UNITED STATES AND ARCTIC AMERICA. 197 



slightly compressed and corrugate; lateral teeth rather thick, corrugate, rather short 

 and nearly straight ; nacre white, rose color or salmon and very iridescent. 

 Proc. Acad. Nat, Sei., 1861, p. 392. 



Hob— Dallas, Texas, Prof. C. G. Forshey. 



My cabinet and cabinet of Prof. Forshey. 

 Diam. 1-1, Length 1-6, Breadth 2 inches. 



Shell smooth, triangular, inflated, slightly swollen at the beaks, obtusely angular 

 behind and rounded before, nearly equilateral ; substance of the shell rather thick, 

 thicker before ; beaks somewhat prominent, somewhat incurved, with a few rather 

 coarse undulations at the tips ; ligament rather long and dark brown ; epidermis 

 reddish brown, obscurely radiate, with somewhat distant, broad marks of growth ; 

 umbonial slope somewhat raised and obtusely angular ; posterior slope rather broad, 

 elongately cordate, with two somewhat rugose lines on each valve from the beaks to 

 margin ; cardinal teeth rather large, somewhat compressed and corrugate ; lateral 

 teeth rather thick, corrugate, rather short and nearly straight ; anterior cicatrices 

 large, distinct and well impressed ; posterior cicatrices rather large, distinct and 

 moderately well impressed ; dorsal cicatrices placed above the centre of the cavity of 

 the beaks ; cavity of the shell rather deep and rounded ; cavity of the beaks deep 

 and angular ; nacre white, salmon or rose color and very iridescent. 



Remarlcs. — Several specimens of different ages were received among the shells from 

 Prof. Forshey. The species is closely allied to trigonus, (nobis,) and is near to Rid- 

 ilellii, herein described. It may be distinguished from trigonus by its being more 

 lenticular in its form and not having so sharp an umbonial slope. From RiddellU it 

 may be distinguished by the want of the high beaks, the color of the epidermis and 

 the undulations of the beaks, which, in the above described species are few, as in 

 trigonus, and follow down the angle of the umbonial slope. On all the specimens 

 before me there are a few very indistinct rays over the disk. 



Unio Anthonyi. PI. 27, fig. 266. 



Testa lsevi, elliptica, inflata, ad latere planiuscula. postice obtuse biangulata, antice rotundata, insequi- 

 laterali; valvulis subtcnnibus, antice paulisper crassioribus ; natibus promiuulis; epidermide lutoo- 

 oliva, cradiata; dcntibus eardinalibus parvis, obliquis, subcompressis crenulatisque ; lateralibus 

 longis, laniellatis subcurvisque ; niargarita csruleo-alba et iridescente. 



Shell smooth, elliptical, inflated, slightly flattened at the sides, obtusely biangular 

 behind and rounded before, inequilateral ; valves rather thin, and slightly thicker 

 before ; beaks somewhat prominent ; epidermis yellowish olive, without rays ; cardi- 

 nal teeth small, oblique, somewhat compressed and crenulate; lateral teeth long, 

 lamellar and somewhat curved ; nacre bluish white and iridescent. 

 Proc Acad. Nat, Sei., 1861, p. 41, 



Hah. — Florida, J. G, Anthony, 



