50 WE. Ponder, D.J. Colgan, T. Terzis, S.A. Clark, A.C. Miller 
collect material for electrophoretic examination. In all, 77 samples were subsequently analysed. 
These results, combined with an analysis of shell measurement data for most of these samples, are 
presented here. Aspects of the genetic results obtained from the Dalhousie samples, particularly 
relating to gene flow, have been published elsewhere (Colgan and Ponder, 1994). 
In this paper three taxa are described, two congeners (the common snails found in the springs) are 
separated using allozyme differences, and a third is a member of a separate genus (Fluvidona) and is 
restricted to a few small seepages and cold outflows. 
Material and methods 
Collection. Material was collected by hand from many springs and each collection site for the 
Figure 1. Map of Dalhousie Springs showing the springs from which samples were obtained for this study 
