FRESH WATER AND LAND SHELLS. ?<) 



naturalist, Dr. Griffith, or myself. By an inexperienced eye it might be considered as an 

 aberrant form of U. complanaius, but in outline it is really more like Margaritana margari- 

 tifera. It differs from complanatus in being more transverse, in being without rays, in the 

 remarkable lines of growth, and in its teeth. The lateral tooth enlarges suddenly from 

 the small plate near the cardinal tooth and curves upwards; in the left valve the inferior 

 portion of the lateral tooth is very much thickened. Two of the specimens before me are 

 perfectly white — one is tinged with purple on the posterior portion — the fourth is purple 

 >ver tin' v>hule nacre. 



Unio Pallescens. PI. VII. Fig. 20. 



Tenia hi'vi, ellipticd, valde injlatd: vulvidis subcrassis ; nutibus subprominciitibxs: rpidt rmidt pallido-luted , 

 tlentibus cardinaHbits magnis, compressis erectisijxc; htteralibus longis curvisque; Margarita (dim. 



Shell smooth, elliptical, much inflated; valves rather thick; beaks slightly prominent; epidermis pale-yellow; 

 ■ardinal teeth large, compressed and erect ; lateral teeth long and curved ; nacre white. 



Hal). Tuscaloosa, Alabama. 13. W. Budd, M. D. 



Cabinet of Dr. Budd. 

 Diam. 1.4, Length .2, Breadth 3.1 inches. 



Shell smooth, elliptical, much inflated: substance of the shell rather thick; beaks slightly 

 prominent; ligament long and large; epidermis pale-yellow colour, striate and somewhat 

 shining, apparently without rays; cardinal teeth large, compressed, elevated, pointed and 

 double in both valves; lateral teeth long, lamellar, and curved; anterior cicatrices distinct; 

 posterior cicatrices distinct; dorsal cicatrices placed across the cavity of the beaks; 

 i -;i\ ity of the shell deep and large; cavity of the beaks small and rounded ; nacre silvery- 

 white and iridescent. 



Remarks. — A single and not very perfect specimen of this species is before me. It 

 seems to be allied, on one side, to U. luteolus, Lam., and, on the other, to V. stramineus, 

 Conrad. A large portion of the disks being eroded from the beaks downwards, the cha- 

 racters of the younger growths cannot be observed. Its teeth are very much like those 

 of luteolus, but I do not think this specimen could, with propriety be considered to belong 

 to that species. 



l.MO CALIGINOSUS. PI. VII. Fig. 21. 



'/'■■in Item, ellipticd, sxbcompressd ; valvulis svbtenuibus ; natibus prominulis, ad apicem undulatis; epidm 

 nude lenebroso-fi'sra ; dentibus cardinalibus compressis, efevatis; lateralibus longis siibcurvisi/iu ,- margaritd 

 albd ri iridescente. 



Shell smooth, elliptical, rather compressed; valves rather thin; beaks somewhat prominent, undulated at the 

 beaks; epidermis dark-brown; cardinal teeth compressed, elevated ; lateral teeth long and somewhat curved; nacre 

 white and iridescent. 



llali. Red River, at Uexandria, Louisiana. J. Hale. .M.D. 



My cabinet and cabinet of Dr. Hale. 

 Diam. .8, Length 1.2, Breadth 2.2 inches. 



Shell smooth, elliptical, rather compressed, obtusely angular behind; substance of the 

 shell lather thin, Blightlj thickened before; beaks somewhat prominent and minutely un- 



