8 Mr. H. J. Carter on three Pachytragous Sponges 



more or less areolar sarcode, which is in direct connexion 

 with the pores, and traversed by the brandies of the excretory 

 canal-system, which, uniting together, finally terminate in 

 their respective oscules ; charged more or less with the spi- 

 cules about to be described. Spicules of four kinds : — 1, the 

 largest (fig. 9), smooth, fusiform, acerate, slightly curved ; 2, 

 smooth, trifid (figs. 10 & 11), with shaft pointed at one end and 

 furnished with three arms at the other, spreading horizontally 

 in the opposite direction, slightly inclined forwards towards 

 the long axis of the shaft, vase-like, each terminated by bi- 

 furcatioai, which extends to a variable degree down the arm ; 



3, minute spinous spicule (fig.l2),sub-bistellate — that is, where 

 the spines are chiefly confined to the ends of the short shaft ; 



4, minute stellate spicule (fig. 13), a little larger than the latter, 

 with small body and long arms, wliich are incipiently spinous. 

 The large acerate spicules are very numerous and scattered 

 equally throughout the sponge ; the trifurcate spicules chiefly 

 confined to the surface, where, with the former, they lie almost 

 horizontally (fig. 8) ; the minute sub-bistellate spicules are chiefly 

 confined to the dermal layer, and the stellate spicules to the 

 body-substance of the sponge. 



Size variable ] largest specimens found about 4 inches in 

 diameter and about an inch thick. Cells variable, the largest 

 about 1-1 70th of an inch in diameter. Largest acerate spicule 

 about 1-lOth inch long; longest shaft of trifid spicule about 

 l-30th inch ; minute sul3-bistellate spicule about l-2000th inch 

 long, and stellate about 1-1 000th inch in diameter. 



Log. Budleigh-Salterton, south coast of Devon. Straight 

 Point. 



Hob. Same as the foregoing species, viz. Dercihis niger. 



Obs. This sponge possesses the spicule - character of 

 Schmidt's genus SteUetta^ and has hence been so named ; but 

 the celluliferous layer has not, I think, been yet noticed or de- 

 scribed, and hence it may be necessary hereafter to unite those 

 sponges which possess it into a separate group, if not one also 

 with a different appellation. 



It answers somewhat to the description of Ecionemia pon- 

 derosa, Bowerbank (Brit. Spong. vol. ii. p. 56) ; but there is 

 no " dark-pui-jDle " sarcode on the surface, nor is the surface 

 " smooth ;" nor are the furcated ends of the trifid spicule 

 reciirvedj as stated in the text and shown in the representation 

 of the type specimen (vol. i. pi. 28. fig. 355). Nor can it be his 

 " Tethya muricata^ MS. ;" for there are no " skeleton fasciculi," 

 the substance of the interior is all confused like that of Pachy- 

 mattsma, and the minute dermal spicule sub-bistellate, not 

 " elongo-attenuato-stellate," like that of Dr. Bowerbank's 



