156 
CLASS III. — ORDER I. 
COAL, 
20. Spongia carbonaria . Unshapely, very stiff, 
and black ; texture fibrous, reticulated, and very po- 
rous. 
On the Millepora Alcicornis of the American 
seas. 
INCRUSTING. 
21. Spongia incrustans. Mass forming a thin, fi- 
brous, rose-coloured layer, on the surface of a fucus ; 
texture reticulated, fibrous, loose, and irregular, with 
rather large holes. 
Southern seas. 
AGARIC. 
22. Spongia agaricina. Compressed, lobed, ses- 
sile, reticulated, prickly, and osculated. 
Indian ocean, 
CRESTED. 
23. Spongia cristata. Even, upright, and soft ; 
pores projecting and regularly placed. 
Coasts of France and England. 
COTTAGE. 
24. Spongia domuncula. Convex; surface smooth, 
but covered with little papilla) ; very cellular within. 
Gulf of Genoa. 
GLOBULAR. 
25. Spongia globosa . Tough, and very cellul ar; 
surface covered with simple or branching protube- 
rances, elongated and rather stiff. 
Gulf of Genoa. 
