GASTROPODA— TROCHOTURBINID&. 671 



Small, high-spired, shoulder concave, lower peripheral carina 

 obsolete. In T. salteri U. and S. the spire is still higher (less 

 embracing), and the lower peripheral carina almost as strong as 

 the upper. 



Trenton of Minnesota (7! salteri) ; Utica of Cincinnati region (T. 

 nitidum). 



205. T. (Gyronema) pulchellum Ulrich and Scofield. (Fig. 

 928, e, f.) Ordovicic. 

 Small, rather high-spired, with apical angle about 85 . In the 



body whorl occurs a spiral on the shoulder near the suture, 

 between the two peripheral ones, and five or six on the basal por- 

 tion of the whorl. Intercarinal space convex. 

 Black River of Minnesota and Kentucky. 



206. T. (Gyronema) duplicatum U. and S. (Fig. 928, g y h.) 



Ordovicic. 



Larger than preceding, with closed umbilicus, carina fainter, 

 shoulder carina often obsolete, central peripheral one sometimes 

 double or with an additional one ; lower 6 or 7 faint. 



Black River of Wisconsin, Minnesota, and Illinois. 



LXV. Anomphalus Meek and Worthen. 

 Shell naticoid, small, but without umbilicus ; low spire and in- 

 complete aperture. Carbonic. 



207. A. rotulus M. and W. (Fig. 929.) Carbonic. 





Fig. 929. Anomphalus rotulus, side Fig. 930. Anomphalus {Protospirialis) 



and under views, X 2 /^« (After Meek minulissima, X 5- (After Clarke*) 

 and Worthen, 111., V.) 



Small, depressed, with scarcely visible spire ; volutions increas- 

 ing rather rapidly ; aperture transversely suboval ; surface smooth. 

 Coal measures of Illinois, Iowa, and Missouri. 



208. A. (Protospirialis) minutissima Clarke. (Fig. 930.) 



Devonic. 



