12 DESCRIPTION OF NEW 



Unto coccineus. Plate V. fig. 12. 



Testa subtriangulari, obliqua et subcompressd, ; valvulis antice crassioribus ; natibus sub- 

 elevatis retusisque ; dentibus cardinalibus crassis ; lateralibus crassis et subcurvis ; margarita 

 coccinea. 



Shell subtriangular, oblique and somewhat compressed ; valves thicker anteriorly ; 

 beaks rather elevated and retuse ; cardinal teeth thick ; lateral teeth thick and some- 

 what curved; nacre bright red. 



Hab. Ohio Eiver, near Marietta. Dr Hildreth. 

 Mahoning river, Ohio. Dr Kirtland. 

 Near Columbus, Ohio. MrLapham. 



My Cabinet. 

 Cabinet of P. H. Nicklin. 

 Cabinet of W. Hyde. 

 Cabinet of Professor Vanuxem. 

 Unio coccineus. Dr Hildreth's letter. 

 Diam. 1-7, Lengths, Breadth 2-2 inches. 



Shell subtriangular, oblique, somewhat compressed ; substance of the 

 shell thick anteriorly and thinner posteriorly; beaks rather elevated, 

 retuse, and possessed of one or two undulations at the apex ; ligament 

 rather long and curved; epidermis dark reddish brown, with regular 

 distinct marks of growth ; cardinal teeth large, crenate, and deeply 

 cleft in the left valve, and emerging from a pit in the right ; lateral 

 teeth rather long, thick, and somewhat curved ; anterior cicatrices dis- 

 tinct, the great one forming a deep pit ; posterior cicatrices distinct, 

 the smaller one being placed at the end of the lateral tooth ; dorsal 

 cicatrices situated on the inferior part of the cardinal tooth ; cavity of 

 the shell sha'low; cavity of the beaks rather deep and angular; nacre 

 bright red, sometimes salmon, rarely white. 



Remarks. — About eighteen months since, Dr Hildreth sent me a 

 single specimen of this species, which he communicated under the 

 name of coccineus. I have since received from Dr Kirtland some fine 



