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PAPERS ON ZOOLOGY 155 
1 Lampsilis ventricosa, 3 Lasmigona complanata and 1 Ano- 
donta grandis. Such heaps were plentiful and show only too 
well how severe are the inroads made by Fiber zibethicus in the 
clam world, notwithstanding the fact that his chief food is 
vegetable matter. The muskrat takes the clams during Autumn, 
Winter and early Spring, when the corn and grain fields offer 
him no food. . 
Vermilion County. The Vermilion River, with its North and 
Middle Forks, rises in Ford and Iroquois Counties and drains 
into the Wabash River. The Middle Fork at Hillery contains 
much drifting sand. The depth of water varies in all these 
branches according to the season. Too few collections were 
made of the Unionidae to warrant making definite conclusions, 
however, it is evident that in several respects the fauna of this 
drainage system is quite different from that of the Sangamon. 
Quadrula cylindrica and Obovaria circulars collected here are 
typical of the Wabash Drainage. 
The hillsides at Hillery are very favorable for helices; Poly- 
gyra elevata, P. albolabris and P. thyroides are the most 
abundant. Unfortunately man with his fire, destroyed an ex- 
tensive area of this splendid Polygyra habitat; the calcined 
shells are strewn all over the place. Near the stream the low- 
land mesophytic plant association merges into a typical hydro- 
phytic type with Lymnzea humilis modicella, Segmentina armi- 
gera and Carychium exile as the dominant mollusks. 
At Muncie is an excellent sample of dry upland association 
and near to it, a well-drained mesophytic association; unfor- 
tunately, the mollusk fauna was very limited in both species 
and individuals. This place no longer represents natural and 
normal habitats, being badly distorted and changed by hogs, 
cattle, horses and man. The stream at the Big Four R. R. 
crossing is very rapid, its bed being chiefly rock. On one side 
are high bluffs; on the other side is a broad, level flood-plain 
which exhibits several terraces. Numerous cut-offs occur, 
usually dry in Summer and Autumn. The small fauna of these 
is chiefly composed of Lymnia humilis modicella, L. caperata, 
Physa gyrina, Aplexa hypnorum, Planorbis trivolvis and Seg- 
mentina armigera. Mancassellus macrurus, Branchippus sp., 
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