12 NEW UNIONID^ OF THE 



Unio Baldwinensis. pi. 51, fig. 155. 



Testa la vi, oblonga, cotnpressa, ad latere planulata, in£equilaterali, postice biangulata ; val vulis subcrassis, antice 

 paulisper crassioribus ; natibus prominulis; epidermide vel luteola vel fusca, eradiata; dentibus 

 cardinalibus parviusculis, subcompressis, subelevatis, crenulatis, in utroque valvule subduplicibus ; 

 •lateralibus praelongis, lamellatis subrectisque ; margarita vel alba vel salmonis colore tincta et vald6 



Shell oblong, compressed, flattened at the sides, inequilateral, biangular behind ; • 

 valves rather thick, a little thicker before; beaks a little prominent; epidermis 

 yellowish or brown, without rays; cardinal teeth rather small, rather compressed, 

 somewhat raised, crenulate, somewhat double in both valves ; lateral teeth very long, 

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

 Proc. Acad. Nat. Sei., 1859, p. 170. 



Hah. — Carter's Creek, Baldwin County, Georgia. J. Postell. 



My cabinet and cabinet of Mr. Postell. 

 Diam. -7, Length 1-4, Breadth 2-6 inches. 



Shell oblong, compressed, flattened at the sides, tnequilateral, biangular behind and 

 round before ; substance of the shell rather thick, slightly thicker before ; beaks a 

 little prominent ; ligament rather long and thick ; epidermis yellowish or brown, 

 without rays, with distant lines of growth; umbonial slope slightly raised and 

 obtusely angular ; posterior slope raised into a carina, with two slightly raised lines 

 passing, in each valve, from the beaks to the posterior margin ; cardinal teeth rather 

 small, rather compressed, somewhat raised, crenulate, double in the left and slightly 

 double in the right valve; lateral teeth very long, lamellar, nearly straight and 

 terminated at the posterior end by a slight enlargement; anterior cicatrices distinct, 

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

 slightly impressed ; dorsal cicatrices placed above the centre of the cavity of the 

 beaks ; cavity of the shell shallow and wide ; cavity of the beaks very shallow and 

 rounded ; nacre white or salmon color and very iridescent. 



Eemarks. — I have three specimens before me, neither of them very perfect. The 

 one figured is moderately well preserved^ but still the beaks are eroded so that the 

 character of the undulations cannot be given. None were received in alcohol, thus 

 the character of the soft parts are not known. This species belongs to the great 

 complanatus group, and is nearly allied to the Savannahensis (nobis). It is more 

 oblong, more compressed and not so high on the umbonial slope. It also reminds one 

 oisiKidiceus (nobis). Two of the specimens have a fine salmon colored nacre, the 

 other is white, with a slight tint of salmon. The largest specimen, three and a 

 quarter inches wide, has a well defined ventral cicatrix in each valve. 



