FRESH WATER AND LAND SHELLS. 45 



Remm-ks. — This species is nearly allied to A. tctragona, (Nobis,) but seems to me too 

 distinct to be considered the same. The outline is much the same, but the tuberculous 

 swellings under the beak are more enlarged than in that species. The umbonial angle is 

 also more sharp. There are two specimens before me, both of which have beautiful sal- 

 mon-coloured nacre. A third specimen, also from Mr. Shaefler, marked " Missouri," is 

 somewhat like the others, but approaches more to some of the varieties of areolalus, Swain.* 



I owe this and several other fine shells to Mr. Shaeffer, an ardent collector of Cincinnati, 

 and I name this one after him. 



Anodonta Linn^na. pi. XXVII. Fig. 51. 



Tesld l:em, rolundata, valde injlalu, siibxquilatcrali, post ice obtuse angulalu; valvidls suhtemiibus ; 

 natibiis prominent ibus, ad apices riigoso-iindulalis ; epidermide luleo-viridi, niiidd, striata, obsolete radiuta; 

 margaritd salmonis colore tinctd ct iridescente. 



Shell smooth, rotund, very much inflated, nearly equilateral, obtusely angular behind; valves rather thin; 

 beaks prominent and rugosely undulate at the tip; epidermis yellowish-green, shining, striate, obscurely rayed; 

 nacre salmon-coloured and iridescent. 



Hab. Lake Concordia, Louisiana, Mr. C. M. Wheatley. 

 My cabinet and cabinet of Mr. Wheatley. 

 Diam. L9, Length 2.8, Breadth 4.1 inches. 



Shell smooth, rotund, much inflated, nearly equilateral, obtusely angular behind ; very 

 much inflated and rounded at the umbones, curved on the dorsal line; substance of the 

 shell rather thin; beaks prominent, inflated, and rugosely wrinkled at the tip; ligament 

 rather short and somewhat thick; epidermis yellowish-green, shining, rather roughly 

 striate, obscurely rayed and very dark on the posterior slope; posterior slope broad, 

 short, rather flattened, and very rugose; umbonial slope angular; anterior cicatrices con- 

 fluent; posterior cicatrices confluent; dorsal cicatrices placed near to the edge, some dis- 

 tance anterior to the point of the beaks; palleal cicatrix scarcely visible; cavity of the 

 shell very deep and rounded; cavity of the beaks deep and rounded; nacre beautifully 

 salmon-coloured, rich, and iridescent, leaving a very broad border round the margin. 



Remarks. — This is the finest species of Aiiodonta I have seen from our country. It 

 is most beautifully coloured in the nacre, which is exceedingly brilliant. A single speci- 

 men only is before me, and this is' somewhat fractured. The margin is very uncom- 

 monly broad, without any pearly nacre, and Avhite. The epidermis is rough with stria?, 

 and yet it looks rich and pleasing. The green rays are broad and iridescent. This 

 species is allied to An. glohosa, (Nobis,) from Mexico; but it differs much in the smooth- 

 ness and polish which the latter shell has. The beaks are more medial and the margin 



* When in Cincinnati, neaily two years since, Mr. J. Clarke gave me a suite of a species o( .Inodonia which 

 he considers to be the true edcntida of Mr. Say, described in "The Disseminator." 'I'hcy were taken from the 

 river Ohio, near that city, and are not found in Mill Creek, near by, where the areolatiis abounds. He says 

 that they difl'er in the beaks, and in the outline they appear to me to difier very much,— the Ohio shell being 

 very wide and oblong, while the Mill (^reek shell is oval, and usually larger. The latter is also more rayed. 



