LYMNZIDZ OF NORTH AMERICA. 401 
some specimens and coarser in others, crossed by very indistinct 
spiral impressed lines; in old specimens the shell becomes very rough 
and eaten away by the excess of carbon dioxide in the water; whorls 
3%4 in perfect specimens, but generally only 2 to 21% remain intact, 
the tip of the spire being decollated; the whorls are rather flat sided 
on the spire, the body whorl alone being ventricose and sometimes 
roundly sloping above the periphery; apex light horn color, small, 
rounded ; spire very short, broadly conic, generally decollated ; sutures 
tightly appressed, in some specimens distinctly impressed; aperture 
large, ovate, occupying two-thirds the length of the shell, in old speci- 
mens distinctly campanulate; peristome thin, acute; the outer lip is 
inclined to thicken within the aperture and a transverse varix edged 
with reddish brown is sometimes formed; inner lip reflected over the 
parietal wall and umbilicus, tightly closing the latter; the axis is 
slightly twisted and there is a well marked fold. 
Length. Breadth. 
15.00 12.50 mill. (Mighels .6 by .5 inch.) 
15.00 1050>> = Tryon. 
Aperture length. Breadth. 
12.00 8.00 9.00 5.50 mill. Walker, received from Mi- 
ghels. 
12.25 8.00 9.00 5.50 “ Walker, received from Mi- 
ghels. 
11.25 05 8.00 5.00 “ Walker, received from Mi- 
ghels. 
9.75 7.00 7.00 4.50 “ Walker, received from Mi- 
ghels. 
11.00 7.50 8.00 5.00 “ Walker (J. G. Anthony). 
1G larg 8.00 8.25 500) > Phil. Acad. Sci. 
12.00 8.50 8.50 AVS On anes Smith. Inst. 
14.00 11.50 9.25 000 = : 
17.00 1 LE 12.50 6:50) Ss) ‘Bost SooeNe Ee 
15.25 11.00 11.50 G25) oe oF - “s 
Tyres: Destroyed in Portland fire of 1866. Specimens received 
from Mighels are in the collection of the Academy of Natural Sci- 
ences, Philadelphia, No. 58703; in the Boston Society of Natural 
History, No. 24192; the Chicago Academy of Sciences, No. 23811 and 
in the collection of Mr. Bryant Walker. 
Type Locarity: Lake Winnecook, Unity, Waldo Co., Maine. 
ANIMAL: “Dingy mouse-color, with a slight tinge of purple; 
covered with numerous microscopic, elongated white spots on every 
visible part of the surface, including the mouth and tentacula; foot 
of a chocolate color, rather broad, length rather greater than the 
aperture.” (Mighels). 
