102 



LAND AND FRESH WATER MOLLUSKS 



FIG. 79. Physa 

 gyrtnav&r. hild- 

 rethiana Lea. 



Physa hildrethiana LEA, oleacea Tryon, and albofilata Ancey, are united by 



Crandall with this species. 

 Physa fontinalis J. DE C. SOWERBY (in Richardson), not of Linne. 



Range. The United States east of the Mississippi, 

 Canada, and northward. 



Manitoba ! Lower Saskatchewan near Lake Win- 

 nipeg ! York Factory, Keewatin ; Great Slave Lake ! 

 Methy Lake to Great Bear Lake (Richardson) . 

 Variety oleacea Tryon, also variety hildrethiana 

 Lea : Great Slave Lake ; Port Clarence, Alaska (Bean) . 

 This is the prevalent species over the north country, 

 extending to the Arctic Circle at Great Bear Lake, 

 and westward to Bering Strait. It is to be noted 

 however that Physa in this region is nowhere a common form like 

 Lymncea or Planorbis, or even Aplexa. The varieties noted differ 

 from one another and from the typical form chiefly in the character 

 of slenderness. 



Physa ancillaria Say. 



Physa ancillaria SAY, Journ. Acad. Nat. Sci. Phila., v, p. 124, 1825. 



HALDEMAN, Mon. Limn., p. 27, pi. in, figs, i-io, 1843. GOULD, Inv. 



Mass., p. 213, fig. 142, 1841. CRANDALL, Nautilus, xv, No. 4, p. 42, 



1901. 

 Physa vinosa GOULD, and P. crassa WALKER, are regarded as subspecies of 



P. ancillaria by Crandall, and Binney unites with it P. obesa De Kay. 



Range. The United States northward from the Potomac and Ohio 

 Rivers, and east of the Mississippi, to the Saskatchewan. Variety 

 vinosa Gould, Lake Superior. 



Manitoba. Lake of the Woods ; Lake Winnipeg ; and the lower 

 Saskatchewan River. 



The above localities are cited from the literature ; I have seen no 

 specimens from north of the United States, west of Ontario. 



Physa lordi Baird. 



Physa lordi BAIRD, Proc. Zool. Soc. London, for 1863, p. 68. BINNEY, 



Land and Fw. Sh. N. Am., 11, p. 76, figs. 125-127. 

 Physa parkcri CURRIER, in Decamp, List of Shellbearing 



Moll, of Mich., Kent Sci. Inst. Misc. Pub., v, p. 15, 



pi. I, fig. 3, 1 88 1. 



Range. Washington and British Columbia, east 

 of the Cascade Mountains, eastward to the northern 

 peninsula of Michigan, and southward at high alti- 

 tudes to New Mexico. 



Round Lake ! Lake Houghton ! and Lake Douglas ! FlG 8o p/, ysa 

 northern Michigan ! Mingusville, Montana ! Ft. Col- i or di Baird. 



