FRESH WATER AND LAND SHELLS. 281 



Whether there be undulations at the tips it is impossible to say. In outline, it is some- 

 what like U. Ravenelianus, (Nobis,) but it is less oblique and less compressed. It is also 

 allied to U. nucleopsis, Con., but that is quite round in the outline, while the former is 

 rather oblique. It is also much more compressed. 



I dedicate this species to M.Troschel, who has done much in the anatomy of this family. 



Unio Keinerianus. PI. XXIII. Fig. 40. 



Testa tuberculoid, subrotundatd, subinflatd, subequilaterali; valvulis crassis; nations prominent ibus, sub' 

 medialis; aridermide luteold, substriata; dentibus cardinaliuus grumlibus, granulatii crassisque; lateralibus 

 brews, crassis subrectisque; margaritd alba et iridescente. 



Shell tuberculate, subrotund, somewhat inflated, subequilaieral ; valves thick, beaks prominent, submedial ; 

 epidermis yellowish, somewhat striate; cardinal teeth large, granulate and thick; lateral teeth short, thick and 

 nearly straight; nacre white and iridescent. 



I lab. Coosa wattec river, Murray county, Georgia, Dr. Boy kin. 

 My cabinet. 

 Diam. .7, Length 1.1, Breadth 1.3 inches. 



Shell sparsely tuberculate, subrotund, somewhat inflated, nearly equilateral, rounded 

 behind; substance of the shell thick, rather thinner behind; ligament short and rather 

 thick; epidermis yellowish, somewhat striate near the margin, with very close marks of 

 growth; posterior slope wide and but slightly raised ; umbonial slope rounded; cardinal 

 in th large, granulate, thick, double in the left and somewhat trifid in the right valve; 

 lateral teeth short, thick, nearly straight, far removed from, and in a direction far above 

 the cardinal tooth, leaving a large plate between the two teeth; anterior cicatrices dis- 

 tinct: posterior cicatrices distinct; dorsal cicatrices in a row under the cardinal teeth; 

 palleal cicatrix well impressed; cavity of the shell moderately deep; cavity of the beaks 

 deep and angular; nacre white and iridescent. 



Remarks. — I very much regret that I have not better specimens of this species. The 

 four before me are all worn in the beaks more or less, and two of them are quite old and 

 eroded. The two younger ones only have rays. The older of these, here figured, has a 

 broad, green ray over the middle and anterior portion of the disk, and two small ones on 

 the posterior Blope. On the youngest specimen, about one-fourth grown, there is no 

 tubercle; on the others they are very few and very small, and placed towards the mar- 

 gin. These are bo small as scarcely to deserve the name. This species belongs to the 

 group of which V. pustulosus, (Nobis,) may be considered the type. It diners from thai 

 shell in being rounder and having fewer tubercles, in being less angular behind and more 

 rounded before. It is allied to U. Schoolcraflensis, (Nobis,) but that is more quadrate, 

 having quite a compressed carina, but resembles it in baving few tubercles. The two 

 old< - imens arc slightly impressed before the umbonial Blope and are subangular 



behind. 



I dedicate it to Mr. !,.('. Keiner, the author of "Species General et Icon. Coquil. 

 \ i mi. ■-." 



