LYMN EID OF NORTH AMERICA. 455 
ville, mentioned by Dall (p. 71) are referred by the writer to binneyi 
(see page 443). 
Galba alaskensis Baker. Plate XLVI, figures 14-15. 
Limnea scalaris WeESTERLUND, Nach. Mal. Ges., IV; p. 165, 1883; Vega 
Exped., Vert. Iakt., IV, pp. 163, 170, 201, pl. 4, fig. 13, a, b, 1885 (not scalaris 
A. Braun, 1853, or Sowerby, 1872). 
Lymne@a emarginata Dat, Alaska Moll., p. 69, 1905. 
SHELL: Elongated, thin, fragile, pellucid; periostracum light horn 
colored; surface shining, sculpture of coarse growth lines crossed by 
impressed spiral lines; whorls 6, convex, especially the body whorl; 
sutures deeply impressed; spire long, acute; the spire whorls are ab- 
ruptly narrowed and constricted above the body whorl; aperture long 
ovate or semicircular, a trifle shorter than the spire, roundly arched 
above, subtruncated below; inner lip narrow below, widening above 
to form the columellar callus which is heavy ; the inner lip is appressed 
tightly at its junction with the parietal wall and forms a distinct as- 
cending plait; the umbilical chink is narrowly open and is emargined 
by the inner lip. 
Length. Breadth. Aperture length. Diameter. 
22.00 10.00 9.00 6.00 mill. 
23.00 12.00 10.50 Be 
Tyres: Location not ascertained. 
Type Locauity: Port Clarence, Alaska. 
ANIMAL, JAW, RADULA and GENITALIA: Unknown. 
RANGE: Alaska. A species of the Yukonian region and of the 
Arctic life zone. 
; RECORDS. 
ALASKA: Port Clarence (Westerlund). 
GEOLOGICAL DISTRIBUTION: Unknown. 
Ecotocy: Not recorded. 
RemMarKS: Alaskensis (scalaris) is undoubtedly a valid species 
and not a synonym of emarginata, as thought by Dr. Dall. Its narrow 
shell, acute spire, very deep sutures, causing tumid whorls, and its 
regularly long, ovate or semicircular aperture will at once separate it 
from any form of Galba emarginata canadensis, to which race it has a 
superficial resemblance. It is totally unlike Say’s figure of emarginata 
besides which it occupies an entirely different river system. Young 
specimens might be confused with juvenile forms of randolphi, but 
could be easily distinguished by the more tumid whorls, deeper sutures 
and generally narrower shell and aperture. It somewhat resembles 
petersi, but may be known by its narrow shell and more tumid body 
whorl, besides differing in the form of the inner lip. 
