144 GENERA OF CLASS III. 



whitish, soft, and corky ; this axe is enveloped either 

 in a gelatinous and fugitive exterior, or a fleshy rind of 

 greater consistency, which is animated and frequently 

 irritable, becoming more or less cretaceous by desic- 

 cation, and enclosing the Polypi, as well as their cells, 

 when there are any. 



Anadyomena. Fan-shaped, furrowed with articu- 

 lated and symmetrical nerves ; almost transparent, 

 and enveloped with a gelatinous substance. 



Antipathes. Tree-formed, simple or branched ; 

 axe horny, usually hairy or stuck with small spines, 

 rarely smooth ; rind polypiferous, gelatinous and slip- 

 pery, almost wholly disappearing by desiccation. 



Gorgonia. Polypidom tree-formed, simple or 

 branched ; branches dispersed or coming from the 

 sides ; free or anastomosed ; axe longitudinally stri- 

 ated, hard, horny, and elastic, or pithy and brittle ; 

 rind fleshy and animated, becoming cretaceous by 

 desiccation ; polypi either not projecting beyond the 

 rind, or when dead forming small tubercles on its 

 surface. 



Plexaura. Tree-formed, branching, and frequently 

 dichotomous ; branches cylindrical and stiff; axe 

 slightly compressed ; rind, in a state of desiccation, 

 corky or earthy, very thick, and eff'ervescing in acids ; 

 covered with large and numerous dispersed cells, 

 frequently of unequal sizes, and never projecting. 



Eunicea. Tree-formed and branching ; generally 

 compressed, and mostly so at the junction of the 



