376 Dr. J. E. Gray on Hyalonema Schultze. 
If this theory is correct, it will add another synonym to 
the genus Hyalonema, which already has many significations. 
1. Hyalonema, Gray, Brandt, Bocage. The coil and polypes. 
The sponge, regarded as parasitic, named Carteria. 
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 (Carteria, 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. (boreale), Lovén, Wyville Thomson. <A 
sponge (Ficulina, Gray) belonging to the family Hali- 
chondriadee. 
5. Hyalonema, sp. (boreale), Bocage =a sponge (Lovénia, Bo- 
cage) belonging to the family Tethyade. 
6. Hyalonema, sp. (Schultze’, Semper) = Semperella, Gray. A 
sponge of the family Euplectelladee. 
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, Hgui- 
setum, &c., though M. Haime says that he discovered siliceous 
spicules in the bark of Letopathes, 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 Schultze’, Semper. 
The different shape of the body of Huplectella aspergillum 
