FHF.SII WATER AND LAND SHELLS. 289 



Remarks. — This species is nearly allied to A. tetragona, (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. Shaeffer, marked " Missouri," is 

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



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

 and I name this one after him. 



Anodonta Linx.t.na. PI. XXVII. Fig. 51. 



Testa laevi, rotundatd, valde in/laid, subxquilaterali, postice obtuse angulatd; valvulis sublenuibus; 

 natibus protnintntibua, ail apices rug (U ; epidermide luteo-viridi, nitidd, striata, obsolete radiatd : 



aritd salmonis colore tinctd it iridescente. 



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

 beaks prominent ami 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. 1.9, 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; pallcal cicatrix scarcely visible; cavity of the 

 .-hell 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 Anodonta I have seen from our country. It 



isl 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 white. The epidermis is rough with stria-, 

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



i( a is allied to .1//. globosa, (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 



:i in ( 'incinnati, nearly two years since, Mr. J. Clarke gave me a suite of a species of • inodonta which 

 hi' considers to be the true edentula of Mr. Say, described in "The Disseminator." They were taken from the 

 river Ohio, mar that city, and are not found in Mill < , near by, where the hi abounds. I!*' 



that ihey differ in the beak", and in the oullinc they appear to mc to differ very much, — the Ohio shell ' 

 very wide and oblong, while the Mill Creek shell is oval, and usually largir. The latter is also more ray< d. 



