HAPLOTREMATIDAE 



91 



Family HAPLOTREMATIDAE 



Shells of the family Haplotrematidae resemble those of some 

 of the Zonitidae, but they are much flatter and more discoidal, 

 and they have a wider umbilicus than is to be found in any of 

 the large species of the latter family. 



The animal has a long, narrow body and long, slender eye 

 peduncles. The upper surface of the body is gray, and the 



tentacles and eye peduncles are bluish. The mantle collar at 

 the edge of the shell is reddish orange. The same color tinges 

 the posterior part of the animal. The base of the foot is dusky 

 white. The shell is carried near the posterior extremity of the 

 body. It is but slightly tilted to one side and stands almost 

 vertical when the animal is in motion. 



In habits the animal is carnivorous, its long, slender body 

 enabling it to crawl within the shell of its hapless victims, which 

 in many cases are the larger snails, Polygyra, Anguispira or 

 Mesomphix. The teeth on the lingual ribbon or radula are 

 fanglike, indicating carnivorous habits (see page 7). 



Genus HAPLOTREMA Ancey 



The family Haplotrematidae contains but one genus, Hap- 

 lotrema, but nearly a dozen subgenera and sections have been 

 proposed. The family is purely American. The majority of 

 species live in the United States, although a few inhabit northern 

 South America, Mexico, Cuba, Porto Rico and other West 

 Indian islands. 



The only Illinois species, Haplotrema concavum, shown in 

 the figure, is known from Quebec, Canada, west to Minnesota 

 and southward to Alabama and Arkansas. This is the only 

 species found in the United States east of the Rocky Mountains. 



