168 ILLINOIS ACADEMY OF SCIENCE 
(Subgenus Galba Shranck, 1803) 
66. L. caperata (Say)—Urbana and Cottonwood Woods, 
Champaign Co., Muncie, Vermilion Co. Usually in temporary 
bodies of water, ponds, bayous and slowly moving streams, pre- 
ferring the outer zone where it lies among the vegetation and 
debris associated with Aplexa hypnorum, Physa gyrina and 
Sphaerium occidentale. Endures much dessication. 
67. L. palustris (Muller)—Urbana, Champaign Co., collee- 
tions of the Ill. State Lab. Nat. Hist. Young specimens were 
collected by me in 1910 in a creek feeding into the Salt Fork 
near a slaughter house at St. ean: The surfaces of these 
were much malleated. 
Subfamily Planorbinze 
GENUS PLANORBIS Muller, 1774 
Subgenus Hipeutis Agassiz in Charpentier, 1837 
68. P. exacuous Say—Crystal Lake, Urbana, Champaign 
Co. Similar in habits and habitat as P. parvus, associated with 
it. Sometimes it is found on lily pads. 
(Subgenus Gyraulus Agassiz [in Charpentier,] 1837) 
69. P. deflectus Say—Crystal Lake, Urbana, Champaign 
Co. On sticks, stones, and plants in quiet waters, usually in. 
deeper water than that preferred by parvus. 
70. P. parvus (S 
Urbana, and Salt Fork, Champaign Co. On stems of sub- 
merged plants and on objects in the water. Often in tangled 
masses of Spirogyra and other algae. Very abundant, often 
associated with P. exacuous. 
(Subgenus Helisoma Swainson, 1840) 
(Section Pierosoma Dall, 1905) 
71. P. trivolvis (Say)—White Heath and Monticello, Crys- 
tal Lake, Urbana, Salt Fork, St. Joseph, and Homer Park, 
Muncie, Hillery and Danville. Very abundant, crawling along 
muddy bottoms of streams, ponds, etc., on sticks, stones, 
aquatic plants, ete. Gregarious. Associated usually with 
Physa and Lymnaea. 
GENUS SEGMENTINA Fleming, 1817 
72. 8. armigera Say—Monticello, Piatt Co., Cottonwood — 
Woods, Crystal Lake and Urbana, Champaign Co., Muncie, 
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