34 ILLINOIS NATURAL HISTORY SURVEY MANUAL 



from foreign countries into greenhouses and other places in 

 cities. The native fauna, therefore, comprises 116 species and 

 races. These are divided among 14 famihes and 28 genera. 



It is of interest to compare this fauna with that of other 

 states. The modern classification and nomenclature of the 

 land MoUusca represent such changes from those in use a few 

 years ago that only five catalogs are at present available for 

 direct comparisons. These relate to the fauna of Michigan 

 (Winslow, 1936), Ohio (Sterki, 1907), Pennslyvania (Brooks, 

 1931), Indiana (Daniels, 1904, 1915) and Alabama (Walker, 

 1928). It is probable that additional species of MoUusca will be 

 found in Indiana, bringing the number of species and races of 

 that state to approximately the total of those in Illinois. 



Comparisons of two genera, Polygyra and Gastrocopta^ show 

 the large Illinoian fauna of these important groups. Table 1 

 compares graphically the total land snail fauna, the polygyras 

 and the gastrocoptas of the six states in which the MoUusca 

 have been most carefully studied. Alabama alone exceeds Illinois 

 in the number of species represented. 



Table 1. — Total number of species, subspecies, races and vari- 

 eties of MoUusca and of two important genera reported from six 

 states. 



Total , . 



State XT I Polygyra Gastrocopta Authority Date 



It is possible that a few additional species may be found to 

 inhabit Illinois, especially the northern portion bordering Wis- 

 consin and the eastern adjoining Indiana. 



