BAKER: FIELDBOOK OF ILLINOIS LAND SNAILS 9 



the fruit of the horsetail are often part of their diet. They will 

 not eat pungent plants of any kind. Not all snails eat vegetable 

 matter. A few are carnivorous and feed upon earthworms, 

 leeches or other snails. 



Because the body of the land snail is peculiarly shaped to 

 fit into the coiled shell, the digestive, circulatory, locomotor, 

 nervous and reproductive organs are not so easily recognized and 

 studied as those of many other animals. But all of these sys- 

 tems are found in the land snail, and in the various species they 

 often show individual patterns which add evidence to the 

 differences based on form and size of shell. 



How Snails Reproduce 



In a small cavity in our old log, we note a mass of jellylike 

 globules, eggs which have been laid by the white-lipped wood- 

 land snail, Polygyra albolabris. All Illinois land snails lay eggs, 

 which vary in number from a few to 40 or more, in moist locali- 

 ties where they are protected from the sun's rays. The eggs may 

 be found hidden under old logs, especially those on which the 

 bark is loose, under chips, leaves, pieces of peeled-ofF bark and all 

 sorts of debris. May and June are the usual periods during 

 which land snails lay their eggs. Twenty or 30 days later, the 

 young snails hatch and start on their life journey, reaching full 

 maturity in about two years. Some land snails do not lay eggs 

 but give birth to fully formed young. However, no species with 

 this birth habit are found in Illinois. 



Lung-breathing land snails, the only kind considered in 

 this fieldbook, are hermaphroditic; that is, both sexes are in the 

 same animal, the sexual organs being closely associated in the 

 body, and the external openings of both sexes being merged in 

 one opening. Study of the variation of the organs in the different 

 species aids greatly in the classification of the land snails. 



Where Land Snails Live 



Land snails may be found almost everywhere, even in 

 places where the dry nature of the habitat would seem to exclude 

 life of any kind. Forested river valleys are perhaps the most 

 favorable habitats for snails, especially those valleys having 

 outcrops of limestone rock. The largest, most highly colored 

 shells of the various species of land snails are found where lime is 



