LYMN^EID^E OF NORTH AMERICA. 253 



bution of this tiny species that no generalization can be made at this 

 time. It may ultimately be found to inhabit the greater part of the 

 United States east of the Rocky Mountains and west of the Alle- 

 ghanies, and to be coextensive with Galba parva. 



RECORDS. 



ARIZONA: Ash Canyon, Huachuca Mts., 5000 ft. alt., Cochise Co. (Ferriss 

 and Daniels). 



ILLINOIS: Rockford, Winnebago Co. (Hinkley) ; Copperas Creek (E. 

 Hall); Northern Illinois, in drift (Sterki). 



INDIANA: Lake Maxinkuckee, Marshall Co. (Bartsch) ; Arlington, Mar- 

 shall Co. ; Waterford and Little Kankakee River, La Porte Co. ; Marsh, west 

 side Lake James, Steuben Co. (Daniels). 



IOWA: Lost Island Lake and swamps, Ruthven, Palo Alto Co. (Walker). 



KANSAS: Lawrence, Douglas Co., in greenhouse; Tecumseh, Shawnee Co. 

 (Hanna). 



MICHIGAN : Gratiot, Isabella, Kent, Marquette, Montcalm, St. Joseph, Tus- 

 cola and Washtenaw Counties (Walker). 



MONTANA: Great Falls, Cascade Co. (Bailey); Beaver Creek, Mingus- 

 ville and Wibaux, Dawson Co. (Squyer). 



NEW MEXICO: Flood debris, Arroya Pecos, Las Vegas, San Miguel Co. 

 ( Cocker ell ); drift of Rio Grande, Paraje, Socorro Co. (Cockerell). 



OHIO : Between Dover and Rocky River, near Cleveland, Cuyahoga Co. ; 

 Put-in-Bay Island (J. A. Allen) ; Cartalea, Erie Co., in creek near depot 

 (Sterki). 



GEOLOGICAL RANGE : Pleistocene. 



Marl beds of Arnolds Lake, Washtenaw Co., Michigan (Walker). 



ECOLOGY : Found in situations similar to those occupied by Galba 

 parva. 



REMARKS : This little species, the smallest of our American 

 Lymnseas, is related to Galba parva, appearing at first sight to be a 

 small example of that species. It differs from parva in its smaller 

 size, rounder and more turreted whorls, slenderer outline, longer and 

 narrower aperture and smaller and less conspicuous umbilicus. The 

 whorls are inclined to be shouldered, also, a feature not emphasized 

 in parva. There is some variation in the length of the spire, many 

 specimens having a rather long spire, while in others the spire is much 

 depressed and the whorls are humped, this last being in slightly ab- 

 normal forms. The inner lip of dalli is different from that of parva, 

 being generally more erect ; in dalli there is also a denting in or con- 

 striction at the point of juncture of the inner lip and the parietal 

 wall which is not notably apparent in parva. 



In the Nautilus (XX, p. 52) this species was described as the 

 parva of Lea, but a careful study of Lea's types in the Smithsoniaa 

 Institution makes it evident that it is not that species, but a new one 



