DESCRIPTION OF FIFTY-TWO SPECIES OF UNIONID^. 37 



and deeply impressed; posterior cicatrices very distinct and deeply impressed; 

 dorsal cicatrices placed on the upper side of the cavity of the beaks ; cavity of the 

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

 nacre silver-M^hite and iridescent. 



Eemarks.— Among the specimens sent last season by Miss Law to Dr. Lewis 

 was a single specimen, large for the species and well developed, but with beaks 

 much eroded. During the present year (1871) Miss Law sent from Clinch River 

 four other specimens, smaller but in better condirion. The youngest is not quite 

 one-third grown and has a bright polished, yellow epidermis neariy covered with 

 delicate green rays; in this respect resembling Edgarianus (nobis). The three 

 specimens of intermediate age are nearly of one size, have dark epidermis with a 

 few very obscure rays on the umbones. The sides of the valves are so impressed 

 as neariy to make a wide furrow, and this indenture causes the emargination of the 

 basal margin. This species emphatically belongs to the Edgarianus group, but 

 may be distinguished by its being more inflated, less rayed, and in having a less 

 polished surface in the adults than Edgarianus. The specimen figured is the 

 largest of the five. 



Unio vesicularis. pi. 12, fig. 34. 



Testa Isevi, elliptica, inflata, valde insequilaterali, postice et antice rotundata ; valvulis crassiusculis, 

 antice crassioribus ; natibus prominulis ; epiderrnide tenebroso-oliva, obsolete radiata ; dentibus 

 cardinalibus parvis, sulcatis, in utroque valvule duplicibus ; lateralibus sablongis, lamellatis sub- 

 rectisque ; margarita albida et valde iridescente. 



Shell smooth, elliptical, inflated, very inequilateral, rounded behind and before; 

 valves a little thick, thicker before; beaks slightly prominent; epidermis dark olive, 

 obscurely rayed ; cardinal teeth small, sulcate and double in both valves ; lateral 

 teeth rather long, lamellar and nearly straight; nacre whitish and very iridescent. 

 Proc. Acad. Nat. Sci., 1872, p. 156. 



jffa&.— Lake Ocheechobee, Florida, Dr. Budd and C. M. Wheatley. 



My cabinet, and cabinet of Mr. Wheatley. 

 Diam. -5, Length -7, Breadth 1-3 inch. 



Shell smooth, elliptical, inflated, very inequilateral, rounded behind and before ; 

 substance of the shell a little thick, thicker before; beaks slightly prominent; liga- 

 ment rather long and thin ; epidermis dark olive, obscurely rayed, with distant 

 marks of growth ; umbonial slope rounded ; posterior slope narrow-elliptical ; car- 

 dinal teeth small, sulcate, somewhat compressed and double in both valves ; lateral 

 teeth rather long, lamellar and nearly straight; anterior cicatrices distinct, small 

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



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