276 College of Forestry 
47. Ancylus parallelus Haldeman. Fig. 45, No. 17. 
Observed at three stations, always more or less protected. 
In the Saginaw Bay region it was observed, in quiet coves 
and ponds, on the under side of lily leaves. In the Georgian 
Bay region it was collected from the under side of lily 
leaves and on sticks. Beauchamp records it “on plants ” 
from Onondaga County. It is as widely distributed through- 
out the United States as are the last two species. It has 
been collected from the following plants: 
White Water Lily (Castalia odorata). Under surface. 
Yellow Water Lily (Nymphea advena). Under surface. 
Bur-reed (Sparganium eurycarpum). Dead leaves used as food. 
A species of Ancylus has been observed on two species of 
pond-weed (Potamogeton americanus and P. amplifolius). 
Ancylus is eaten by the Common Bullhead. 
Famity PLANORBID®. 
Genus Pianorsis Miiller. 
48. Planorbis trivolvis Say. Fig. 46, Nos. 13-16. 
Collected from eight stations, all protected, where the 
mollusks were usually among vegetation. This, the com- 
monest of all ‘ wheel snails,” is widely distributed from the 
Rocky Mountains to the Atlantic Ocean and from Canada 
southward. As observed in other places trivolvis is always 
an inhabitant of quiet, even swampy and stagnant, pools and 
water bodies. At Isle Royale it was found in a pool in a 
tamarack swamp (p. 292). In the Saginaw Bay region, it 
occurred on lily leaves, among dead vegetation, on driftwood, 
ete., in pools, marshes and swamps. It was noted that the 
shells from the Bay were larger and heavier than those from 
inland waters (p. 165). In the Georgian Bay region it was 
observed in protected bays, along the shore in water less than 
two feet deep (p. 100). Trivolvis is the commonest. shell 
in many parts of New York State. Listed by Beauchamp. 
Observed on the following plants: 
White Water Lily (Castalia odorata). On leaves and stem. 
Yellow Water Lily (Nymphea advena). On leaves and stem. 
Cat-tail (Typha angustifolia). Dead leaves used as food. 
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