68 • NEW UNIONID/E OF THE UNITED STATES. 



My cabinet and ca))inets of Mr. Thornton and Mr. White. 

 Diara. 1-3, T.ength 1-8, Breadth 2 inches. 



Shjell subnodulous, obHque, subtriangular, very inequilateral, sulcate on the sides ; 

 substance of the shell thick, thicker before ; beaks erect, swollen ; ligament short, 

 thick and dark brown ; epidermis yellowish or green, with numerous capillary rays 

 over nearly the whole disk and with well marked lines of growth ; umbonial slope 

 raised, rounded and subnodulous ; posterior slope very oblique, somewhat compressed ; 

 cardinal teeth rather large, crenulate, double in both valves ; lateral teeth very thick, 

 crenulate, short and somewhat curved ; anterior cicatrices distinct, rather small and 

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

 cicatrices placed under the plate above the cavity of the beaks ; cavity of the shell 

 rather shallow and wide ; cavity of the beaks deep and obtusely angular ; nacre white 

 and iridescent. 



Remarhs. — A number of specimens are before me, varying very much in form and 

 color of the epidermis. The nacre of the specimens I have seen is of a clear white. 

 They may be found purple, as the kindred species perjylextis are sometimes. None of 

 the specimens had perfect beaks. It belongs to the group of which perplexus is the 

 type. It usually has small swellings at each stage of growth on both sides of the 

 oblique furrow. The female enlargement is like that in Rancjianus (nobis) in form, 

 and in being of a light color. It is between perplexus and Rangianus. In some speci- 

 mens the rays are very numerous, while othei^s have few. The palleal cicatrix is 

 emarginate. The figure is from a male. 



Unio Florentinus. pi. 5, fig. 213. 



Testa IjEvi, elliptica, subaequilaterali, ad latere paulisper planulata; valvuHs crassis, antice crassioribus ; 

 natibus tumidis, ad apices undulatis ; epidermide rufo-olivaceii, valde radiata; dentibus cardinalibus 

 subgrandibus, conicis, crenulatis, in utroque valvule duplicibus; lateralibus curtis, crassis subcurvisque; 

 margarita alba. 



Shell smooth, elliptical, nearly equilateral, slightly flattened at the sides ; valves 

 thick, thicker before ; beaks swollen, undulate at the tips ; epidermis reddish olive, 

 much rayed ; cardinal teeth rather large, conical, crenulate, double in both valves ; 

 lateral teeth short, thick and somewhat curved ; nacre white. 

 Proc. Acad. Nat. Sci. 1857, p. 83. 



Hah. — Florence, Alabama ; Kev. G. White. Cumberland River, Tenn. ; Drs. Troost, 

 Edgar and T. C. Downie, Esq. 



My cabinet and cabinets of Mr. White and Mr. Downie". 

 Diam. "7, Length -9, Breadth 1-3 inch. 



Shell smooth, elliptical, nearly equilateral, slightly flattened on the sides; substance 

 of the shell thick, thicker before; beaks small, undulate at the tips; ligament very 



