Limnaea pallida. Adams. A beautiful white shell in 

 Onbndaga and Cross lakes, where most shells are 

 light colored. 



hurailis. Say. Brown, common, our smallest local 

 species. 



The translucent shining shells of the following two gene- 

 ra, revolve in the opposite way to most others. 



Physa ancillaria, So.y. Large, inflated, spire depressed. 

 Skaneateles. 



heterostropha. Say. Less inflated and depressed, 

 common, thinner. 



Niagarensis. Lea. Similar, smaller, colorless, rare. 

 Onondaga lake. 



gyrina. Say. Cylindric, yellowish, aperture long. 

 Forest ponds. There are several varieties, one like 

 P, Hildrethiana. 



Bulinus hypnorum. L. Thin, slender, brown, shining. 

 Wet w r oods. 



The following two genera are flat orbicular shells of the 

 Planorbis family, feeding on decaying vegetation in still 

 waters. 

 Planorbis campanulatus. Say. Bell-shaped aperture, 



common. 



trivolvis. Say. Our largest species, common. 



lentus. Say. Similar, more depressed, rarer. 



bicarinatus. Say. Whorls sharp above and below? 



common, 



exacutns_ Say. Small, thin, margin acute, com- 

 mon. Swamps. 



dilatatus. Gould. Small, perforation deep. Doubt- 

 ful identification. 



deilectus. Say. Small, mouth depressed. Wet 



woods. 



albus. Mall. Thin, yellow, hairy, common. 



parvus. Say. Corneous, common. Oar smallest 



species.. 

 Segrrientina armigera. Say. Olive, aperture with teeth. 



Wet woods. 



The next genus is of the small pyramidal fresh water 

 limpets, clriging to stones and plants. Not abundant. 



Ancylus rivularis. Say. Seneca river, rare. 



tardus. /Stey. --Olive, on stones in rivers. 



