XIV. 



CONCHYLIA— D/TjErFi2^. 



a. Petricola. — l^esta suhhians, dentihus duobus inter ties 

 penetrantibus. 

 Shell somewhat open, with two teeth in one 

 valve closing between three in the other. 



'JO. Venus. — Testa clausa, dentibus tribiis infernh approximatis 

 supernh divergent thus. 

 ■ Shell closed, with three teeth which are close toge- 

 ther at their base and divergent at their tips. 



7. Venerupis. — Testa antich Mans, dentibus tribus approxi- 

 matis parallelis. 

 Shell open at the anterior end, with three teeth 

 all close together and parallel. 



37. CvTHEREA. — Dentes quatuor in valvd altera, ujiico remo- 

 tiusculo. 

 In one valve four teeth, one of them rather remote. 



14. Anatina. — Dentes cochlearifonnes, mutici. 



Teeth spoon-shaped without additional denticle. 



15. LiSTERA. — Dentes cochleariformes, cum denticidis adjectis. 



Teeth spoon-shaped with additional denticles. 



54. Unio. — Dentes subconici, striato-tnberculati. 



Teeth somewhat conic, striate or tubercled. 



13. PanoPjEA. — Dentes conici, et hinc callum breve. 



Teeth conic, and a callosity on one side. 



38. Arca. — Cardo rectilinearis, dentibus numerosis. 



Hinge in a straight line, with numerous teeth. 



