474 PROCEEDINGS OF THE ACADEMY OF [1898. 



subcylindrical or barrel-shaped, those above rapidly tapering, form- 

 ing a rather short, conic spire. Whorls 6? or 7, nearly flat, the last 

 with a more or less distinct basal keel on its latter half, and having 

 a small flattened tract within the keel behind the basal lip. Aper- 

 ture slightly oblique, shortly, irregularly ovate, obstructed by three 

 principal lamellre and one or two smaller denticles or teeth ; one 

 lamella well within on the parietal wall, bifid at its outer end ; 

 one very obliquely entering lamella on the columella; and a third 

 lamella within the outer lip near its middle. Besides these there 

 is a denticle or very small lamella on the basal lip near the foot of 

 the columella, and another within the outer lip above the median 

 lamella. 



Alt. 19, diam. 9, length of aperture 8J mm. 



Alt. 20, diam. 9, length of aperture 85 mm. 



Sierra Ventana, Argentine Republic. 



This species does not seem to be closely allied to any of the numer- 

 ous Argentine forms described by Doering, a part of which have not 

 yet been figured. Only one of the specimens shows the small den- 

 ticle above the lamella on the outer lip. 



