HYMENIACIDON. 79 



16. HYMENIACIDON PERL^VIS (Montagu), n, 179; in, 

 PI. XXXIV, figs. 1, 2. 



1867 Reniera perlcevis, Gray. Proc. Zool. Soc., p. 518. 



Habitat. Bantry Bay (N.). 



17. HYMENIACIDON PACHYDERMA, Bow., n, 184; in, 

 PI. XXXIV, figs. 10, 11. 



1867 Reniera pachyderma, Gray. Proc. Zool. Soc., p. 518. 



18. HYMENIACIDON CRUSTULA, Bow., u, 185; in, PI. 

 XXXIV, figs. 36. 



1867 Reniera crustula, Gray. Proc. Zool. Soc., p. 518. 



19. HYMENIACIDON HILLIERI, Bow. 9 TL. sp.,iv, PI. Ill, figs. 

 13. 



' ' Sponge massive, sessile. Surface smooth and even. 

 Oscula simple, dispersed. Pores inconspicuous. Der- 

 mal membrane aspiculous. Skeleton dense, abun- 

 dantly spiculous. Spicula -acuate, rarely subspinulate ; 

 closely felted together in all parts of the sponge. 

 Sarcode at the surface nearly black, opaque; inter- 

 nally light coloured and semi-transparent. 



ct Colour. In the living state, dark brown, nearly 

 black. In the dried state, dark nut brown. 



" Habitat. On oyster shells from the Ridge off 

 Dover ; James F. Hillier, Esq., of Kamsgate. 



