THE NATURAL HISTORY SURVEY. 141 
“Shell; Helicoid, varying from globose or depressed-glo- 
bose to lens-shaped or planorboid, the periphery carinated or 
rounded; umbilicus either open or closed. Surface striated or 
hirsute; corneus, yellow or brown, generally unicolored, but 
sometimes with many bands, ¢he most constant being supra-periph- 
eral the others when present being wholly indefinite in number 
and position. Lip well reflexed; aperture typically obstructed by 
the teeth,—one parietal, two upon the lip; but any or all teeth often 
wanting.” 
“Animal: (Fig. 14). Externally as in Helix, the mantle 
subcentral, foot rather long and narrow, not distinctly tripartite 
below, and without longitudinal grooves above the lateral mar- 
gins, although a sort of foot-margin is produced by the tessel- 
lated granulation of the edge. Surface rather coarsely irregu- 
Animal of PoLyGyra. (After Binney.) 
larly granulated, the granulation finer posteriorly; back with 
a pair of indistinct grooves extending from mantle to facial 
area; szdes of foot, and sides and top of tail without any atstinct ob- 
lique or longitudinal lines, irregularly granulated, tail rounded 
above, obtuse behind. Mantle edges reflexed to correspond 
with the lip of the shell, its edge even; shell lappets none; 
body-lappets small, the right one long, giving off a short as- 
cending branch behind the lung-pore; left lappet very small, 
short.” 
“Genitalia: Completely lacking accessory organs ; retractor and 
vas deferens inserted at the apex of the penis. Spermatheca 
oval or oblong, situated upon a short simple duct. The penis is 
divided internally into two parts: (1) a lower, invertible por- 
tion, the inner surface of which shows few or many longitudi- 
nal folds, which are smooth and may be either weak or strong 
and acute; and (2) an upper portion the cavity of which has 
finely corrugated walls and is partly filled by one or two fleshy 
pillars adherent along the sides.’’* ( Fig. 15.) 
*Pilsbry, Guide to Helices, pp. 69 and 70; see also Proc. Phil. Acad. 1892, p. 400. 
