11 



VALLONIIDAE 



VALLONIA PULCHELLA (MiJller) 



The shell of the snail Vallonia pulchella is little more than 

 one-sixteenth inch (2.0-2.5 mm.) in diameter. It is a glassy 

 white in color and is almost transparent. The base of the 

 shell and the umbilicus are round. 



Apparently common in all parts of 

 Illinois, Vallonia pulchella has a va- 

 riety of habitats: floodplain areas of 

 streams in woods of oak and elm; 

 isolated woodlands of oak, elm, hick- 

 ory, w^alnut and beech; and railroad 

 embankments, among grass and bushes. 

 In the woods it is found about debris 

 and on wet logs. This snail has a wide 

 distribution outside of North America, 

 including Europe, Asia and northern 

 Africa. It is distributed over most 

 parts of the United States; however, 

 Vallonia pulchella is not found in territory bordering the Pacific 

 Coast. It is said to occur with Vallonia excentrica. 



VALLONIA EXCENTRICA Sterki 



Slightly smaller than Vallonia pulchella, the shell of Val- 

 lonia excentrica is about one-sixteenth inch (2 mm.) in diame- 

 ter. It may be recognized by the form of the umbilicus, which 

 is much elongated and very sharply 

 expanded near the last half of the 

 body whorl. The translucent, straw- 

 colored shell as seen from the base 

 is not regularly circular, but is ovate. 

 The name excentrica is given because 

 of these peculiarities. 



In Illinois, this snail, known as the 

 eccentric Vallonia, has been reported 

 only from Champaign County, on the 

 south side of the University of Illinois 

 campus and in the yard of Dr. H. J. 

 Van Cleave, Urbana. It is known 

 from Europe and parts of America. 



