COSCHYL] \—DITHTRA. 49. 



length, witli 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 distinc- 

 tion : 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 lesid trigond corned, costis IS confertis squamosis 

 Shell triangular horn-color, with 18 close-set scaly ribs. 



Tab. nost. 19, fig. 1. 

 Pinna pectinata. Linn. Syst. Xat. 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. Trans, viii. p. 113. 



Turton, British Fauna, p. 16o. 



Pennant, British Zool. p. 243. 



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



Dillvcyn, Descript. Catal. p. 32-5. 



Turton, Conch. Diet. p. 148. 

 Pinna muricata. Da Costa, p. 240, tab. 16, fig. 3. 



Donovan, British Shells, i. tab. 10. 

 Mus. nost. From the western coasts. 



peccmara. 

 3. 



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

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



