416 



VENERIDvE. 



compressed, serves to distinguish it from Anapa, where the 

 shell is trigonal and ventricose. D. plana is from the 

 Philippines. 



Species of Davila. 



crassula, Desk. retusa, Desk. 



plana, Hartley. 



Genus ERVILIA, Turton. 



Shell equivalve, inequilateral, oblong, closed: surface 

 nearly smooth, or transversely striated. Hinge with two 

 diverging teeth in each valve, one of them, in the right 

 valve, elevated and conspicuous ; cartilage internal, in a car- 

 tilage-pit in each valve ; lateral teeth none. Muscular im- 

 pressions strong; pallial sinus large and broad. 



Ex. E. castanea, Montagu, pi. IOC, fig, 7, 7, a. 



The species of Ervilia known are from deep water, and 

 inhabit the West Indies, Britain, the Canaries, and the 

 Mediterranean and Red Seas. 



Species of Ervilia. 

 castanea, Mont. nitens, Mont. 



Fam. VENERIDiE. 



Labial palps small, triangular, acute. Mantle with a 

 somewhat large pedal opening ; siphons short, unequal, 

 united for the greater part of their length ; gills large, sub- 

 quadrangular, united behind. Foot large, compressed, 

 linguiform, sometimes furnished with a byssal groove. 



Shell regular, free or perforating, closed or somewhat 



