A New Interglacial Pulmonate Mollusc From the Province of Saskatchewan

Included in a collection of interglacial molluscs fiom the Province of Saskatchewan, submitted for identification by the Canadian Geological Survey, there is one form which appears to be worthy of special mention. This is a variety of Lynmnaea vahlii (Beck M6ller) which is undescribeed. While the determination of the members of the family Lymnaeidae on the, basis of the shell characters alone, is sometimes rather difficult, this form is sufficiently distinct to merit its description as a new subspecies. The relationships of this fossil to the other species of the genus, such as L. palustris (Muiller), are not known, and this new form is provisionally placed under L. vahlii pending the completion of detailed investigations of the variation of the members of this group. The use of the generic name Lymnaeca is retained as indicating the general relationships of these animals.