242 THE CHICAGO ACADEMY OF SCIENCES. 



Length, 1.40; diameter, 0.90; aperture long, 0.30 mill. (11997.) 

 1.30; " 0.80; " " 0.25 " (11997.) 



Animal: Similar in form to the other species of Vertigo ; 

 color dirty white, darker on the upper surface; foot very broad, 

 posterior of the center, from whence it tapers rapidly to a 

 point; the foot is thick and fleshy and well able to support the 

 light shell; eye-peduncles of medium length, somewhat en- 

 larged at the tips, where the eyes are placed. 



Jaw: Very slightly arcuate, the ends a trifle rounded; 

 concave margin notched and anterior surface lightly striated. 

 The jaw is of equal width throughout its length (Fig. 71). 



Fig. 71. 

 Jaw of VERTIGO MILIUM Gould. (Original.) 



Radula formula: ^-T+l+i+l+^-y * ~ * ' l )> teeth as 

 in the other members of the genus, and resembling closely those 

 of B. contracta but somewhat wider. There are four perfect 

 laterals and the first marginal similar but with a second outer 

 cusp; from this point the marginals become wider, the inner 

 cusp remains always the larger, and the outer cusp develops 

 from five to seven small cusps or denticles. 



Genitalia: Unknown. 



Distribution: Maine to Minnesota, Ontario and Quebec, 

 Canada, to Florida and Texas. (Pilsbry.) 



Geological distribution: Pleistocene; Loess. 



Habitat: Gregarious. Found plentifully under leaves, 

 stones and sticks, in moist situations. 



Remarks: This is the smallest of our Pupae and is a very 

 beautiful species, the peculiar gular lamina, dark chestnut 

 color and globose-fusiform shape serving to distinguish it at a 

 glance. There are sometimes several small accessory tubercles 

 developed, but these do not affect its general specific charac- 

 ter. It is confined, so far as known, to the northern and west- 

 ern regions. 



SUBGENUS VERTIGO Drap. (Typical.) 



97. Vertigo ovata Say, pi. xxx, fig. 13. 



Vertigo ovata SAY, Journ. Phil. Acad., Vol. II, p. 375, 1822. 



Pupa modes fa SAY, Long's Exped., Vol. II, p. 25, pi. xv, fig. 5, 1824. 



Pupa ovulum PFEIFFER, Olim. Symboloe, Vol. I, p. 46. 



Zonites upsoni CALKINS, Valley Nat., Vol. II, No. 4, p. 53, fig. 1880. 



