24 TORINIA OMALAXIS. 



Subgenus EPISCYNTA, Morch, 1875. 

 T. INORNATA, d'Orb. PL 6, figs. 32, 33. 



Shell convex ; whorls 5, smooth, glass}^ white, shining, roundly 

 carinate at the periphery; base convex; umbilicus moderate, 

 smooth ; aperture oval. Diam. 3 mill. 



St. Thomas, West Indies. 



The smoothness of the shell, its glassy appearance, its minute- 

 ness and the simple umbilicus are perphaps enough to rule this 

 subgenus out of the family. 



Genus OMALAXIS, Desh., 1830. 

 0. PERNAMBUCENSIS, Watson. PL G, figs. 35, 36. 



Shell discoidal ; whorls about four, contiguous, except the last 

 which is slight!}" dissolute, convex, obsoletely spirally threaded, 

 longitudinally ribbed ; color white, glassy or porcellanous ; 

 umbilicus very wide, exposing all the whorls ; aperture oval, lip 

 not in contact with the whorl above. Diam. 2'5 mill. 



Pernambuco. 

 0. NOBILIS, Yerrill. PL 6, fig. 31. 



Shell planorbiform, upper surface nearly flat, base very con- 

 cave ; whorls 5, nearly quadrangular, the two peripheral angles 

 strongly granosely carinate, peripheral area spirally ribbed, sur- 

 face of the shell with radiating, elevated growth-lines ; color 

 pale chestnut, irregularly and indistinctly banded with whitish 

 chestnut ; base spirally striated ; aperture trapezoidal with the 

 outer corners angular and the inner corners rounded. Opercu- 

 lum thin, horny, multispiral, slightly concave. Diam. 11 mill. 



Chesapeake Bay. 



Un figured Species. 

 0. LIRATA, Yerrill. Newport, R. I. 



