HELIX. 107 



DESCRIPTION. 



Animal not observed, 



Shell very globose, transparent, brittle, thin, shining, 

 reddish ; spire very short, conic ; whorls four, convex, 

 lightly wrinkled, rapidly increasing, the last very large and 

 ventricose ; suture moderate ; aperture circular, equally 

 high and broad, within bluish and slightly thickened by a 

 very thin white callus ; perist. simple, sharp, thin, at its 

 junction with the body whorl, violet-colored and reflected, 

 so as to cover a portion of the small and deep umbilicus ; 

 the parietal wall of the aperture is covered with a light 

 violet-colored callus. 



Greater diameter, 26 ; lesser, 20 ; height, 13 millimetres. 



Geographical Distribution. Found by Mrs. Say on the 

 banks of the Wabash, Indiana, and in Illinois by Kenni- 

 cott. Occurs also in Alabama (Showalter), and Texas, 

 (Moore). 



Remarks. Belongs to the same group as H. fuliginosa 

 Binney but readily distinguished from that and all de- 

 scribed species by its transparent, globular shell, ventricose 

 body whorl, and circular aperture. At the localities where 

 it was found it seems to take the place of H. fuliginosa , 

 as that species does not occur with it. 



The specimen figured was found by Mrs. Say, as stated 

 above. From Texas the specimens are much heavier. 



HELIX CADUCA PFEIFFER, 



This species was originally described from Mexico, but 

 is catalogued by Roemer (Texas, 455) as found at New 

 Washington. The species is nearly allied, if not identi- 

 cal, with lucubrata Say, as already observed in the remarks 

 on H. fuliginosa. Pfeiflfer's description is given below. 



T. umbilicata, depressa, fragilis, breviter striatula, albida, epidemic 

 f ulvo-cornea induta ; spira parum elevata, vertice subtili ; anfr. 5 con- 

 vexiusculi, ultimus inulto latior, basi subplanulatus, circa umbilicum 



