LAND SNAILS 



Introduced From Foreign Countries 



In greenhouses and conservatories a few species of land 

 Mollusca have been found which have accidentally been brought 

 to the United States, usually with plants. In some instances 

 these imported species have spread beyond the confines of green- 

 houses and may be found in yards, cellars and other places in 

 cities. 



For the sake of completeness, and because many of the 

 imported species are sure to be found at one time or another 

 by students of Illinois land Mollusca, they are described and 

 figured in this fieldbook. 



Both snails and slugs are numbered among the introduced 

 species. Of the snails with shells the following species have 

 been recorded: Oxychilus cellarium, Oxychilus lucidum and 

 Opens mauritianum. Of introduced slugs Limax maximus, 

 Liniax fiavus and Testacella europaea have been recorded. 



Species of foreign slugs other than those reported will prob- 

 ably be found in Illinois. A common European species, Avion 

 circiimscriptiis Johnston, has recently been reported by A. La 

 Rocque from several places in Canada, notably in Nova Scotia 

 and in Quebec and Ontario, near Ottawa and Toronto. Some 

 years ago it w^as recorded from near Niagara Falls, and there 

 is no reason why it might not be found in the northern part of 

 the United States. A careful examination of the greenhouses in 

 public parks might bring to light a number of species, not only 

 of slugs but of snails, introduced on imported plants. 



OXYCHILUS CELLARIUM (Muller) 



The shell of the European snail Oxychilus cellarium is less 

 than one-half inch (11-12 mm.) in diameter; its height is about 

 half this measurement. It is yellow in color and shining in 

 texture, has a flattened spire showing usually 4 whorls and a 

 rather wide umbilicus. The base is circular and almost flat. The 

 aperture when viewed from the front is obliquely ovate. 



The animal of this species is black or blue-black in color 



1139] 



