﻿UNITED STATES. 209 



Remarks. — I owe to the kindness of Mr. Downie a number of this interesting 

 species. It is near to Lecontianus (nobis), but is less transverse and more inflated 

 It is also near to Downiei, but not so oblique. It is generally purple in the nacre. 

 Three out of fourteen were salmon color in the. cavity of the shell, surrounded by 

 purple; none were white. There are two slight emarginations on the posterior 

 margin, caused by the two raised lines, which, passing from the beaks, terminate here. 

 The dark rays, which are rather obscure, are broad and more discernible on the 

 anterior half of the valves. The strias on the inferior portion are rough, and the 

 surface disposed to be in large furrows. 



Unio Chattanoogaejstsis. PI. 25, fig. 90. 



Testa laevi, obliqua, cuneata, subinflata, antice 1 decisa ; valvulis percrassis, antice* crassioribus ; natibus 

 elevatis, incuryatis, fere terminalibus ; epidermide luteo-oliva, transverse yirido-vittata ; dentibus 

 cardinalibus subgrandibus, compressis et erectis ; lateralibus sublongis, cra'ssis subcurvisque ; rnargarita 

 argentea et iridescente. 



Shell smooth, oblique, wedge-shape, inflated before and compressed behind, truncate 

 before ; valves very thick, thicker before ; beaks raised, incurved, almost terminal ; 

 epidermis yellowish olive, with green transverse bands ; cardinal teeth rather large, 

 compressed and raised ; lateral teeth rather long, thick and somewhat curved ; nacre 

 silvery white and iridescent. 



Proc. Acad. Nat. Soi., 1858, p. 166. 



Hab. — Chattanooga, Tenn., T. Stewardson, M. D. Etowah River, Rev. G. White. 

 Coosawattee and Oostenaula Rivers, Bishop Elliott. 



My cabinet and cabinets of Bishop Elliott and Rev. G. White. 

 Diam. *9, Length 1*3, Breadth 2*1 inches. 



Shell smooth, oblique, wedge-shape, inflated and truncate before and compressed 

 and dilate behind ; substance of the shell very thick, thicker before ; beaks raised, 

 incurved, almost terminal ; ligament rather short, thick and light brown ; epidermis 

 yellowish olive, with green transverse bands on the upper part of the disk, striate 

 below, and usually with somewhat distant marks of growth ; umbonial slope flattened ; 

 posterior slope with a single impressed line on each valve ; cardinal teeth somewhat 

 large, compressed, raised, striate, almost terminal, direction nearly parallel with the 

 lateral tooth ; lateral teeth rather long, thick, enlarged at the end and somewhat 

 curved; anterior cicatrices distinct and deeply impressed; posterior cicatrices distinct 

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

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

 and rounded ; nacre silvery white and iridescent. 



Soft parts. — Branchial uterus . Could find no ova in the branchiee or the 



ovarium of the only specimen I received. Branchiee small, inner ones rather the larger, 

 apparently free nearly the whole length of the abdominal sack. Mantle very thin. 



