THE NAUTILUS. 65 
Succinea grosvenori Lea. 
Suceinea lineata Binn. 
LIMNASACEA. 
Family LIMN AIDE. 
Limnea palustris Mull. 
Limnea bulimoides Lea. 
Timneea humilis Say. 
Timnea caperata Say. 
Planorbis bicarinatus Say. 
Planorbis lentus ? Say ; young shells only. 
Planorbis parvus Say. 
Planorbis umbilicatellus Cockerell ; (P. wmbilicatus Taylor, Leeds 
Journ. Conch. IV, p. 351, 1885, not of Miller, 1774). Described 
from Manitoba. 
Family ANCYLIDZ. 
Ancylus rivularis Say, one specimen. 
Family PHYSIDZ:. 
Physa gyrina Say, young only. 
Physa ancillaria Say. 
Physa heterostropha Say. 
Physa lordi Baird. 
PELECYPODA. 
Family CORBICULID 2. 
Spherium suleatum Lam. 
Pisidium compressum Prime. 
Family UNIONIDA, 
Anodonta plana Lea, young. 
Anodonta ovata Lea, young. 
Only one perfect and adult specimen of Planorbis umbilicatellus 
was obtained in the river drift. It is readily distinguished from 
P. parvus Say by its narrow funnel-shaped umbilicus and higher, 
somewhat beveled whorls. It was first collected in Manitoba by 
R. M. Christy, Esq., and described by Taylor under a name al- 
ready widely known in the literature though generally regarded as 
a synonym of one or another Linnean species. It was re-named by 
Cockerell, in the Conchologist’s Exchange, November, 1887, p. 68. 
CW. i. D.). 
