22 



PROCEEDINGS OF THE ACADEMY OF 



[Jan., 



of Michigan, the fact of these references to a small form of Polygyra 

 albolabris raised a question as to whether there was really a small 

 race in Michigan worthy of varietal distinction or not, and led to the 

 investigation, the results of which are embodied in this paper. 



The material used consisted of 511 specimens, contained in six 

 distinct sets as follows: 



Fig. 1. 



I. Two hundred and twenty-five specimens, representing the writer's 

 collection of Michigan albolabris. These shells are from all parts of 

 the State. It contains 53 separate lots, varying from 1 to 11 in number, 

 from 38 of the S3 counties of the State. The accompairying chart 



