S76 Dr. J. E. Gray on Hyalonema Scliultzei. 



If this theory is correct, it will add another synonym to 

 the genus Hyalonema j which already has many significations. 



1. Hyalonema^ Grray, Brandt, Bocage. The coil and polypes. 



The sponge, regarded as parasitic, named Garteria. 



2. Hyalonema^ Valenciennes, Milne-Edwards, Max Schultze, 



Wyville Thomson, Perceval Wright, Huxley. The 

 sponge and coil, the coil being regarded as a part of the 

 sponge {Garteria^ Gray). Polype regarded as a parasitic 

 species of Palythoa, 



3. Hyalonema^ Bowerbank, W. Carpenter. The sponge, coil, 



and bark. The bark or polypes regarded as a skin of 

 the coil and sponge, which they consider part of the same 

 organization. 



Excluded Species, 



4. Hyalonema^ sp. {horeale), Lov^n, Wyville Thomson. A 



sponge {Ficulina^ Gray) belonging to the family Hali- 

 chondriadse. 



5. Hyalonema^ sp. ihoreale)^ Bocage = a sponge {Loviniaj Bo- 



cage) belonging to the family Tethyadse. 



6. Hyalonema^ sp. [Scliultzei ^ SQiniper) == Semper elluy Gray* A 



sponge of the family Euplectelladse. 



No doubt great part of this confusion has originated in the 

 very strong predisposition of zoologists and physiologists to 

 believe that siliceous spicules can only be secreted by Proto- 

 zoa or sponges, and plants, as Diatoms, the grasses, Equi- 

 setum^ &c., though M. Haime says that he discovered siliceous 

 spicules in the bark of LeitopatheSj and Dr. Wyville Thomson 

 says that silica is present in the axis of Gorgonia^ and Dana 

 that it forms 23 per cent, of the chemical constituents of certain 

 Madrepores. 



Semperella may be thus defined : — 



A tubular vase-shaped sponge, with the tube closed with 

 a convex lid, and the wall of the tube formed of elongated, 

 slender, subcylindrical, thread-like, siliceous spicules, which 

 are kept in the vase-like form by the sarcode. The base con- 

 tracted, some of the thread-like spicules of the tube and 

 others being produced into a stem, which is sunk in the mud. 

 The radical filaments barbed near the end, and with a cup- 

 shaped anchor at the tip. 



Semperella Schultzei ^ Hyalonema Schultzei^ Semper. 



The difFerent^shape of the body of Euplectella aspergilluw 



