122 Mr, H. J. Carter on 



Obs. There are four specimens of this sponge, all more or 

 less alike, but one is double-headed. At first thej look so 

 much like specimens of Donatia that one is inclined to place 

 them in the same group ; however, the stipitate form (there 

 is no stem in Donatio) and the spiculation soon dispels this 

 delusion. 



Group 15. Do NAT IN A. 



26. Tethea Cliftoni, Bk. 



Tethea Cliftoni, Bk., Proc. Zool. Soc. 1873, p. 16, pi. iii. figs. 14 &c. 

 Donatia, Gray, ib. 1867, p. 541. 



This seems to me to be onlj an enlarged form of our 

 Donatia Jyncurium^ and therefore ought to be considered a 

 variety rather than a distinct species. The surface is more 

 prominently tuberculated and the root-like appendages larger 

 and more prolonged than in the British species ; but the 

 colour is pink or orange when fresh and the spiculation and 

 internal structure are nearly the same. There are several 

 specimens in Mr. Wilson's collections averaging 2 inches in 

 diameter, which is twice the size of the British species (see my 

 illustrated description of the latter, * Annals,' 1869, vol. iv. 

 p. 7, pi. ii. figs. 1-8). In distribution it seems to be " world- 

 wide." 



Group 19. C II N D R P S I N A (new group, provisional). 

 27. Chondropsis arenifera. 



More or less globular, sessile. Consistence firm, almost 

 unyielding. Colour when fresh '' buff or reddish grey," 

 now whitish grey externally. Surface irregular, but smooth. 

 Vents numerous, irregular in size, large, scattered over the 

 surface, especially round the summit. Spicules of two forms, 

 accompanied by a great quantity of sand : — 1, Skeletal, cylin- 

 drical, with obtuse ends, 70 by f-6l)00th in, ; 2, acuate, much 

 smaller, viz. 50 by |-6()00th in. Sand diffused, not circum- 

 scribed, that is not in the form of fibre. Structure from without 

 inwards consisting of a thin reticulate dermis whose fibre is 

 charged with minute acuates mixed with grains of sand, pass- 

 ing into a cartilaginous fibreless tissue partly charged with 

 the spicules above mentioned in yellow sarcode, and partly 

 with grains of sand throughout^ that is presenting no nuclear 

 condensation. When dry the sand appears in aggregations 

 distinct from the yellow sarcode, then of a brown colour like 

 glue, in which the spicules are chiefly imbedded. Size of 



