BAKER: FIELDBOOK OF ILLINOIS LAND SNAILS 11 



available in quantities; areas where granitic or volcanic rock 

 abounds are usually poor places for snails. Often, isolated wood- 

 lands in the midst of cultivated areas afford favorable snail 

 habitats. 



Snails abound on some of the highest Illinois hills and in 

 some of the deepest valleys; in comparatively dry places and in 

 swamps and marshes. Curiously enough, the rights of way of 

 railroads, especially embankments, afford good collecting lo- 

 calities, and a distinct fauna, evidently driven from the prairies 

 by the advance of civilization, has taken refuge in this environ- 

 ment. 



Most snails are associated with distinctive kinds of en- 

 vironment. Some are restricted to the heavy, virgin forests; 

 others are limited to the more open woodlands which have been 

 cut over. Many species are found in regions forested with oak, 

 maple, willow and other deciduous trees; only a few are asso- 

 ciated with coniferous trees. Some are found in abundance on 

 and near limestone cliffs, whereas others are more or less re- 

 stricted to the vicinity of bodies of water, or the bottom lands 

 or fioodplains of rivers and streams. Some, as the amber snails 

 of the genus Succinea^ live among cattails bordering ponds 

 and streams and may be found even in the water; these snails 

 are in a measure amphibious. A few snails are found on prairies 

 in the grass, but the fauna of such places is not large. No 

 pulmonate mollusk will live where sand, lime or ashes in a pure 

 state are found. A few typical habitats are shown in the illus- 

 trations contained in this volume. 



Collecting Land Snails 



Perhaps the best place to find snails, especially the small 

 species, is under loose or started bark of fallen tree trunks that 

 have been lying on the forest floor so long that the wood has 

 become somewhat rotten. Here both individuals and species of 

 land snails are usually abundant. As many as 15 different kinds 

 of snails have been found in one such favorable location. In the 

 shelter of rocks or boulders may often be found a number of the 

 smaller snails called pupoids. Under leaves, in old brush piles, 

 under old boards near sawmills, and under and in the general 

 debris of the forest floor these animals may usually be found. 

 Sometimes the larger species may be seen either crawling upon 

 or clinging to tree trunks, and many times in wet weather snails 



