THE CONCHOLOGISTS? - EXCHANGE: 65 
BRIEF NOTES ON THE LAND AND 
FRESH-WATER SHELLS OF MER- 
CER CO., ILL. 
BY WILLIAM A. MARSH. 
(Continued. ) 
FAMILY VIVIPARID. 
This family is represented in Mercer County 
by three genera, viz: Vivipara, Lamarck, three 
species; Campeloma, Rafinesque, three species ; 
and Lioplax, Troschel, one species. 
GENUS VIVIPARA, LAMARCK. 
68.— Vivipara intertexta, Say. 
Shell sub-globose, yellowish-green, olivaceous 
or dark brown, with many minute, obsolete 
revolving lines; spire depressed, conic, obtuse, 
truncated ; whorls five; suture deeply indented ; 
umbilicus only partially closed by the lateral ex- 
tension of the columella; sometimes ornamented 
with two or three plain bands, although usually 
without band. ‘This fine shell is rather common 
in all the sloughs near the river, and in the small 
lakes of the Bay Island. It was the opinion of some 
of our early conchologists that this species was 
only found in deep water, but my experience | 
teaches me differently. I find very fine live 
specimens in very shallow water, especially 
during certain seasons of the year, when this 
species is most active. In the Myers Slough I 
have collected many fine specimens in clear | 
It is found | 
water not three inches in depth. 
rather rarely in the river proper, but I occa- 
sionally find it under flat stones, associated 
with V. subpurpurea. here are two varieties 
here; the dark brown, and the light colored 
having a yellowish-green epidermis and usually 
ornamented with pale, rather obsolete bands. 
The last named variety is smaller in size. 
Often during sudden rises in the waters many 
specimens of this shell may be found clinging 
to the underside of pieces of bark, chips, or 
small sticks of wood floating near the margins 
of the sloughs and lakes. 
69.—Vivipara subpurpurea, Say. 
Shell oblong, sub-globular, oval, thick and 
solid when adult; whorls five; sometimes 
wrinkled, often smooth and shining; spire 
slightly elongated ; suture impressed; epidermis 
variable, olivaceous, pale horn, yellowish-green, 
and sometimes with a purple tinge, often orna- 
mented with from three to five pale purple 
bands on the body whorl; aperture widest in 
the middle; interior of shell varying from pearly 
white to reddish purple; umbilicus in some 
specimens entirely closed, and in others only 
partially closed. 
The young and halfgrown of this species 
differ so much from the adult that it is very 
difficult to describe. As found here in the 
river it is variable, and during different stages 
of growth might easily be mistaken for more 
than one species. It is rather rare here, only 
being found in the Mississippiriver. The time to 
collect it is when the water is very low, when 
it is generally found attached to the under sur- 
face of flat rocks, and sometimes under logs that 
have lain a long time under water. I have 
never found it upon muddy bottoms, and it 
must be sought for where the current is usually 
rather strong, with plenty of sand, gravel and 
rocks at the bottom. Near the mouth of Ed- 
wards Creek, in the Mississippi, is the only lo- 
cality in which I have found this shell in any 
numbers. Itis likely that J. sebperpurea and 
V. intertexta are found the whole length of the 
Mississippi from Minnesota to Louisiana. 
70.—Vivipara contectoides, WW. G. Binney. 
Shell elongate-ovate, rather thin, smooth, 
shining, growth lines delicate, greenish horn 
color to light brown, with longitudinal dark , 
lines marking the former peristome and orna- 
mented with four well defined brown bands re- 
volving around the body-whorls, only partially 
umbilicated ; apex, usually entire ; whorls, five, 
bulging, increasing very, rapidly in length, last 
whorl ventricose. Aperture sub-circular,oblique, 
white within, showing the bands plainly, which 
do not reach the edge of the aperture; peris- 
tome dark, thin, sometimes shining, somewhat 
reflected at the umbilicus. Found only in the 
Cowan and Bention Sloughs, below Neithsburg. 
This, our largest /7z¢para, often attains a large 
size. Remarkably fine specimens of this shell 
