The Relation of Mollusks to Fish in Oneida Lake 273 
Physa ancillaria warreniana has been observed on the fol- | 
fowing vegetation, using it for either support or food, 
probably both: 
Broad-leaved Arrow-head (Sagit- White Water Lily (Castalia odor- 
taria latifolia). ata). 
Pickerel-weed (Pontederia cor- Yellow Water Lily (Nymphaa ad- 
data). vena) . 
Water Willow (Dianthera ameri- Green filamentous algie. 
cand). Water Celery (Vallisneria spira- 
American Bulrush (Scirpus ameri- lis). 
canus). Dead leaves used as food. 
Probably feeds on desmids, diatoms, and green algze, and 
is eaten by the Pumpkinseed and Golden Shiner. Under 
the generic name Physa, this type of snail is eaten by eleven 
kinds of fishes: Dogfish, Common Whitefish, Common Red 
Horse, Yellow Bullhead, Common Bullhead, Mud Minnow, 
Willifish, ‘Top Minnow, Viviparous Minnow, Bluegill, and 
Pumpkinseed. 
43. Physa integra Haldeman. Fig. 45, No. 36. 
Observed at five stations, on a bouldery exposed point or 
im a sandy exposed bay. The species is here large and 
typical. It is widely distributed throughout the Great 
Lake and St. Lawrence River region. In the Saginaw Bay 
region it is found among alew (Vaucherta) and on the under 
side of lily leaves in ereeks and rivers, in contrast with the 
exposed habitats in Oneida Lake. In the Georgian Bay 
region the variety neagarensis, a smaller shell, occurs on 
exposed rocky shores. It is a common species in New York 
State where it seems to be better known under the name 
of its race niagarensis, under which name it is lsted by 
Beauchamp. 
44. Physa gyrma Say. Fig. 45, No. 41. 
This Physa was observed only at two stations, both quiet 
water habitats. It is characteristic of swampy areas where 
the water is more or less stagnant. Gyrina is widely dis- 
tributed over the central and eastern parts of the United 
