162 HELICID^. 



DESCRIPTION. 



Animal corpulent, gradually tapering. Color pale 

 yellowish green ; surface with rather sparse, feebly 

 developed, elliptical granules, not seeming to have any 

 regular arrangement. Margin of disk rather broad, 

 granulated, but regularly marked with radiating fur- 

 rows. 



Shell obtusely convex ; epidermis yellowish and 

 brownish horn-color more or less intermixed ; suture 

 distinct ; whorls five and a half, with minute, impressed, 

 longitudinal striae, which can scarcely be traced by the 

 eye, and coarse, oblique wrinkles and striaj ; body-whorl 

 large, voluminous, rough, and corrugated ; aperture 

 rather large, somewhat rounded ; Up white, fully re- 

 flected at the base, and but partially so towards its 

 superior part, thickened and a little projecting internally 

 in the base of the aperture ; umbilicus open, deep, a 

 little contracted by the reflection of the lip ; base con- 

 vex and turgid. 



Greatest transverse diameter one inch and three- 

 eighths. 



Geographical Distribution. Inhabits the neigh- 

 borhood of the Wahlamat, near its junction with Colum- 

 bia River, whence it was brought by Mr. Nuttall, by 

 Dr. Townsend, and by the U. S. Exploring Expedition. 



Remarks. This shell is peculiar by the irregular 



