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86 THE - CONCHOLOGISTS’ - EXCHANGE. 
. 
A Liogyro pupoideo, Gould, forma latiore, 
apertura haud soluta, umbilico majore, ultimo 
anpactu tumidiore et preecipue testa sinistrorsa 
discrepat. 
Several specimens of this very curious sinis- 
trorse shell were found in the Potomac, near 
Washington, D, C., by Mr. E. Lehnert, after 
whom I name it. Gould’s species was also 
found in the same station. : 
The New Caledonia shell, described as a 
Cyclostomoid (!) shell by Mr. Crosse, under 
the name of Heterocyclus Perroquini, 1s some- 
what allied to Valvata pupoidea, and the iden- 
tity of Heterocyclus and Liogyrus has been 
proposed, still it differs in having the labrum 
effuse and somewhat thickened (sometimes re- 
flected, as in another species which seems to 
have the same generic characters as Perroquini, 
although the aperture is not solute,—Valvata 
Petiti, Crosse). The author should have per- 
ceived the resemblance between the two shells. 
when describing Heterocyclus as a land shell !! 
ro.—Bithynia tentaculata, Lin. 
This European shell was sent to me several 
years since by Dr.W. Newcomb ; the specimens 
were collected at West Troy, and others have 
been found at Oswego, N. Y. ‘The presence 
of this well known species in the waters of N. 
America is doubtless the result of a recent im- 
portation. 
The surface of the specimens is much eroded. 
11.—Polygyrella polygyrella, Bland & Cooper. 
Helix polygyrella Bland & Cooper in Am. 
Naye., IN. Ye, evil, pe 305) pl. avenge. 13-15 
Binney (W. G.), in Bull. Mus. Comp. Zool., 
1886, p. 36, pl. vi. fig. 12-14. 
I have in my collection a variety (which 
may be called A/ontanensis) of that species, 
distinguished from the type in having a longer 
and more developed parietal tooth, more  tri- 
angular aperture, the basal margin of it being 
more thickened and horizontal, and also the 
ribs of the upper surface more distant and 
coarser. It has been figured by W. G. Binney, 
in the last said work, from a specimen col- 
lected by Mr. Hemphill in Deer Lodge Valley, 
Montana Territory. 
12.—Pupa corpulenta, Morse. 
Var, parietalis, var. nov. 
Testa dentibus duobus in pariete instructa. 
Ogden Canyon, Utah. 
BRIEF NOTES ON THE LAND AND 
FRESH-WATER SHELLS OF MER- 
CER CO., ILL. 
BY WILLIAM A. MARSH. 
FAMILY VALVATID. 
Genus Valvata, Muller. 
75,.—Valvata tricarinata, Say. 
Shell orbicular, tricarinate, light horn color, 
with three whorls or volutions, three revolving 
carinate prominent lines giving the shell a 
quadrate appearance. Spire convex, apex ob- 
tuse, umbilicus large, carinze placed—one on 
the upper edge of the whorl, one on the lower 
edge, and the third on the base beneath. 
This species is found rather abundantly from 
May to September, in all the small lakes of the 
Bay Island, and sometimes in our river sloughs, 
and seems to avoid swift running water. I find 
it usually associated with Somatogyrus subglobo- 
sus, Amnicola porata, Bythinella obtusa and 
Valvata bicarinata, 
76.—Valvata bicarinata, Lea, 
Shell orbicular, flattened above, bicarinate, 
thick, very light horn color, widely umbilicate, 
sutures impressed, spire depressed, whorls 3% 
to 4, convex; aperture rounded. ~ 
This shell is found here in the same localities 
as ¢ricarinata, and is often associated with it. 
It seems to be quite variable, in many respects 
resembling ¢vicavinata, but differs in being of 
a lighter color, wider umbilicus, very much 
larger in size, and, generally, the spire is much 
more depressed. 
Some specimens have a slight third carina. 
Mr. Lea says that the animal differs from that 
of ¢ricarinata. 
