38 DESCRIPTION OF FIFTY-TWO SPECIES OF UNIONID^. 



impressed; dorsal cicatrices placed nearly in the centre of the cavity of the beaks; 

 cavity of the shell rather deep and wide; cavity of the beaks shallow and obtusely 

 angular; nacre whitish, rich and very iridescent. 



Remarks. — Many years since I received from the late Dr, Budd of New York 

 two opposing not well matched valves of this Unio. Both valves evidently belonged 

 to females and both were much eroded. Not being entirely satisfied from imperfect 

 odd valves that they belonged to an undescribed species, I placed them aside in 

 the hope of getting others from Florida like them. The provided name vesicularis 

 was placed on the label. Now after about twenty years my friend C. M. Wheatley, 

 of Phoenixville, sends me a single smaller specimen from Lake Ocheechobee, 

 which is evidently a male. The description and figure are made from this more 

 perfect specimen. In outline it is very much the same with parvus Bar., but it is 

 not so thick a species and the epidermis is lighter colored and is rayed. Neither 

 of the specimens is perfect enough to exhibit the undulations of the beaks, which 

 is much to be regretted, as this character might give us with certainty the key to 

 the group in which it belongs. 



Unio curvatus. PI. 13, fig. 35. 



Testa Isevi, late oblonga, subinflata, ad latere planulata, valde insequilaterali, postice angulata, antice 

 rotundata; valvulis parum crassis, antice crassioribus; natibus prominulis; epidermide tenebroso- 

 fusca, aliquanto polita, eradiata; dentibus cardinalibus parvis, sulcatis, compressis, in utroque 

 valvulo duplicibus ; lateralibus longis, lamellatis subrectisque ; margarita pallido salmonia vel 

 purpurascente et valde iridescente. 



Shell smooth, widely oblong, somewhat inflated, flattened at the sides, very ine- 

 quilateral, angular behind, rounded before; valves somewhat thick, thicker before; 

 beaks a little prominent; epidermis dark brown, somewhat polished, without rays; 

 cardinal teeth small, sulcate, compressed, double in both valves ; lateral teeth long, 

 lamellar and nearly straight; nacre pale salmon color or purple and very iridescent. 

 Proc. Acad. Nat. Sci., 1812, p. 159. 



Hab.—Fi'ei&r's Pond, Mecklenberg Co., North Carolina, C. M. Wheatley. 



My cabinet, and cabinet of C. M. Wheatley. 

 Diam. -7, Length I'l, - Breadth 2-4 inches. 



Shell smooth, widely oblong, somewhat inflated, flattened on the sides, very ine- 

 quilateral, angular behind, rounded before; substance of the shell somewhat thick, 

 thicker before ; beaks a little prominent, placed towards the anterior end ; ligament 

 long, thin and brown; epidermis dark brown, somewhat polished, without rays, 

 with two or three distant marks of growth well developed; umbonial slope obtusely 

 angular; posterior slope subcarinate, narrow elliptical ; cardinal teeth small, sul- 



