CO'iiiCEYLIA—DITHYRA. 49. 22:5 



length, with the upper part rounded and produced, giving it a more 

 ham-like appearance ; the smaller end also runs in a more straight 

 direction. 



The different outlines of these two species are constant, and, as 

 we are inclined to think, sufficiently point out specific distinction : 

 both of them, when young, have a few spines on the ribs, which 

 ribs however are indistinct, and fewer in number than those of the 

 next species. 



Pinna testa trigond corned, costis 18 confertis squamosis. pectinata. 



Shell triangular horn-color, with IS close-set scaly ribs. 



Tab. nost. 19, fig. I. 

 Pinna pectinata. Linn. Syst. Nat. p. 1160. 



Gmelin, Syst. p. 3363. 



Turton, Linn Syst. iv. p. 301. 



Chemnitz, viii. p. 213, tab. 87, fig. 770. 



Montagu, Test. Brit. p. 178. 



Linn. Tram. viii. p. 113 



Turton, British Fauna, p. 165. 



Pennant, British Zool. p. 243. 



Dorset Catal, p. 41, tab. 3, %.3. 



Dillwyn, Descript. Catal. p. 325. 



Turton, Conch. Diet. p. 148. 

 Pinna muricata. Da Costa, p. 240, tab. 16, fio-. 3. 



Donovan, British Shells, i. tab. 10. 

 Mus. nost. From the western coasts. 



Shell three or four inches long, and two inches wide, pale 

 horn-color, thin and brittle, with about 18 crowded ribs, which 



