BRITISH SPONGIAD^. 155 



Section * * * Skeleton spicula, spinulate. 



Sub-section A, Skeleton spicula, smooth. 



29. Hymeniacidon suberca, Bowerbank. 



30. — carnosa, Bowerbank. 



31. — Jitais, Bowerbank. 



32. — sulphurea, Bowerbank. 



33. — sK^-c/fflUfl^fljBowerbank. 



34. — clavigera, Bowerbank. 



35. — celata, Bowerbank. 



36. — gelatinosa, Bowerbank, 



Sub-section B, Skeleton spicula, spinous. 



37. Hymeniacidon paupertas, Bowerbank. 



Section * * * * Skeleton spicula, cylindrical. 



38. Hymeniacidon Btyardinii, Bowerbank. 



Section ***** Skeleton spicula, angulated. 



39. Hymeniacidon Bucklandi, Bowerbank. 



1. Hymeniacidon Thomasii, Bowerbank. 



Sponge. Sessile massive, surface rugose. Oscula slightly 

 elevated, few, dispersed. Pores conspicuous, not very 

 abundant. Dermal membrane pellucid, thin, abun- 

 dantly spiculous, Spicula: of the skeleton, acerate, 

 stout, few ; of the interstitial membranes, acerate, slen- 

 der, abundant. 



Colour. — Dried, buff yellow. 



Habitat. — Black Rocks, Leith, Capt, F. W. L. Thomas, 

 R.N. 

 Examined. — In the dried state. 



