THE NAUTILUS. 53 



Distribution: Southern, especially southwestern; it appears to be 

 the prevalent form in Kansas, Arkansas, Oklahoma, and thus repre- 

 sents a geographical variety. 



B. a. iimilis, n. var. Averaging somewhat smaller; more cylin- 

 drical, often more or less conical; whorls less convex; surface striae 

 slighter; shell generally more milky-whitish, as noticed especially 

 when a number of each, armifera and similis, are placed side by side; 

 peristome never continuous, somewhat less everted; the columellar 

 lam. is slighter, generally more protracted downward, the lower 

 palatal is shorter, sometimes quite short; the spur of the parietal is 

 larger. 



Distribution; Northern New York to Iowa, Minnesota, Ontario. 



£. a. affinis, n. var. Somewhat small and slight; near similis, but 

 less cylindrical, rather somewhat oblong; whorls 6-6^, somewhat 

 more convex than in similis., the last rounded at the base and little 

 flattened over the palate, with none or a slight scar over the lower 

 palatal plica; aperture somewhat rounded, peristome never continu- 

 ous; parieto-angular lam. well connected with the peristome, spur of 

 the parietal larger than in typical armifera; columellar nearly axial, 

 a broad lamella, reaching down to the base, with distinct lines of 

 growth, visible from the outside through the (fresh) shell below the 

 umbilicus, as in B. contracta ; inferior columellar wanting or smalll 

 lower palatal quite short, or even a transverse, short, abrupt lamella. 



Alt. 3.5-4, diam. 2.2-3 mm. 



Distribution: Northern Ohio, Michigan, Indiana to Minnesota 

 and Kansas; seems rather scarce in the first-named States, common 

 in Kansas. Found, e. g., on sandy dunes on Lake Erie in Ohio. 



It is notable and significant that both the columellar and the lower 

 palatal in this form are of the same shape as in B. contracta, while 

 in typical armifera they are quite different, yet the latter shows a 

 tendency to having the peristome continuous, while in affinis its ends 

 are always apart. 



B. a. abbreviata, n. var. Averaging rather small, slight, some- 

 what fusiform to ovate or cylindro-conical; apex low, conical or 

 rounded; whorls only 5^-6 (rarely 6^), little convex, with the penul- 

 timate comparatively broader than in the other forms, the last 

 rounded at the base, slightly flattened over the palate; color some- 

 what milky-whitish; surface with a dullish gloss, striae fine and slight; 

 aperture somewhat small; peristome moderately everted, its ends (in 



