78 CONCHYLIA— D/THYEJ. 25. 



In size and form it exactly resembles the Goodallia triangularis, 

 among which it has doubtless been overlooked, but presents the same 

 differences as are observed between the Crassina sulcata and Crassi- 

 na Scotica, the margin being thinner and without the least appear- 

 ance of crenulations. 



25. SOLEN— L/A^iVK 



Testa transversim lineari-producta, wquivalvis, inwquilateralis, lateri- 

 bus hiantibus. Cardo subterminalis, umbonibus obsoletis, dentibus 

 numero et forma varus : lateralibus nullis. Ligamentum externum. 



Shell transversely produced and linear, equivalve, inequilateral, open 

 at the sides, Hinge near one end, with the beaks obscure, and 

 the teeth varying in number and shape : lateral teeth none. Lig- 

 ament external. 



We have confined this genus to those of the Linnean family of 

 the Solen which have a linear and elongated form, as affording a 

 more simple and definite discrimination. 



The processes which extend along the cartilage edge of most of 

 them, can hardly be considered as lateral teeth, being attached in a 

 rib-like manner to the valves. 



