100 LIMNZA. 
** Shell small, narrow, with elevated spire. 
+ British and Danish American Species. 
15. LIMNZA ARCTICA, Lea. 
Plate 17, fig. 9. 
Shell elliptical, somewhat inflated, rather 
thick, not umbilicate, minutely striate, pale 
horn-color ; spire obtuse, decorticated ; sutures 
impressed ; whorls convex; aperture broadly 
elliptical, rather large; outer lip regularly ex- 
panded; columella thickened in the middle 
and furnished with a large fold. 
Length 10, diam. 6 mill. 
Moose River of Hudson’s Bay, Arctic 
America. 
16. LIMNAA VAHLII, Beck. 
Plate 17, fig. 10. 
Shell ovate, convex, spire moderate, apex 
obtuse, decorticated ; whorls six, with well- 
marked sutures; aperture large, ear-shaped, 
(74) 
