Report on the zoological collections made in the Indo-Pacific Ocean ...

590 COILECTIOKS FROM THE "WESTERN INDIAN OCEAN.CERATOSA.This Order is well represented, viz. by 17 species (or 31 per cent.),as the tropical position of the localities would load one to expect.Carterisjjongia is the dominant type, and probably more abundanthere in species, and not less so in individuals, than in any other partof the world ; the two aberrant Hippospongice described are alsowonderfully abundant. A Mediterranean type, Oligoceras, is forthe first time recorded from the Indo-Pacific area.SPONGIIDJE.1. Cacospongia cavernosa.Schmidt, Sjiong. Adr. Meer. p. 28 ; F. E. Schulze, Zeitsch. wiss. Zool.xxxii. p. 653, pis. xxxiv. fig. 11, pi. xxxv. fig. 17, pi. xxxvii. figs. 7, 13.In spite of the remarkable geographical distribution which isinvolved by identifying the present specimens with a Mediterraneanspecies, the identity seems to me fairly certain. The charactersagree well with those given by Schmidt and with Schulze'sfigures. The conuli are 2-4 millim. high and about 5 millim.apart, in spirit ; the colour in spirit is dark grey ;the primaryfibres measure •18-*24 millim. in diameter. Vents numerous, 2-3millim. in diameter, grouped at summits of the lobes formed by thesponge. Eepresented here by semi-repent masses growing betweenand over stones or rocks, and sending up cylindrical lobes 18-25millim. in diameter, which tend to divide above and to attach foreignbodies to themselves. The skeleton shows an irregularly rectangulararrangement of the fibres similar to that figured by Schulze.Hab. Seychelles Islands, 4-12 fms.Distribution. Adriatic (Schmidt and Schulze) ;Algiers {Schmidt).2. Hippospongia intestinalis, var. (Plate LIII. fig. D.)Spongia intestiiiafis, Lnmarclc, Ann. Mus. Hist. Nat. xx. p. 434.Spongelia velata, Hyatt, Mem. Bost. Soc. ii. p. 634, pi. xvii. fig. 8.The tortuous perforated tubes are sometimes single, but sometimesform confused reticulate masses (see fig. D, Plate LIII.), which, whenthe soft tissues are dried on them, have a very different appearance,and as such have been described under the above separate name byHyatt, whose figure well represents this state ; their diameter variesfrom about 5 to 20 millim. The surface is covered in fresh specimensby a delicate diteliform network, as stated by Hyatt, and as foundin our specimens ; the sarcodo in spirit is opaque pale brownishyellow. The species must be nearly related to Hircinia clathrata.Carter ; but that species would seem to assume a decidedly verticalgrowth, whereas this has the appearance of being subrepent.Mr. Carter's description of that form speaks of sand-cored fibre asonly occurring here and there, esjiecially near the surface, whereasin H. intestinalis long straight primary fibres cored with foreign