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THE: CONCHOLOGISTS! EXCHANGE: 
they have any resemblance to Azc. prerosa, as 
he suggests in his observation. Ata glance I 
would take them for some of the “heavy pu- 
peeform or cylindrical species’? of Goniobasis. 
Some of them compare well with Gor. /epida 
in general outline, and a few resemble fig. 576, 
on page 299 of ‘Tryon’s ‘‘ Strepomatide.” 
Found most plentifully where there was con- 
siderable current. 
Subgenus Pleurocera, Rafinesque. 
P. alveare, Conrad. 
Shell with a row of small tubercles on the 
last whorl, four or five striz on the base, 
wanting on some, first few whorls plicate, to be 
seen only on young specimens, as all mature 
ones are decollate. Habitat, Saline river. 
Common, found in swift water on rocks. 
P. undulatum, Say. 
Shell large with an impressed band, tubercu- 
late on the angle of last whorl; on some the 
tubercles are hardly discernible. Habitat, 
Wabash river and ponds. Ali specimens col- 
lected were in still water, on sand or mud bot- 
tom, 
P. moniliferum, Lea. 
Shell striate on the 
banded. 
the same. 
base, banded or not 
Close to the last species, and may be 
Found in the same situation. 
P. canaliculaium, day. 
Shell with a deep groove on the last whorl ; 
difters from the two last species by not having | 
tubercles, and not so strongly angulate on the 
periphery. One specimen collected has two 
well-defined grooves on the last whorl, one of 
which is on the next two preceding ones. 
Habitat, Wabash river. 
P. troostii, Lea. 
Shell, carinate on the body-whorl; a few 
faint striz on the base. A few are banded, 
and some have a slight groove on the last 
whorl. Habitat, Litthe Wabash and Saline 
rivers. It is common in the latter stream, and 
inhabits swift water. 
P. subulare, Lea. 
Shell acutely elevated, striate, carinate. 
rather thin ; whorls ten to twelve. Common in 
the northern part of the State. Specimens re- 
ceived from Mr. W. A. Marsh, of Mercer 
county, are more elongate than those from 
other localities. 
P. lewtsti, Lea. 
Shell striate on the base, carinate, one or more 
grooves on the last two or three whorls. It is 
a larger species than 2. sedu/are,and the spire 
is not as acute. Received from Mr. J. Wolf. 
Habitat, Spoon river. 
P. elevatum, Say 
Shell carinate on the frst few whorls, last 
one angulate, and differs from /. éewésez in size 
and not having the grooves or sulcations. Hab- 
itat, northern part of the State. 
A form found in the Kaskaskia river has the 
whorls flat, and they do not increase in size as 
rapidly as in the northern specimens. Often 
when the first few whorls are gone the shell 
has a cylindrical appearance, white within the 
aperture, and sometimes has two bands. I 
have sent this form out as P. elongatim, Lea. 
P. neglectim, Anth. 
Shell white within epidermis yellowish, car- 
inate on the upper whorls, base striate, three 
banded; a few being without bands. Habitat, 
Little Muddy Creek, Washington Co, At one 
place where the current is rapid and running 
over fine gravel and mud, and shaded by for- 
est trees, they were found in abundance. 
Genus Goniobasis, Lea. 
G. costifera, Hald. 
Shell plicate on the upper whorls, with two 
or three revolving lines; color, brown or red- 
dish brown; whorls, 7 or 8. This species is 
common in the creeks of Hardin Co., and dif- 
fers somewhat in color and size in the different 
streams, but the specimens are very much alike 
in form and markings. 
There are other species of Govzobasis found 
in the State, and may be other species of Plew- 
vocera, but I have seen none of them. Per- 
haps some of the readers of “THE CONCHOLO- 
cists’ EXCHANGE can give some information 
of others. 
