GENERA OF CLASS III. 145 



branches ; covered with a thick cylindrical rind, irre- 

 gularly set with polypean projections. 



Primnoa. Tree-formed and dichotomous, with long 

 and conical projections, internally as well as exter- 

 nally formed like bags or purses, which are pendent, 

 imbricated, and covered with scales that are also im- 

 bricated. 



Corallium. Polypidom tree-formed and iuarticu- 

 lated; axe stony, stiff, and susceptible of a high 

 polish ; rind fleshy, becoming cretaceous and very 

 friable by desiccation, and adhering to the axe. 



GENERA 



BELONGING TO THE THIRD ORDER OF THE THIRD CLASS. 



Tree-formed Polypidoms ; composed of a rind, 

 similar to that of the last order, but with an articu- 

 lated axe; the articulations alternately horny or 

 corky, and calcareously stony. 



Melitea. Polypidom tree-formed and knotty ; with 

 branches generally anastomosised ; stony articulations, 

 substriated ; the intermediates spongy and swelled ; 

 rind cretaceous, very thin, and friable in a state of 

 desiccation ; polypi on the surface, or tubercular. 



Cor. T 



