590 COLLECTIONS FROM THE AVESTERN INDIAN OCEAN. 



CERATOSA. 



This Order is well represented, viz. by 17 species (or 31 per cent.), 

 as the tropical position of the localities would lead one to expect. 

 Oarterispongia is the dominant type, and probably more abundant 

 here in species, and not less so in individuals, than in any other part 

 of the world ; the two aberrant Hippospongioe described are also 

 wonderfully abundant. A Mediterranean type, Olujoceras, is for 

 the first time recorded from the Indo- Pacific area. 



SPONGIID^E. 

 1. Cacospongia cavernosa. 



Schmidt, Spnng. Adr. Meer. p. 28 ; F. E. Schulze, Zeitsch. wiss. Zool. 

 xxxii. p. (353, pis. xxxiv. fig. 11, pi. xxxv. fig - . 17, pi. xxxvii. figs. 7, 13. 



In spite of the remarkable geographical distribution which is 

 involved by identifying the present specimens with a Mediter- 

 ranean species, the identity seems to me fairly certain. The cha- 

 racters agree well with those given by Schmidt and with Schulze's 

 figures. The conuli are 2-4 millim. high and about 5 millim. 

 apart, in spirit ; the colour in spirit is dark grey ; the primary 

 fibres measure '18-*24 millim. in diameter. Yents numerous, 2-3 

 millim. in diameter, grouped at summits of the lobes formed by the 

 sponge. Represented here by semi-repent masses growing between 

 and over stones or rocks, and sending up cylindrical lobes 18-25 

 millim. in diameter, which tend to divide above and to attach foreign 

 bodies to themselves. The skeleton shows an irregularly rectangular 

 arrangement 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 intestinalis, Lamarck, Ann. Mns. Hist. Nat. xx. p. 434. 

 Spongelia velata, Hyatt, Mem. Bost. Soc. ii. p. 534, pi. xvii. fig. 8. 



The tortuous perforated tubes are sometimes single, but sometimes 

 form confused reticulate masses (see fig. D, Plate LIII.), which, when 

 the soft tissues are dried on them, have a very different appearance, 

 and as such have been described under the above separate name by 

 Hyatt, whose figure well represents this state ; their diameter varies 

 from about 5 to 20 millim. The surface is covered in fresh specimens 

 by a delicate diteliform network, as stated by Hyatt, and as found 

 in our specimens ; the sarcode in spirit is opaque pale brownish 

 yellow. The species must be nearly related to Hircinia clathrata, 

 Carter ; but that species would seem to assume a decidedly vertical 

 growth, whereas this has the appearance of being subrepent. 

 Mr. Carter's description of that form speaks of sand-cored fibre as 

 only occurring here and there, especially near the surface, whereas 

 in //. intestinalis long straight primary fibres cored with foreign 



