FRESHWATER AND LAND SHELLS. 77 



Anodonta Nuttalliana. Plate XX. fig. 62. 



Testa alata, elliptica, compressa, glabra, inceqidlaterali ; valvulis tenuibus connatisque ; 

 natibus compressis, ad apices undulatis ; epidermide politd ; marganta alba. 



Shell winged, elliptical, compressed, smooth, inequilateral; valves thin and connate ; 

 beaks compressed and undulated at the tip; epidermis polished ; nacre white. 



Hab. Wahlamat, near its junction with the Columbia River. Pro- 

 fessor Nuttall. 



My Cabinet. 



Cabinet of Professor Nuttall. 



Diam. -7, Length 1'5, Breadth 2-3 inches. 



Shell winged, elliptical, flattened on the side and enlarged on the 

 umbonial slope, subemarginate at base, smooth, inequilateral ; substance 

 of the shell thin, the valves being connate over the ligament ; beaks 

 compressed and undulated at the tip ; umbonial slope furnished with 

 several impressed lines; epidermis smooth and polished, having a dark 

 broad band at the line of growth near the margin ; cicatrices scarcely 

 visible ; cavity of the shell very small ; cavity of the beaks very small ; 

 nacre white. 



Remarks. — I am greatly indebted to the learned and enterprising 

 traveller. Professor Nuttall, for this and two other species of Anodonta^ 

 which come from an entirely new locality. The rivers beyond the 

 Rocky Mountains had not before been examined in regard to their 

 mollusca, and we have now for the first time the pleasure of seeing a 

 specimen of this family from these waters. The Wahlamat is the river 

 known in Lewis and Clark's Travels under the name of Multnoma. 



This species has some resemblance to Jin. Benedictensis (nobis), but 

 may be distinguished by its flattened sides and dark band, as well as its 

 polished surface. 



VL — U 



