are present, all of which are thickly covered by simple or branched spines. The spindles are either straight or curved and have the spines specially developed on one side, either running the whole length of the s})icule or con- fined to a short tract on the side. They measure up to 136 mm. in length and 0"14 mm. in breadth, of which 01)*J4 mm. represents the length of the spines. The three- and four-rayed forms have in the centre an X-shaped marking. On the rays there are numerous large spines and in several cases one ray is more or less rudimentary. Canal-wall spicules : (a) The spicules of the stem are represented by a very few small simple rods and three-rayed forms, and in addition by numerous small disc-like bodies. The rods measure up to 0'1(3 mm. in length and 0"0075 mm. in breadth. {/)) In the stalk the spicules are represented by numerous small disc-like bodies. Colour — The stalk, stem and lower parts of the primary branches are translucent ; the upper parts of the branches, twigs and polyps are purple ; the tentacles translucent. Locality ; Unknown ; Marine Survey. Dendronephthya andamanensis, Henderson. This species is represented by a single specimen which measures 5-5 cm. in height and 3 "8 cm. in breadth. The exact shape of the polyp-bearing portion cannot be accurately determined, as the tips of the two upper branches are wanting. The sterile stalk is long, 4 cm. in length, faii'ly thick and rigid, and gives off from its base a few slender stolons, and also one or two at a distance of 1"5 cm. from the base. The polyparium is flattened and oval in form. From the lower part of the stem a few flattened branches are given oft', and then the stem divides immediately into three cylindrical main jjortions, or rather gives off partly from its lower portion and partly from the upper surface of the flattened branches two main branches and then bends slightly to one side itself. From the surface 59 of the priiK'iiial branches, smaller cylindi-ical Itranches are given off which by division give rise to the polyp-liearing twigs. Two of the lower branches are flattened, leaf-like structures, one of which, much larger than the other, almost surrounds the stem with its broad base, while the other with its smaller base fills up the remaining space, leaving only two small free spaces between its edges and the edges of the other. They are reflexed and form a collar to the upper part of the stalk. The polyps are arranged in small groups of four to eight on widely divergent stalks, and singly or in small groups on the edges of the flattened branches. They are low and oval in shape, and are placed at a right angle on the stalks (2 mm. long), and average 0-5o mm. in height and 0-(5(} mm. in breadth. The polyp-spicules are arranged in the following manner : The lower polyp-spicules are either arranged horizon- tally, or there are three pairs of spicules which meet at an obtuse angle ; then a ring of horizontally placed spicules three deep ; surmounting this are eight points, each consisting of two or three converging spicules which project beyond the polyp. (3f these converg- ing spicules one is much larger than the other, or others, for it is often opposed by two. In the space between the adjacent points there lie two smaller spicules of about 015 mm. in length which are parallel to the converging spicules, one lying usually close beside the larger projectnig spicule. The lower polyp-spicules average 0'33 mm. in length, the upper con- verging spicules measure about 0'45 mm. and project from 0*24 to 0'3 mm. beyond the polyp. On the aboral surface of each tentacle there are two rows of small rod-like spicules. The Stiitzbiindel is well developed, and has one oi" two .spicules projecting beyond the polyp, and sometimes the tip of a third may also be seen. These spicules measure aliout 2'8 mm. in length and project for a distance of (J"84 mm. Often the Stiitzbiindel is not so well developed, but this is undoubtedly a younger stage. The arrangement of the spicules on the polyp-stalks is worthy of notice. Along the ventral side there is a dividing line, and from this the spicules are regularly arranged obliquely and transversely, sloping towards the tip on each side. Cortical spicules : (a) In the stem there are long spindles with numerous regularly arranged rough warts. They are either straight or curved, often with a bifurcation at one end, and vary from 0'42 to 3'0 mm. in length and Fig. 31. D. andamanensis. 60 from 0"04 to 021 mm. in breadth. There are also some smaller spindles with very few and simple thorns. (b) In the stalk there are long, curved or straight spindles with very regularly arranged prominent and often branched warts. They sometimes give ort' a short branch about the middle of one side, and vary in length from 03 to '24: mm. and in breadth from 0'12 to 0-21 mm. Canal-wall spicules : (a) In the canal walls of the stem there are spindles with numerous regularly arranged prominent warts on their surfaces. They vary in length from 09 to 1"2 mm. and average about Olo mm. in breadth. In addition there are a few spindles, stringy or pitted in appearance, with few protuberances or none, and averaging about 27 mm. in length and 03 mm. in breadth. {/>) In the stalk there are curved or straight spindles, with numerous more or less regularly arranged branched warts on the surface, a few clubs and a number of iri'egular star-shaped forms, all bearing rough warts similar to those on the spindles. In addition there are flat, smooth spindle-shaped to star-shaped forms. The spindles average about 1 mm. in length and 0"15 mm. in breadth. Colour — The stalk is yellowish in its lower portion, yellow-white above ; the stem and principal branches white with a tinge of yellow ; the smaller branches and twigs yellowish : the polyp-stalks and polyp-spicules rose-coloured ; the tentacles white. Locality ; Andamans. Dendronephthya persica, Henderson. The specimen is large, measuring (3 cm. in height and almost 5 cm. in maximum width. The stalk is short and the polyp-bearing portion is greatly flattened in one plane and fairly compact in appearance. The stalk or trunk is about 1 cm. in length, and has its upper portion hidden by the reflexed flattened branches. It is thick and nuich wrinkled and has a flat base of attachment from the edges of which a few stolons are given off. The polyparium is regularly oval in outline, compact in appearance, and consists of a number of branches of about equal length. From the lower part of the stem a few small branches are given off, and then above this two branches are given off' in the same plane, at slightly different levels on opposite sides of the stem. Of these branches one is much larger than the other, and above their origin there is no division of the stem into main branches. The lower branches are flattened, fold-like or leaf-like structures, two of them being much larger than the rest, and almost surrounding the stem, leaving only a small free space between the edges. In the free space on one side two small 61 branches with cylindrical lower portion and flattened umbrella-like upper portion arise and fill up the si)ace ; in the other free space there is only a single branch similar to these two. From the upper surface of the flattened folds and partly from the stem there arise two cylindrical branches which stand at an acute angle to the stem, and are of considerable size. From the surface of the stem and larger branches smaller branches are given off at right angles to the surface ; these are cylindrical^ and by repeated divisions give rise to the polyp-bearing twigs. At the point of their first division a slight flattening occurs, and in most cases this is continued throughout all the divisions. The polyps are arranged in small groups of four to eight, and stand on stalks which measure up to '1 mm. in length. They are more or less divergent, but this is partly concealed by the young polyps, and thus the arrangement ap- proaches that of the TJttibcUaUe. On the edge of the flattened branches the polyps occur singly or in small groups. They are low and rounded, measuring 0'48 mm. in height and 0'7"2 mm. in Ijreadth, and are placed at right angles to the stalk, but at times seem to be at an acute angle owing to the head being slightly more bent down. The spicules are arranged in the following manner : about two pairs of polyp-spicules converge, then comes a girdle of horizontally placed spicules three to four deep, and above this rise eight points each con- sisting of one pair of acutely converging spicules which are unequal in length, and project for a considerable distance beyond the polyp. A third spicule is often present and lies usually parallel to the smaller of the two. The two projecting si)icules run almost parallel, diverging only near their base where they are sharply bent, and in the space thus foiined between their bent portions and the horizontally placed spicules, there may be a small curved spicule with the convex side upwards. Another spicule occurs in the spaces between the points. The lower polyp-spicules measure about 0"25 mm. in length, while the upper projecting spicules average about 0"6 mm. in length. On the spicules numerous thick blunt spines occur at right angles to the surface, but on the projecting portion of the spicule they are directed obliquely towards the tip. On the aboral surface of each tentacle two rows of densely crowded flattened toothed spicules are present. Fig. 32. D. persica. 62 The Stiitzbiindel is markedly developed, the larger projecting spicule giving the colony a spiny appearance, and making it decidedly prickly to the touch. The spicule may reach a length of 4'8 mm. and project for a distance of 1"2 mm. beyond the polyp. Cortical spicules : {i/) In the stem the spicules are arranged transversely, but become longitudinal in the smaller branches and twigs. They are spindles either curved or straight, and closely covered by regularly arranged rough warts ; they vary from 06 to 2"7 mm. in length and from 006 to 0'36 mm. in breadth. In addition there are smaller spindles and three-rayed forms, somewhat stringy in appearance and with fewer and simjjler protuberances. {/)) In the stalk there are spindles, clubs, irregular three- and four-rayetl forms, globular forms and irregular spindles. All are thickly covered by very rough or branched warts, and in addition on many spindles and other forms alike there are very long branched thorns. The spindles measure from 027 to 092 nun. in length and from 009 to 0'25 mm. in breadth. In addition there are a few spindles much smaller in size, with fewer and more s})ine-like [)ro- tuberances, and with a striated surface. Canal-wall spicules : ((/) In the stem there are small, flat, smooth spindle- to star-shaped forms and more irregular stars. (/>) In the stalk the spicules are slightly larger than in the stem, and are irregularly branched, flat and practically smooth forms, triangular foi-ms and irregular stars. They have an average length of 30 mm. and a breadth of 0-18 mm. Colour — The whole colony is dirty greyish-white. Locality : Persian Gulf. Dendronephthya dichotoma, Henderson. The colony is distinctly divaricate in type ; the shape is that of a bush, and the outline a regular oval, the long axis of the oval being at an angle to the main stem. It measures about 9 cm. in height and about 7 cm. in breadth. The short, stout stalk measures about one-half of the total length ; its upper part is concealed by reflexed flattened branches ; it is granular in appear- ance, gives off at its lower end a number of short, blunt stolons, and has an outer coating of large, rough spicules for a short distance up from its lower end. The polyparium is large and obliquely oval in shape, and is formed in the following manner : The main stem gives off flattened, leaf-like branches, con- tinues for a short distance entire, and then divides into two main portions one of which again divides into two main branches. From the surface of the main stem and branches smaller branches are given ofl' more or less at a right angle. 63 and these again divide in a roughly dichotomous manner into smaller branches or twigs which bear the polyps. The arrangement of the leaf-like branches is noteworthy— both are very large and form a collar almost surrounding the stem, leaving only two small spaces, at each of which a much smaller branch arises at a slightly lower level ; but these smaller branches, although ap- pearing leaf-like owing to their flat upper portion, have an almost cylindri- cal lower portion, in contrast to the two larger branches whose origin is almost as broad as the flattened portion and which may be called well-developed folds of the outer siuface. Smaller branches are given off from the upper surface of these, as from the stem and its main branches. From the ends and sides of the twigs and from the edges of the flattened branches the polyps arise in small bundles of three to eight indi- viduals and are placed on widely diverging stalks. The divaricate nature of the bundles tends to be masked by young polyps which arise at the base of a polyp-stalk or in the angle be- tween two stalks. A noteworthy feature is that there are apparently two kinds of polyps, (i) a larger with very well-developed Stutzbundel, and (ii) a smaller, with a weak Stutzbundel or with none. This apparent dimorphism is simply due to the juxtaposition of adult and young polyps. The polyps are small, measuring on an average 0'45 mm. long and 0'45 mm. broad, and are placed practically at a right angle on the stalk, which is slightly less than 1 mm. in length. The polyp-spicules are arranged in eight double rows in each of which there are five pairs of converging spicules, one or both of the uppermost pair being longer, and, especially in the lateral rows, projecting be- yond the polyp-head. The lower spicules are 030 mm. long, while one or both of the uppermost pair may reach a length of 1 mm. and project for a distance of 06 mm. All these have short, simple, regularly arranged thorns, which on the projecting tips show a tendency to upward direction. The Stutzbundel spicules are enormously developed and form a shield for the back of the polyp-stalk. They are usually four to five in number, one of which is generally especially long ; the longest may reach a length of 4 mm. and a breadth of 0"18 mm. and project for a distance of 1-2 mm., but the average Fig. 33. D. dichotoma. 64 length of the prominent spicule is about 3 mm. with a projection of <)) Those of the stalk are large spindles, either straight or curved, small clubs, three- and four-rayed forms and incipient four-rayed forms. Most of these are characterised by a thick coat of very rough warty protuberances, while a few are not so thickly covered and have simpler jjrotuberances. Colour — The stalk, stem and branches are white ; the polyps brick-red, although a tinge of yellow is visible in some parts of the smaller branches and in the polyp-stalks. Locality : Ganjam Coast, 15-25 fathoms. Dendronephthya ganjamensis, Henderson. The colony is bush-shaped and consists of a short stalk and two main branches. It measures 7 cm. in height and 6 cm. in maximum breadth. 65 The stalk 1ms hccn considerably