THE - CONCHOLOGISTS’ - EXCHANGE. 
gt 
cus narrow, aperture semicireular; labrum ap- 
pressed within; sutures impressed. 
T his fine little shell inhabits the Myers’ Slough, 
below the Bogus Island, very near the river. 
In 1822 I found it in great abundance clinging 
to the moss which coyered the whole bottom 
of the slough, which is what is known as a 
spring slough, being fed by numerous springs, 
the water being very clear and cold. It isa 
very small species, not over one-half the size 
of Somatogyrius subglobosus. As found, here it 
is nearly typical. I have been informed that 
of Davenport, Iowa, furnished Mr. Tryon with 
his type specimens. I have never found the 
little shell in any other locality in our county, 
and I am inclined to believe that it 1s found 
only in localities where the water is very clear 
and cold. 
Genus Amnicola, Gould and Halde- 
man. 
81.—Amnicola porata, Say. 
Shell obtusely conic, or subglobose, volutions 
four, rather convex, very slightly wrinkled. 
Spire obtuse, labrum and labium equally 
rounded, meeting above in a sub-acute angle, 
the upper edge of the latter appressed to the 
preceding whirl. Umbilicus distinct, This 
species is probably common in all the sloughs 
of the Mississippi River, and in the Bay Island 
lakes. It is one of those species that is fond of 
muddy situations often associated with 4. osa 
and Som. sebglobosus. The difference between 
porata and fimosa is so slight that they are 
difficult to separate. Both of these species prob- 
ably range from Maine to Colorado and Texas. 
Porata seems to differ from 4. Amosa in being 
larger and more globuse and has a more dis- 
tinct umbilicus. It is not found here as numer- 
ous as Ze705a. 
82.—Amunicola limosa, Say. 
Shell conic, sub-umbilicate, dark horn col- 
ored, epidermis obsoletely wrinkled, aperture 
ovate-orbicular, suture impressed. This shell is 
probably much more common than 4. forata, 
and is usually found in our river sloughs, often 
associated with fovata. It seems to prefer mud- 
dy localities. J have found it in considerable 
numbers along the margins of Sturgeon Bay, 
but not later than the latter part of August. I 
have also found it sparingly several miles up 
the Bay in the Myers Slough associated with 
Som. depressus. 
83.—Amnicola Cincinnatiensis, Anthony. 
Shell ventricose, sub-umbilicate, greenish 
horn color, whirls four and one-half to five, 
very smooth, spire entire at the apex. 
Sutures deeply impressed, aperture dilated,orbi- 
cular. ‘This, our largest Aszicola, is perhaps 
rare here, as only about a dozen specimens have 
been found, and these in but one locality, at the 
: : oo Renae | junction of the Lakey and Hanneman Sloughs. 
my friend, the late Professor David S. Sheldon, J ¥ = 
In the tertiary clay beds of our county are 
found fossz/, what I suppose to be two species 
of Ammnicola, probably Cincinnatiensis and 
porate. 
S4.—Amnicola parva, Vea. 
Shell obtusely conical, rather thin, yellowish, 
smooth, umbilicated, Spire short, suture im- 
| pressed, whirls four, inflated, aperture large, 
nearly round. 
This very small species! did not suppose 
would be found in our county, but quite re- 
cently, on making a critical examination of a 
lot of amnicola and the Somatogyrus depressus 
from Myers Slough, Bay Island, I found a 
very few of this shell. Future explorations 
may reveal the fact that it is quite common in 
the locality mentioned. It is a little difficult 
to distinguish from di, orbicula‘a. and even 
the young of Som. depressus without the aid of 
a good glass. It is probably common in Win- 
nebago County. My friend, Mr. J. B. Upson, of 
Rockford, sent me several hundred of this very 
interesting little species. 
SUB-FAMILY POMATIOPSIN, STIMP- 
SON. 
Genus Pomatiopsis, Tryon. 
85.—Pomatiopsis lapidaria, Say. 
Shell turreted, sub-umbilicate, with from five 
to seven volutions, dark horn color, whorls 
rounded, suture impressed, aperture longitudi- 
nally ovate-orbicular, operculated. 
This very interesting little univalve used to 
be quite common along the margin of all our 
small sloughs, adhering to leaves, sticks of 
wood, and stones; also along Edward’s and 
Pope Creeks, but at present it is rarely found, 
and no doubt in a few years will become en- 
