PUPILLA, AMERICAN. 159 



be a race. Similar shells occur in numerous Colorado local- 

 ities, with intermediate sizes connecting with muscorum, so 

 that it is apparently to be regarded as an arid station or 

 hunger form rather than a true race; a view adopted from 

 Prof. Junius Henderson, who has studied it in Colorado. 

 The original description follows. 



"Shell small, very short, composed of 5 l / 3 whorls, the last 

 three forming the cylindric portion, those above forming a 

 very short, obtuse cone ; last whorl ascending a little, having 

 a stout buff crest behind the thin, well-expanded lip. There 

 is a small, short, parietal lamella but no other teeth. Length 

 2.5, diam. 1.5 mm." 



Types no. 104005 A. N. S. P. from Duran, N. M. Also 

 found in the following localities, all in Colorado : Trinidad, 

 Pilsbry and Ferriss, 1906; Magnolia, Boulder Co., 8000 ft., 

 D. McAndrews; Estes Park, E. H. Ashmun ; Black Lake 

 Creek, T. D. A. Cockerell; near Golden, 7000 ft., E. E. Hand. 



The length varies from 2.25 to 2.75 mm. in the lot taken 

 at Duran. 



3. PUPILLA BLANDI Morse. PI. 19, figs. 1 to 5. 



Shell rirnate, ovate-cylindrical, delicately striated, opaque, 

 light brown. Apex obtuse, nucleus with microscopic granu- 

 lations. Suture well denned. Whorls 6, subconvex, the last 

 ascending at the aperture, rapidly expanding, with an ex- 

 ternal whitish callus, between which and the peristome there 

 is a deep constriction. Aperture small, nearly circular, with 

 three obtuse teeth of about equal size : one on the parietal 

 margin, one on the columellar margin, and the third far 

 within and at the base of aperture; peristome subreflected, 

 the margins joined by a thin callus. Length .13 inch, breadth 

 .06 inch [=3.25 x 1.5 mm.] (Morse). 



Rocky Mountain region, from Montana (and Bed Deer, 

 Alberta) to New Mexico; west to Nevada; eastward in the 

 semiarid region (mainly as a fossil, or in river drift) to 

 McLean Co., North Dakota (at Ft. Berthold, type loc.), 

 Brule Co., South Dakota, Phillips Co., Kansas, Comal Co., 

 Texas. 



