BAPHIA. 499 



Genus BAPHIA, Meuschen. 



Gills generally free from the abdominal sac, and their 

 posterior extremity not united to the mantle; anal opening 

 not fringed, branchial mostly fringed. 



Shell transverse, oblong, equivalve, covered with an 

 olivaceous epidermis. Hinge with a single cardinal tooth 

 in the right valve, broad, erect, and grooved at its apex ; 

 twin teeth of left valve strong, the hinder denticulated, 

 the front narrower, entire, pointed; lateral teeth not de- 

 veloped. 



Syn. Margaritana, Schum. Unio, Oken, not Retz. 

 Damalis, Leach, Hemilastena, Rqfin. 



Ex. B. margaritifera, Linnmus, pi. 117, fig. 2, 2, a. 



Of Baphia there are two undoubted species in the fresh- 

 waters of Europe, besides numerous reputed species ; all 

 the others are from the rivers and lakes of North America. 



Species of Baphia. 



Bonellii, Ferus. Hildrethiana, Lea. 



dehiscens, Lea. Holstonia, Lea. 



fabula, Lea. margaritifera, Linn. 



Sub-gen. alasmodonta, Say. 



Shell trigonal, nearly equilateral ; surface of valves smooth ; 

 beaks large, prominent. Hinge with two cardinal teeth. 



Curreyana, Lea. minor, Lea. 



deltoidea, Lea. undulata, Lea. 



