UNITED STATES. 21 



teeth are thicker and not so oblique. The specimen figured has more and broader 

 rays than either of the others. The rays in all the four specimens are disposed to be 

 more or less interrupted, but not strikingly so. This species is also somewhat allied 

 to Cumherlandianus (nobis), but it is a little larger, more inflated and not quite so 

 transverse as that species. The undulations of the beaks are somewhat eroded at 

 the tips, but enough remain in the younger specimens to denote that they consist of 

 two or three rather large irregular nodulous folds. 



Unio penicillatus, pi. 23, fig. 85. 



TcstiV postic6 plicata,, subclliptica, subinflata, postice subbiangulata,, iu»quiliitcrali ; valviili.s crassiusculis, 

 antic6 crassioribus ; natibus subpromincntibus, ad apices miuuto undalatis ; cpiJcnuiJo lutcola, raJiis 

 pcnicillatia iiidutis, polita; dcntibus cardinalibus crassiusculis, crenulatis, subpyramidatis ; lateralibus 

 sublongis, subcrassis subrcctisque ; margariti vcl alba vol rosea vel salmouis colore tincta et vald6 

 iridescento. 



Shell plicate behind, subelliptical, rather inflated, biangular behind, inequilateral ; 

 valves a little thick, thicker before ; beaks a little prominent and minutely undulate 

 at the tips; epidermis yellowish, polished and covered with pencilled raj-s; cardinal 

 teeth somewhat thick, crenulate and rather pyramidal; lateral teeth long, somewhat 

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

 Proc. Acad. Nat. Sci., 1857, p. 171. 



Ilah. — Chattahoochee, near Columbus, Georgia, Dr. Boykin, and near Atlanta, 

 Bishop Elliott. Flint River, near Albany, Georgia, Bishop Elliott and Rev. G. White. 



My cabinet and cabinets of Bishop Elliott and Mr. White. 

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



Shell plicate behind, ellipsoidal, rather inflated, somewhat biangular behind, inequi- 

 lateral, substance of the shell a little thick, thicker before ; beaks a little prominent, 

 with numerous small undulations at the tips ; ligament rather short, thin and dark 

 brown; epidermis yellowish, polished and covered with interrupted pencilled rays, 

 which are more conspicuous on the posterior half; umbonial slope slightly raised and 

 rounded ; posterior slope rather narrow and covered with small, rather oblique and 

 slightly curved folds; cardinal teeth somewhat thick, crenulate and rather pyramidal ; 

 lateral teeth long, somewhat thick and straight; anterior cicatrices all three distinct 

 and well impressed ; posterior cicatrices distinct ; dorsal cicatrices under the plate 

 behind the cardinal tooth ; cavity of the shell rather shallow ; cavity of the beaks 

 shallow and rounded ; nacre either white, rose or salmon color, but rarely rose color. 



Soft parts. — Branchial titerus occupies about two-thirds the breadth of the outer 

 branchia?, and has about twenty large ovisacks which are very much enlarged below, 

 and seem at first sight to extend the whole breadth; they extend much below the 

 line of the branchial leaf.'-^ BrancJdce rather large, rounded below, inner one the larger, 



♦Till- Piipcimon fiom Flint River lia.l only the middlo of the l.iaiuliia occupieil l.y 5 or G ovisacks. 



