XVI 



solida^ Lea. undulata. Say. 



torquata, Lea. Vanuxemiana, Lea.* 



" Genus Leptoxis, Eafinesque (i, 307.) 



Shell ovate or globose, solid, subperforate ; spire very sliort? 

 aperture oval ; inner lip with a posterior eallosit}^, often ante- 

 riorly callous and produced ; outer lip thin, sinuous with a 

 posterior, ascending canal. 



S3'n. Anculotiis, Say, Anrulosa, Swains., Ancylotus, Herm. 



Ex. L. 2>i'ci:rosa, Say, t. 32, fig. G, a, b. 



The species of this genus are peculiar to the North American 

 rivers ; the spire of the shell has a truncated, eroded apex, and, 

 in the typical species, the shell is solid and subglobose, with 

 the aperture simple in front. 



ahrupta^ Lea. inlxiJa^ Lea. 



angulata, Conr. p?'s?<m, Hald. 



crassa, Hald. pUcata, Conr. 



Jlammata, Lea. prcerosa, Say. 



fuUginosa, Lea. ^nimilis^ Conr. 



fusca, Hald; rubiginosa, Lea. 



fusiformis, Lea. squalida, Lea. 



gibbosa, Lea. subglobosa, 8ny. 



globida, Lea. tceniata, Say. 



Griffithsiana, Lea. tintiniiabidum, Lea. 



Hildrethiana, Lea. trivittatits, DeKay. 



Integra, Say. Troostiana, Lea. 



melanoides, Conr. tnrgida, Hald. 



J^ickliniana, Lea. variabilis, Lea. 



nigrescens, Conr. virgata, Lea. 



obtusa, Lea. viridis, Lea.f 

 picta, Conr. 



" Subgenus Nitocris, H. & A. Adams (i, 308.) 



Shell thin, subglobose ; whorls angulated, often carinate ; 

 inner lip subtruncate, or ending in a tubercle. 



carinata, Lea. dilatata, Conr. 



costata, Lea. dissiinilis, Say. 



dentata, Couth. ehena, Lea. 



*Here we find shells belonging to several groups, as jmmila, Lea, 

 alveare, Conr., and torquata, Lea, to StropJiobasis ; lima, Conr., and 

 solida, Lea, to Lithasia ; tindidata, Say, to Plevrocera. Hoeydei, Lea, 

 was never described. Can it be intended for Hi/dei, Conr. ? The spe- 

 cies arc generally, however, the ponderous Gouiobases of Northern 

 Alabama. 



tin the species of this genus there are several errors, some quite 

 elongated forms being included ; also, a species of Lithasia. 



