158 Desertions of New Species of Ancylus and Ancuhsa. 

 3. Cycloxtoma clis tor turn. 



Plate A T . Figs. 5-8. 



'J', umbilicata, distorta, globosa, conica, longitudinaliter ininutissime 

 striata, alba; spira conica; sutura valde impressa, simplici ; anfr. 5 con- 

 vexis, ultimo inflato, prope aperturam constricto ; apertura circulari ; 

 perist. simplici, incrassato-expansiusculo. 



Opera, ? 



Diam. maj. 12, min. 10, alt. 11 mill. Ap. 5 mill. diam. 



Habitat. — Siam. 



Closely allied to C. gibbum, but differs essentially; being 

 larger, the last whorl more inflated, lip more broadly reflected, 

 and the striae finer and more numerous. 



4. Vitrinsi Sianiensis. 



T. depresso-globosa, tenui, laevigata, pallide cornea; spira, vix ele- 

 vata ; anfr. 3 celeriter accrescentibus, ultimo inflato ; apertura obliqua, 

 eoarctata, rotuudato-quadrata ; perist. simplici, margiue columellari 

 arcuato. 



Diam. maj. 30, min. 24, alt. 15 mill. 



Habitat. — Siam. 



Note.— Together with the above species, I have received Helix distincta Pfr., 

 the precise locality of which appears hitherto to have been doubtful. 



XXIV. — Descriptions of New Species of Ancylus and Ancu- 

 losa, from the Western States of North America. 



By John G. Anthony, Esq., of Cincinnati, Ohio, Corresponding Member. 

 Head February 27, and October 22, 1S55. 



Ancylus elatior. 



Plate V. Fig. 20-21. 



Shell very much elevated, ovate ; lines of growth distant, 

 conspicuous ; color light green, opaque ; apex decuticated, 



