NEW FRESH WATER AND LAND SHELLS. 21 



cardinalibus parvis, obliquis, compressis sublaniellatisque ; lateralibus prselongis subrectisque ; margarita 

 salmonis colore tincta et valdii iridescente. 



Shell smooth, elliptical, subcompressed, subemarginate, very inequilateral, obtusely 

 angular behind ; valves rather thin, beaks small, somewhat prominent and undulate ; 

 epidermis yellowish olive and polished ; cardinal teeth small, oblique, compressed and 

 somewhat lamellar ; lateral teeth very long and nearly straight ; nacre salmon colored 

 and very iridescent. 



Proc. Acad. Nat. Sci. Vol. 8, p. 94. 



Hab. — Cape of Good Hope. Mr. E. Verreaux. 



My cabinet, cabinets of Mr. Verreaux, Paris, and W. A. Haines, New York. 

 Diam. -G. Length -8, Breadth 11 inch. 



Shell smooth, elliptical, subcompressed, slightly emarginate at base, very inequi- 

 lateral, obtusely angular behind ; substance of the shell rather thin, thicker before ; 

 beaks small, somewhat prominent, with numerous small undulations at the tips and on 

 the posterior slope ; lines of growth few, distinct and distant; ligament rather long 

 and "slender; epidermis yellowish olive, very smooth and shining; umbonial slope 

 subangular ; cardinal teeth small, oblique, compressed, somewhat lamellai", double in 

 both valves ; lateral teeth very long, very slightly curved, single in the right and 

 double in the left valve ; anterior cicatrices distinct ; posterior cicatrices distinct ; 

 dorsal cicatrices placed on the under posterior part of the cardinal teeth ; cavity of the 

 shell rather shallow ; cavity of the beak rather shallow and subangular ; nacre light 

 salmon colored and' very iridescent. 



Remarks. — This species was procured by Mr. E. Verreaux while in South Africa, 

 and' given to me while in Paris, in 1853. Subsequently Mr. Haines submitted 

 specimens to me from the same habitat. The anterior muscular cicatrices present an 

 unusual character in the three, being remarkably distinct. The undulations of the 

 beaks are beautifully distinct, numerous and regular, and are delicately arranged also 

 on the posterior slope as well as over a large portion of the bfeaks. In outline and 

 general character it is allied to U. Bataviw, Lam., and more particularly to that variety 

 named U. Carynthiacus by Ziegler. In outline and general form Africanus approaches 

 Verreauiamis, herein described, but it differs entirely in size and in the surface, being 

 smooth and polished, while Verreauiamis belongs to the sulcate division, and is 

 usually twice the size ; they therefore cannot be confounded. It approaches also to 

 U. Gaffe}', Krauss, but differs much from the figure given by him, (Sudafrik Moll., 

 p. 18.) It much more resembles a specimen given to me by the late Prof E. Forbes, 

 from South Africa, under that name. 



• Unio Verreauianus. PI. 27, lig. 10. 



Testa .sulcata, oblonga, inflata, subcmarginata, subscquilaterali, postic6 obtuse angulata ; valvulis crassis ; 

 natibus parvis, subprominentibus undulatisquc ; cpidermidc lutco-brunnca, striata ; dcntibus cardinalibus 



