64 NEW UNIONIDJE, MELANID^, ETC., 



posed to be salmon color. Both the specimens gap anteriorly, and the basal and 

 anterior margins are reddish at the edge of tlie nacre. 



Spatha Natalensis. pi. 20, fig. 58. 



Testa subsulcata, oblonga, compressa, subnitida, valde inssquilaterali, ad latere planulata, antice rotunda, 

 postice rotundata ; valvulis crassiusculis, antice aliquanto crassioribus ; natibus vix prominulis, ad 

 apices minute undulatis ; epidermide tenebroso-rufo-fusca, eradiata ; margarita purpurea et valde 

 iridescente. 



Shell subsulcate, oblong,' compressed, somewhat shining, very inequilateral, 

 flattened at the side, round before and rounded behind ; valves somewhat thick, 

 slightly thicker before ; beaks slightly prominent and minutely undulate at the tips ; 

 epidermis dark reddish brown, without rays ; nacre purple and very iridescent. 

 Proc. Acad. Nat. Sci., 1864, p. 113. 



Hah. — Umpingave River, Port Natal, South Africa, Kev. J. McKen. 



My cabinet and cabinet of the Academy of Natural Science. 

 Diam. "9, Length 1-7, Breadth 3"5 inches. 



Shell subsulcate, oblong, compressed, somewhat shining, very inequilateral, 

 flattened at the sides, round before and rounded behind ; substance of the shell some- 

 what thick, slightly thickened before ; beaks very slightly raised and minutely undu- 

 late at the tips ; ligament long, rather thin, dark brown and nearly concealed ; 

 epidermis dark reddish brown, without rays, with distant marks of growth ; umbonial 

 slope flattened and without any angle ; posterior slope very narrow and long, and 

 with three rather broad lines on each valve from the tip to the posterior margin ; 

 anterior cicatrices distinct, very large and well impressed ; posterior cicatrices dis- 

 tinct, slightly impressed, the inferior very large ; dorsal cicatrices rather large, well 

 impressed and placed near to the centre of the cavity of the beaks ; cavity of the 

 shell very shallow and very wide ; cavity of the beaks very small, scarcely observa- 

 ble ; nacre purple and very iridescent. 



Remarhs. — Several specimens of this new Spaiha were given to the Academy by 

 the Eev. J. McKen, connected with the Missionary establishment at Port Natal. On 

 first examining it I supposed it might be a strong variety of /S. rubens {Iridina Lam.,) 

 being far removed from the habitats of the Senegal and the Nile, but that is a larger 

 shell and much heavier, as well also differing in being elliptical. The undulations of 

 the tips of the beaks are also in ruhetis still more minute and can only be seen at the 

 very tips or points. The epidermis is also smooth and green, while in Natalensis it is 

 dark reddish brown and sulcate. In this species the muscular scars are all large, as 

 is usual in the Spatlice and Iridince, and the posterior great scar, has a ridge on 

 each side of the line of increment along the line of displacement. All the specimens 



