FAMILY LYMN^EID^E 



8 7 



FlG. 64. Plan- 

 orbis bicarina- 

 tus Say. 



of trivolvis such as occur in the north and east, if not throughout the 

 range of the latter. 



Planorbis (Helisoma) bicarinatus Say. 



Planorbis bicarinatus SAY, Nicholson's Encycl., ist ed., vol. n (no pagina- 

 tion), No. 2, pi. I, fig. 4, 1817 (Lake Erie) ; not of Lamarck, 1822.- 

 BINNEY, Land and Fw. Sh. N. Am., n, p. 123, fig. 205, 1865. 



Helix engonata RACKETT, 1822 ; + Planorbis engonatus CONRAD, 1834. 



Range. The United States east of the Rocky Mountains ; east- 

 ern Canada. 



Lake Superior to Lake Winnipeg ! Lake Manitoba ; Moose Fac- 

 tory, Hudson Bay ! the lower Saskatchewan River at Grand Rapids ! 

 Knee Lake, Keewatin ! Portland, Oregon ! Yaqui 

 River, W. Mexico ! 



This well defined species has probably been carried 

 down stream from the sources of the Columbia River, 

 in the same manner as some other east American spe- 

 cies. It cannot be regarded as permanently estab- 

 lished on the Pacific slope, as yet. It varies consider- 

 ably in size, and for exceptionally developed specimens 

 from Benzie Co., Mich., Walker has proposed the 

 varietal name major. 



Planorbis (Pierosoma) corpulentus Say. 



Planorbis corpulentus SAY, Long's Exp., n, p. 262, pi. xv, fig. 9, 1824 (not 

 of Binney et al.) BRYANT WALKER, Nautilus, xiii, No. 12, April, 

 1900, pp. 133-138. 



Range. Northern Ontario from Lake Simcoe to 

 Rainy Lake, Lake of the Woods, Winnipeg River 

 and Lake ! to Vermilion Lake, Lat. 56 30', in 

 Athabaska. 



Knee Lake, Keewatin ! Isle a Lacrosse Lake ! and 

 English River ! Rat Portage ; northern Michigan and 

 Minnesota. 



This well marked species was unknown to Binney, 

 and has been united mistakenly with trivolvis and 

 others. It belongs to the colder northeastern portion 

 of the continent and its complete range is yet un- 

 known. It has not been identified from the region west of the Rockies. 

 Mr. Walker's note on this species may be consulted with profit. 



Planorbis (Pierosoma) binneyi Tryon. 



Planorbis binneyi TRYON, Am. Journ. Conch., ill, p. 197, 1867. HALDE- 

 MAN, Mon. Limn., 19, pi. in, figs. 7-9, 1844. BINNEY, Land and Fw. 

 Sh. N. Am., n, p. 103, fig. 175, 1865. 



FIG. 65. Plan- 

 orbis corpulen- 

 tus Say. \. 



