30 BOOK OF SPECIES. 
P. umBILICATA. Minute, cylindrical, obtuse, 
sub-pellucid; aperture with one tooth ; lip with 
a white reflected margin; umbilicus open. B. 
Tt. 76. 
P. muscorum. Principally differs from the 
last by its tooth not adjoining the margin, but 
being placed further in the interior of the shell ; 
it also has a prominent white rib at the back of 
the outer lip. B. T. 79. 
P. rraqiuis. Turreted, pellucid, with the 
whorls reversed, and the aperture toothless; yel- 
lowish brown. i. B. T. 70. 
P. pyemMeA. Minute, fulvous horn-colour, 
cylindraceous, obtuse ; whorls five ; aperture four- 
toothed; peristome reflected; umbilicus very open. 
oe. a. 
P. vertTIGO. Minute, reversed, horn-coloured ; 
five whorls ; aperture with six plaits; peristome 
sub-reflected, sinuated; umbilicus nearly closed. 
im,” -C. 86. 
P. ANTVERTIGO. Oval, ventricose; aperture 
with eight unequal teeth, three of which are su- 
perior, and between the lips of the peristome ; 
deep chestnut, and margin of aperture whitish ; 
minute. B. T. 85. 
P. Goopauu1. Oblong or conical, cylindri- 
cal, brown horn-colour, semi-transparent, quite 
smooth and glossy, except close to the sutures; 
