fauna, have been drawn upon whenever necessary. This field- 

 book, therefore, embodies all the present state of knowledge 

 concerning the number of Illinois species of land snails and their 

 distribution throughout the state. 



The introductory chapter of this fieldbook contains inter- 

 esting and useful information on the general characteristics of 

 Illinois land snails — where they live, how they grow and how 

 they may best be collected and studied. 



In the descriptive section of the book, an attempt has been 

 made to present a simple account of each species of land snail 

 found within the state. Each species is illustrated by a figure 

 or figures accurately drawn to show its characteristics. 



Keys to families and genera have been included to aid in 

 the identification of species. Students unfamiliar with keys 

 should consult the paragraphs on their use in the introductory 

 chapter. 



The description of each species of snail has been made brief, 

 and only the important features that distinguish one species 

 from another have been mentioned. The habitat preferences of 

 the species as they occur in Illinois are noted. 



The drawings for the illustrations are the work of Dr. Carl 

 O. Mohr, Associate Entomologist and artist with the Natural 

 History Survey. It is felt that the inclusion of mostly new and 

 original drawings, instead of copies of time-worn illustrations 

 made many years ago, will be welcomed by all students of the 

 Mollusca. Of the shell or animal figures, all but those at the 

 top of pages 88 and 120 and on page 143 were drawn from 

 specimens. 



Adapting the manuscript to the same general format as the 

 Illinois Natural History Survey Manual 1, Fieldbook of Illinois 

 Wild Flowers, as well as its general styling and indexing, has 

 been the work of Mr. James S. Ayars, editor for the Survey. 



It is the hope of those engaged in the preparation of this 

 fieldbook that its publication may stimulate the study of an 

 interesting subject not only among young people in schools and 

 colleges of the state but also among individuals of all ages who 

 find pleasure in exploring the mysteries of the out of doors. 



Theodore H. Prison 



Chief 

 Urbana 

 January 16, 1939 



