FRESHWATER AND LAND SHELLS. 13 



suites from Poland, Ohio, where they seem to be common. In the in- 

 terior it resembles U. pyramidatus (nobis). It is, however, easily dis- 

 tinguished by its being more compressed, less inflated on the umbones, 

 and in the beaks being less elevated. 



Unio solidus. Plate V. fig. 13. 



- Testa obliqua, injlataque ; valvuUs crassissimis ; natibus elevaiis retusisque ; epidermide 

 rufo-viridi; dentibus cardinalibus crassis ; lateralibiis obliquis, brevibusque ; margarita alba. 



Shell oblique, inflated; valves very thick; beaks elevated and letuse ; epidermis 

 rusty-green; cardinal teeth thick; lateral teeth oblique and short ; nacre white. 



Hab. Ohio River, at Cincinnati. T. G. Lea. 

 Mahoning River, Ohio. Dr Kirtland. 



My Cabinet. 

 Diam. 1-1, Length 1-7, Breadth 1-8 inches. 



Shell oblique, inflated, much enlarged at the umbones ; substance of 

 the shell very thick; beaks very much elevated, retuse, and possessed 

 of one or two undulations at the apex ; ligament rather short and thick ; 

 epidermis rusty-green, and sometimes obscurely rayed ; cardinal teeth 

 thick, crenate, and deeply cleft in the left, and emerging from a pit in the 

 right valve ; lateral teeth thick, slightly curved and nearly parallel with 

 the line of the cardinal teeth ; anterior cicatrices distinct, the great one 

 forming a deep pit ; posterior cicatrices distinct, the smaller one being 

 placed at the end of the lateral teeth ; dorsal cicatrices situated on the 

 interior of the plate between the cardinal and lateral teeth ; cavity of 

 the shell shallow ; cavity of the beaks rather deep and angular ; nacre 

 pearly white. 



Remarks. — This species has a strong resemblance to the U. undatus 

 (Barnes), and I have only now, after having had several specimens for 

 some years in my possession, satisfied myself, by examining complete 

 suites, of its being specifically different. It may be distinguished by 

 its being more rounded at the basal margin, by its more elevated beaks, 

 by its colour being more green, and, when the rays exist, in their be- 



VI. — D 



