442 glauconomyidjE. 



Syn. Naranio, Gray. 



Ex. C. divaricatum, Chemnitz, pi. 110, fig. 2, 2, a. 



The shells of this genus have very much the external ap- 

 pearance and hinge of Coralliophaga, hut are easily known 

 hy the large sinus in the pallial line. They are generally 

 covered with a calcareous coating, which hides the rugosities 

 of the surface ; they live in stony corals. 



Species of Choristodon. 



divaricatum, Chem. radiatum, Gray. 



lapicidum, Chem. 



Fam. GLAUCONOMYIDjE. 



Lahial palps very large, hroadly falciform. Mantle- 

 margins plain, united, pedal opening anterior, rather large ; 

 siphons very long, compressed, united nearly to their ends, 

 orifices fringed; gills two on each side, long, rounded in 

 front, united behind, the outer pair shorter, and furnished 

 with a plaited, dorsal flap. Foot moderately large, thick, 

 compressed, linguiform, keeled. 



Shell oblong, thin, ventricose, closed, covered with a 

 green epidermis. Hinge narrow, with three teeth in each 

 valve, one of them bifid; ligament external, oblong, an- 

 terior. Muscular impressions oblong and marginal, the 

 hinder sub-quadrate ; pallial line with a deep, narrow, an- 

 gular sinus. 



Genus GLAUCONOMYA, Bronn. 



Shell oblong, covered with a hard, green epidermis ex- 

 tending beyond the edge of the valves. Hinge narrow, 



