THE NATURAL HISTORY SURVEY. 23 



Length, 2.00; diameter, 1.15; aperture length, 0.85 mill. (11996.) 



Animal: Of the usual form; color grayish white under- 

 neath and blackish above and on eye-peduncles. The foot is 

 quite long and rather wide; eye-peduncles rather long and 

 somewhat tapering; tentacles rather long, blunt, cylindrical. 



Jaw : Similar to that of V. milum, slightly arcuate, width 

 uniform, ends broadly rounded; concave margin notched and 

 anterior surface striated longitudinally. 



Radula formula: ^-T+l+i+f+^-y (10 I 10); central 

 tooth long and narrow, the tricuspid reflection very small; 

 lateral teeth very wide, reinforced at the lower outer corner by a 

 very small appendage to the base of attachment; marginals 

 as in the other species. There are over 60 rows of teeth. 



Genitalia: Unknown. 



Distribution: "Ontario and Quebec, Canada, to Minnesota, 

 south to Georgia and Texas; Lincoln Co., Nevada; Laggau, 

 B. C." (Pilsbry.) Manitoba. (Hanham.) 



Geological distribution: Pleistocene. 



Habitat: Found about dead leaves under sticks, stones 

 and rubbish, and about the foot of trees in low, moist locali- 

 ties. 



Remarks: This species is distinguished from all our Pupae 

 by the small size and number of the teeth in the aperture, and 

 also by the teeth being simple, especially the parietal tooth, 

 which is small and narrow. It seems to be quite common and 

 loves to congregate under leaves in little colonies. It is found 

 in both the northern and western regions. One of the best 

 times to collect this species is after a rain, when they will be 

 found crawling over fallen trees, leaves and old debris. 



95. Bifidaria curvidens Gould. Text figure 69. 



Pupa curvidens GOULD, Journ. Phil. Acad., Vol. II, p. 476, 1822. 

 Pupa curvidens floridana DALL, Proc. U. S. Nat. Mus., p. 251, pi. xvii, 



fig. 11, 1885. (Variety.) 

 Pupa curvidens gracilis STERKI, L. and F. W. Moll., New Phil., Ohio, 



1894. (Variety.) 



Shell: In general form like that of pentodon but smaller; 

 aperture more rounded than in pentodon and six-dentate, as 

 follows: a single large, curved tooth on the parietal wall, which 

 descends for a considerable distance into the aperture; a large 

 columellar tooth, conical, placed about the middle of the col- 

 umella; a third very small, conical tubercle placed at the left- 

 hand turn of the peristome; a fourth, small, conical tubercle 



