FAMILY PHYSID^E 107 



Physa elongatina LEWIS, Proc. Boston Soc. N. Hist., v, pp. 122, 298, 1855. 

 Aplexus hypnorum CHENU, Man. de Conch., I, p. 481, fig. 3556, 1859. 

 Bulinus hypnorum BINNEY, Land and Fw. Sh. N. Am., n, p. 99, fig. 170, 



1865. 

 Bulinus hypnorum var. picta KRAUSE, Sitzb. Ges. Naturf. Fr. zu Berlin, 



1883, p. 32. MARTENS, Conch. Mitth., n, p. 184, 1885. 

 Physa hypnorum var. Polaris WESTERLUND, Sib. 1. u. Sottv. Moll., p. 56, 



1877. MARTENS, Conch. Mitth., n, p. 184, 1885. 

 Physa (Nauta) hypnorum LINNE. WESTERLUND, Fauna Palaarct., Reg. v, p. 



57, 1885. 

 Physa (Nauta) hypnorum var. polaris WESTERLUND, op. eft., p. 58. 



Range. Northern Europe, Asia and America, Northern United 

 States and Canada. 



English River, Manitoba. Red Deer, McLeod, Olds, etc., in Alberta. 

 Great Slave Lake, at Fort Resolution ! York Factory, Hudson Bay ! 



Yukon River, at old Fort Yukon ! and Nulato ! 

 Alaska ; Porcupine River in Alaska ! also Port Clar- 

 ence ! and the Nushagak River. 



Snake River, Idaho ! Middle Park, Colorado ! Up- 

 per Missouri in Montana ! Utah (Hemphill) ! 



This well known species is supposed to be circum- 

 boreal, but there are some peculiarities in its known FlG g x 

 distribution. While it extends to northern and west- lexa hypnorum. 

 ern Alaska and down into the mountainous region in 

 Colorado and Utah, it has not been reported so far, authentically, from 

 west of the Cascades, either in the United States or British Columbia. 

 There was one record " near Puget Sound " by Dr. J. G. Cooper, which 

 is cited by W. Cooper and Carpenter, but this refers to a shell obtained 

 at Vancouver, Wash, (not Vancouver Island) , by Sir George Simp- 

 son, which was afterward described by Dr. Lea as Physa hordeacea. 

 It is not positively known that this species is not a Physa, though 

 Tryon has referred it to Bulinus ( = Aplexa) , on the strength of its 

 general aspect. 



A number of varieties have been proposed, but there is not much 

 systematic basis for such of these mutations as I have seen. 



Genus Ancylus Miiller. 



Subgenus Ancylus s. s. 



Patella (sp.) LINNE, Syst. Nat., ed. x, p. 783, 1758. 



Ancylus GEOFFROY, Traite som. des Coq. Fluv. Paris, pp. 122, 124, 1767 ; not 



binomial, sole example Patella lacustris Linn6. Ibidem, translation by 



Martini, pp. 108, no, 1767. 

 Ancylus O. F. MULLER, Hist. Verm., n, p. 199, 1774, A. lacustris and 



fluviatilis Miiller ; Zool. Dan. Prodr., p. 237, 1776. DRAPARNAUD, 



Tabl., pp. 30, 46, 1801 ; Hist, des Moll. Terr, et Fluv. de France, pp. 



