159] FAUNA OF BIG VERMILION RIVER—BAKER ol 
wide and not exceeding six inches in depth. The bottom was of mud and 
fine sand. The largest specimen measures 7 mm. in length. This spe- 
cies was not collected from streams flowing into the Big Vermilion River. 
50. Amnicola limosa (Say). 
This common Amnicola occurred at three stations, only two of these 
yielding living specimens. At the station above the iron bridge north of 
Sidney, the shells were secured by sweeping the vegetation bordering the 
shore with the Walker dredge. The /imosa from the Salt Fork are rather 
corpulent but are not as globular as the variety known as porata (Say). It 
is noteworthy that this species (and in fact the genus) should be found only 
in a stretch of the stream three miles in length, from 16 to 19 miles below 
Urbana. None were seen below the dam. Individuals were rare and 
difficult to find. Near the cement bridge east of Sidney, dead shells 
occurred among water plants (Nymphaea advena) but no living specimens 
could be found. Limosa was not collected at the stations in the San- 
gamon River. 
51. Amnicola (Cincinnatia) cincinnatiensis (Anthony). 
This Amnicola occurred rarely, but living, at but two stations in the 
Salt Fork, 16 and 17 miles below Urbana. The largest and only adult 
individual collected measures 6 mm. in length. Several half-grown shells 
were found. About two years ago Mr. James Zetek found cincinnatiensis 
near St. Joseph. A careful search of this region, both in the Salt Fork 
and in the small streams flowing into Salt Fork, failed to produce a single 
specimen of this species. During the intervening ten years the species 
appears to have died out, either from the effect of sewage pollution or 
from some other unknown cause. 
FAMILY VIVIPARIDAE 
52. Campeloma rufum (Haldeman). 
The Campelomas of the Big Vermilion all appear to be referable to 
Haldeman’s rufum. The shell is more or less pinkish, especially on 
the spire. One specimen from the iron bridge north of Sidney resembles 
Haldeman’s figure 1 on plate 3 of the Monograph, which is the type 
of rufum. Specimens from Homer Park, below the dam, are strongly 
suggestive of integrum (Say), many of the individual shells being like 
Binney’s figure 96 which represents Say’s integrum. With these are 
short-spired shells recalling the obesum of Lewis as figured by Binney 
(figure 95). These are not quite like the figures of Lewis (1875, pl. 23, 
figs. 4-5) which are rather broader. Variation in rufum seems to parallel 
that of integrum in the length of the spire. Typical integrum has a white 
aperture and a bright green shell devoid of the peculiar pink tint of rufum. 
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