G. ALCYONIUM. 251 



In the running and still waters in the environs of 

 Paris, particularly at the fountain of Bagnolet. 



COMPACT. 



41. Alcyonium compactum. A globulous and ra- 

 ther irregular mass, perhaps detached ; surface sleek ; 

 flesh firm and corky in a dry state. 



Var. B. Lower part almost pointed. 



Atlantic Ocean. 



Nota. This last species commences the second 

 section of M. Lamarck's Alcyonias, which are distin- 

 guished from the first by the non-apparent oscules of 

 the cells on the dry Polypidom ; it includes the Alcyo- 

 nium compactumy medullar e^ pcoiiceum, testudinariu??i, 

 orhiculatum, radiatumj cuspidiferum, grarmlosum, putri- 

 dosum, purpureitm, boletus, boletiforme, gelatinosum, and 

 bursa. The last of these I have placed among the Tha- 

 lassiophytes, under the name of Spongodium bursa ; 

 the Alcyonium gelatinosum evidently belongs to the 

 genus ; all the others are doubtful, and perhaps form 

 an intermediate group between the Alcyonias and 

 the Spongias. 



MARROW OF THE SEA. 



42. Alcyonium medullare. 



43. Alcyonium paniceum. See the description of 

 Spongia panicea, (p. 157). 



TORTOISE. 



44. Alcyonium testudinarium. Elliptical patches, 

 a little convex above, and concave below, friable, and 

 reticulated ; the upper surface garnished with a coat- 



