REPOET ON THE KERATOSA. 29 



Phyllospongia, Cartenospongia. 



The first of these genera was created by Ehlers/ the second by Hyatt ; ^ both have 

 been united by the last-named naturalist into a special family Phyllospongiadse, char- 

 acterised by the leaf-like shape of its representatives, those of the genus Phyllospongia 

 being lamelliform and with the external surface quite smooth, those of the genus 

 Carteriospongia, though still lamelliform, very often indeed provided with numerous 

 lateral outgrowths, but far thicker, and probably in physiological hannony with this 

 latter peculiarity, with the outer surface presenting on its whole extension an alternation 

 of more or less deep elongated hollows, and more or less high, also elongated, tubercles. 

 I also think that both these genera are closely allied to one another, but this is only 

 my individual opinion, for while the skeletal fibres of Phyllospongm, thin and elastic as 

 they are, recall those of Euspongia, the skeletal fibres of Carteriospongia, far thicker than 

 the preceding and overcharged with foreign enclosures, resemble those of Cacospongia, the 

 possibility is not excluded that the PhyllospongicB are modified Euspongice, the Carterio- 

 spongice, on the contrary, modified Cacospongia. It may be further stated tliat the natural 

 systematic place of Carteriospongia is among the Spongelidse (comp. p. 17), while Phyllo- 

 spongia as regards its internal organisation belongs to the Spongidae. On the other hand, 

 the chief point concerning their external shape seems to be also of a rather ambiguous 

 nature, owing to the great variability of the form of the body in the group Keratosa, and 

 particularly of the true Spongidse. And it is very possible that though 0. Schmidt^ united 

 SpongioneUa, Bowerbank, with his Cacospongia, the species Spongionella pidchella, 

 Bowerbank, instead of being a British variety of Cacospongia scalaris as Schmidt sup- 

 poses, is merely a link connecting the true Spongidae with Phyllospongia. At least the 

 figure of Spongionella pidchella given by Bowerbank in his Monograph* recalls very much 

 that of Spongia [Phyllospongia) papyracea in Esper's Pflanzenthiere, the only distinction 

 consistino- in the comparative thickness of specimens which are leaf-like in both cases ; 

 and, on the other hand, it must be noticed that as to the second species of Spongionella 

 described by Bowerbank [Spongionella holdsworthii) , Carter^ identifies it directly with. 

 Spongia papyracea, Esper. To sum up, — the afiinities of both the genera I am speaking 

 of are surrounded by no less uncertainty than those of the genera Euspongia, Cacospongia, 

 &c., the generic distinctions being of the same conditional character. 



Oligoceras, Hircinia, Ceratella. 



The genus Oligoceras, established by F. E. Schulze " for some specimens from Lesina, 

 is indeed one of the worst genera. Marshall ^ classes it under his Dysideidse, and this 



1 Die Esper'schen Spongien, p. 23. ^ Revision, &c., vol. ii. p. 540. 



3 Spong. d. adriat. Meer., Bd. ii., Suppl., p. 9. * Vol. iii., pi. Ixv. fig. 5. 



5 Ann. and Mag. Nat. Hist., ser 4, vol. xvi. p. 193. " Zeitschr.f. iciss. ZooL, Bd. sxxiii. p. 34. '' Ibid., Ed. x.xxv. p. 92 



