CORALLIFERI. 417 
After the Alcyonia are also placed the 
Sponeia, Lin.(1) 
Or Sponges; marine, fibrous hodies whose only sensible portion 
appears to be asort of tenuous gelatine which dries off, scarcely leav- 
ing a trace of it, and in which neither Polypi nor other moving parts 
have yet been discovered. Living Sponges are said to exhibit a sort 
of tremulousness or contraction when they are touched; it is also 
affirmed that the pores, with their superficies, are perforated, and 
present a sort of palpitation; the existence of these motions, how- 
ever, is doubted by M. Grant(2). 
Sponges assume innumerable shapes, each according to its spe- 
cies, and resemble shrubs, horns, vases, tubes, globes, fans, &c. 
Every one knows the 
S. officinalis, or common Sponge, which is found in large 
brown masses, formed of extremely fine, flexible, and elastic 
fibres, perforated with numerous pores and little irregular 
canals, all of which intercommunicate. 
(1) The genus of the Sponges is extremely rich in curious species, and would 
well repay its study. M. de Lamarck—An. sans Vert., U1, 345, et seq.—will prove 
an excellent guide. Seealso the important Memoir of M. Grant, Ann. des Sc, 
Nat., XI, pl. xvi. 
(2) M.; Audouin and M. Edwards, Ann. des Sc. Nat., XI, pl., xvi, have adopted 
this opinion of M. Grant. 
Vout. [LV.—3 C 
