20 ILLINOIS NATURAL HISTORY SURVEY MANUAL 



of a stadium, a rostrum, an auditorium. Scientific names be- 

 come simple when we understand and use them frequently. 



Another reason for using Latin and Greek for scientific 

 names is that these languages are more nearly universal than any 

 others. Use of them allows the form of the name to remain un 

 changed. The name Polygyra albolabris is clearly understood by 

 conchologists of almost any nationality, while the name many- 

 whorled^ white-lipped snail might mean nothing to anyone except 

 American or English students. 



Pronunciation of scientific names. — Although scientific 

 names are of Greek or Latin derivation or form, they are pro- 

 nounced in the United States as if they were of English origin. 

 Students who have learned the Latin pronunciation common 

 today in public schools of the United States sometimes experi- 

 ence more difficulty in sounding scientific names than do those 

 who have studied only English. Just as in English, the letter g 

 is pronounced sometimes as in green and sometimes as in gentle; 

 c sometimes as in cat and sometimes as in cell\ v like the English 

 V rather than the English w. Guides to pronunciation may be 

 found in the introductory section of Webster's New International 

 Dictionary under "Rules for the English Pronunciation of Latin." 



Divisions of snails. — Snails, like all other groups of animal 

 life, are separated into divisions according to different char- 

 acteristics that several may have in common. These divisions 

 are class^ order^ family^ genus and species. Thus our white- 

 lipped snail, the species Polygyra albolabris (Say), belongs to the 

 class Gastropoda, or snails; the order Pulmonata, or snails that 

 breathe air by means of a lung and that have certain charac- 

 teristics of the internal organs in common; the family Poly- 

 gyridae, or group containing all of the snails that have teeth, 

 internal organs and shell more or less like our white-lipped 

 snail; and the genus Polygyra, to which belong the snails more 

 intimately related to our snail. The whole system of nomencla- 

 ture is simple, and the amateur conchologist need have no fear 

 concerning his ability to comprehend it. 



How to Identify Land Shells 



The young collector of Illinois land snails will naturally 

 ask, "How am I going to find out what species I have collected? 

 Must I run through the entire book to see if my specimen 

 matches a certain description or figure?" Such a question is 



