so) 
wt Tan” 
ont st. Sp: 
THE NATURAL HISTORY SURVEY. 229 
otherwise similar to the rest of the family. The foot is very 
long and narrow, almost, or quite, equaling the shell in length. 
Jaw: Of the usual form, wide and slightly bent. The 
ends are blunt. Surface without ribs but vertically striated. 
Radwa formula: 38;+4+4+4+ 33, (I5—I—I5); some 
membranes seem to have the following formula: ,8;+§+1+ 
$+ 78,(14—1—14). The centrals are narrow, the laterals very 
wide, while the marginals are, as usual, low and wide with one 
large inner cusp, and several (2-6) small outer cusps, which are 
rather blunt. 
Genitaha: Unknown. 
Distribution: ‘‘Province of Ontario, Canada to Florida and 
west to Minnesota, Texas and Arizona.” (Pilsbry.) 
Geological distribution: Pleistocene; Loess. 
Habitat: Found generally in open pastures or on the edge 
of woods, under stones, on blades of grass and about old wood. 
Seldom found in woods. | 
Remarks: A species at once distinguished by its turreted, 
fusiform shell’ and unarmed aperture. It is a rather common 
mollusk and is widely distributed in the northern and western 
regions. 
Genus BIFIDARIA Sterki.* 
Bifidaria STERKI, The Nautilus, Vol. VII, p. 99, 1892. 
“Shell; Cylindrical, turriculated, conical or oval; color 
varying from whitish to chestnut; surface smooth and polished 
or finely striate; sometimes lightly ribbed; aperture dentate, 
the parietal tooth being generally large and bifid or bifurcate; 
two (superior and inferior) palatal plice always present, gen- 
erally deep-seated; a tooth is generally found at the base; ad- 
ditional denticles may sometimes be found, one on the parie- 
tal wall, between the parietal tooth and the columella, one 
above the upper palatal and one between the two palatals; 
columella somewhat complex.’ (Sterki.) 
Section PRIVATULA Sterki. 
“Shell cylindric; lamella few or none.’”’ (Sterki.) 
89. Bifidaria corticaria Say, pl. xxx, fig. 10. 
Odostomia corticaria SAY, Nich. Encycl., Vol. IV, pl. iv, fig. 5, 1817. 
First edition. 
Pupa corticaria Say, Nich. Encycl., Vol. 1V, pl. iv, fig.5, 1819. Third 
edition. 
*See The Nautilus, Vol. V1, p 2, 1892, fora list of the North American Pupide. 
