HELIX. 9 



H. SIMILIS, C. B. Adams. PL 1, figs. 23, 24. 



Perforate, depressed, rather thin, somewhat distantly strinlate, 

 shining, diaphanous, whitish, spire scarcely convex, the apex 

 submucronate ; whorls 6, narrow, slightly convex, the last later- 

 ally subcompressed, base a little excavated. Diam. 13 mill. 



Jamaica. 

 H. HOLLANDI, C. B. Adams. PL 1, figs. 25, 26. 



Differs from the preceding species in the whorls being more 



depressed, base plane, aperture wider. Diam. 11 mill. 



Jamaica. 



H. AMBIGUA,,C. B. Adams. PL 1, figs. 27, 28. 



Differs from H. similis in having a more elevated spire, colu- 

 mella less oblique, anterior part of the lip directly transverse, 

 umbilicus smaller. Suture deeper than in H. similis or H. Halde- 

 maniana, between which this shell is in most characters inter- 

 mediate. Diam. 11 '5 mill. 



Jamaica. 



H. BREVIS, C. B. Adams. PL 1, fig. 29. 



Narrowly umbilicated, depressed, subdiscoidal, thin, smooth, 

 shining, whitish ; spire scarcely convex ; whorls 4^, flattened, 

 slowly increasing, the last depressed, base subplanulate. 



Diam. 3*75 mill. 



Jamaica. 



H. CIRCUMFIRMATA, Redfield. PL 1, fig. 30. 



Umbilicated, conoidally depressed, thin, lightly obliquely 

 striated ; fulvous corneous, with irregular light chestnut striga- 

 tions ; suture impressed ; whorls 7^, slowly increasing, the last 

 with angulated periphery and more convex base ; aperture with 

 an acute white spiral lamina below the periphery, visible through 

 the shell, columella with a spiral callus. Diam. 10*5 mill. 



Bermuda. 

 H. DISCREPANS, Pfr. 



Differs from the preceding species in being more solid, the 

 spire less elevated, the peripheral carina more acute, a basal 

 interior carina reaching the margin of the aperture, and the 

 columella subdentate within near its insertion. Diam. 10'25 mill. 



Bermuda. 

 Unfigured. 



