4 CONCHYLIA— D/T/fFE^. 1. 



soft calcareous sandstone and submarine peat in Torbay, whence we 

 have taken it alive at the lowest equinoctial tides. 



lamellata. Pholas testd latere antico hiantissimo, postico rotundato subclauso, 

 margins supra denies lamella erectd, accessoriis nullis. 



Shell very open at the anterior end, rounded and nearly closed at 

 the other, with an erect laminar process on the margin above the 

 teeth, and without accessorial valves. 



Tab. nost. 1. fig. 5 and 6. 



Mus. nost. Found with the last. 



Shell more than half an inch long, and an inch broad, oval, white, 

 without accessorial valves, with a very large oval opening on the 

 anterior side, where the margins of the valves are flattened and a 

 little reflected, and produced into a short beak, covered entirely with 

 close-set rather oblique transverse crenate ribs, which beyond the 

 longitudinal groove are coarser and straighter ,• the smaller end 

 rounded and nearly closed : inside with a longitudinal rib in the 

 middle; the teeth long, slender, and flat, and on the margin above 

 them is a triangular process, as in the last. 



It has been suggested to us, that a belief is entertained of this 

 shell being the young of Pholas papyracea. But as we have oppor- 

 tunities of examining each of them in every stage of their growth, 

 both perfect and with the valves separated, we can with confidence 

 assert, that no two species of the same genus are more dissimilar, 

 and distinct in their essential characters. 



Independently of the total want of the ring, and the large 



