152 ILLINOIS ACADEMY OF SCIENCH 
Baker’s catalog of the mollusks of [llinois (1906) lists one 
species from Piatt Co., twenty-three from Champaign Co., and 
four from Vermilion Co. The present paper lists fifty-two, 
seventy-eight and sixty-seven species respectively, a total of one 
hundred and sixteen species. The important fact to note is that 
the material on which this paper is based was collected at odd 
times, and nearly always when engaged in entomological work. 
An exception to this is the Brownfield Woods (also known as 
the Augerville Woods) near Urbana, where a special study was 
made of the ecology of forest inhabiting snails for a thesis. It 
is clear that this paper cannot be considered as even fairly 
complete, for if an intensive survey is made, the number of 
species will probably be over two hundred. 
Primarily as a stimulus to others, in the hopes that we may 
know more of the ecology of our mollusk-fauna, I prepared a 
map of Illinois on which I summarized our knowledge of this 
fauna to date. In the preparation of this map I followed the 
data given by Baker and that in this paper. There are only 
five counties with more than one hundred species reported 
from them, and what is most regretable, there are thirty-two 
counties of which we have no record at all. Almost one-third 
