BRITISH SPONGIADiE. 155 



Section * * * Skeleton spicula, spiimlate. 



Sub-section A, Skeleton spicula, smooth. 



29. Hymeniacidon suberca, Bowerbank. 



30. carnosa, Bowerbank. 



31. jicus, Bowerbank. 



32. sulphurea, Bowerbank. 



33. sub-clavata, Bowerbank. 



34. clavigera, Bowerbank. 



35. celata, Bowerbank. 



36. gelatinosa, Bowerbank. 



Sub-section B, Skeleton spicula, spinous. 



37. Hymeniacidon pauper tas, Bowerbank, 



Section * * * * Skeleton spicula, cylindrical. 



38. Hymeniacidon Dujardinii, Bowerbank. 



Section ***** Skeleton spicula, angulated. 



39. Hymeniacidon Bucklandi, Bowerbank. 



* 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. 



