42 LAND AND FRESH WATER MOLLUSKS 



hanimonis Strom ( 1765), but Strom's figure is widely umbilicated and 

 so rude as to be practically unidentifiable. 



The first specific name which unmistakably applies to our shell, and 

 to it alone, is the trochiformis of Montagu, which it seems advisable 

 to adopt. 



Under the name fidva several distinct though very closely allied 

 forms have been generally included. Reinhardt, Bourguignat and 

 lastly Pilsbry have thrown additional light on this subject, and a num- 

 ber of species or marked varieties are now recognized. The Helix 

 chersina of Say is a southern form, while the H. egena of Say is 

 generally admitted to be a synonym of the trochiformis. 



The Eucomilus fabricii of Greenland seems to be merely a case 

 i.f an offshoot which by isolation has been enabled to assume distinctive 

 characters, which have hardly reached a greater than varietal rank. 



Genus Zonitoides Lehmann. 



Zonitoides nitidus Miiller. 



Helix nitida Muller, Hist. Verm., II, p. 32, 1774. 



Helix lucida Draparnaud, Hist. Moll, de France, p. 103, 1805 ; not of the 



Tableau, 1801. 

 Hyalina nitida Tryon, Am. Journ. Conch., II, p. 250, pi. IV, fig. 24, 1866. 



— BiNNEY, Land and Fw. Sh. N. Am., i, p. 31, figs. 35, 36, 1869. 

 Zonitoides tiitidiis Pilsbry, Class. Cat., p. 27, 1898. 



Range. — Ilolarctic. Europe, northern United States, British 

 America, Alaska, Japan. 



Red River drift, Manitoba ; Peace River, Athabaska ; Fort Resolu- 

 tion, Great Slave Lake; Seattle, Wash. ! Klukwan, Alaska (Krause). 



This sjDecies has been found so widely spread that it cannot reason- 

 ably longer be regarded as merely a European emigrant. 



Zonitoides arboreus Say. 



Helix arboretis Say, Nicholson's Encyl., ist Am. edition, pi. iv, fig. 4, 1817. 

 Helix arborea Gould, Inv. Mass., p. 182, fig. no, 1841. — Morse, Am. Nat., 



I, p. 542, fig. 30, 1867. 

 Hyalina arborea Morse, Journ. Portland Soc. Nat. Hist., I, p. 14, fig. 28, pi. 



VI, fig. 29, 1864. — Binney, Land and Fw. Sh. N. Am., i, p. 33, figs. 38- 



40, 1869. 

 Helix breweri "H-EViCOyili, Proc. Cal. Acad. Sci., Ill, p. 118, 1864. 



Range. — North America generally and Japan. 



Labrador ; Ontario ; English River ! Keewatin and Moose Factory ; 

 Carberry and Lake of the Woods, Manitoba ; Laggan and Red Deer, 

 in Alberta ; Great Slave Lake ! Oregon, at Weston ! Vancouver Island 

 at Victoria ! Departure Bay ! Nanaimo ! Comox ! Union Bay ! etc. ; 

 in Alaska at Unalaska ! Petropavlovsk, Kamchatka! Japan (Hirase). 



