THE NAUTILUS. 



VOL. XII. SEPTEMBER, 1898. No. 5. 



BIFIDARIA ASHMUNI. A NEW SPECIES OF PUPIDJE. 



BY DR. V. STERKI. 



Shell cylindro-conical, with the apex rather acute, base perforated- 

 rim ate ; whorls five, convex, with a rather deep suture, regularly 

 increasing, the last somewhat proti acted, with a crest remote from 

 the aperture and forming a projecting angle at the base, at last 

 ascending; aperture strongly lateral, rounded subtriangular, equal- 

 ling one-third the altitude of the shell, highest near its columellar 

 side, with a sinus above on the palatal side; margin continuous, 

 strongly everted, broadest so below, without a lip thickening; 

 parietal lamella very large, strongly curved, nearer the periphery 

 at its inner end ; angular lamella large, at its inner end united with 

 the side of the parietal, at the outer with the palatal margin, thus 

 closing the sinus above; columellar lamella large, spiral, ascending 

 to the body whorl between the parietal and columella ; basal lamella 

 and inferior palatal fold deep in the throat, the former radial, the 

 latter above it, oblique; superior palatal short, tooth-like, rather 

 remote from the margin ; surface shining, with slight, irregular 

 stria? and microscopically rugulose, as is also the nucleus; shell 

 horn colored, transparent ; lamella? and folds whitish ; alt. 2'0, diam. 

 1-1 mill. 



Habitat: Arizona and New Mexico. 



The soft parts could not be examined. In one living specimen, 

 the foot and head were almost colorless, the mantle was slate- 

 colored. 



