HELIX. 



237 



SHELL small, depressed, thin, fragile ; epidermis pale, 

 or brownish horn-color, wrinkled, shining ; whorls four, 

 the last rapidly enlarging towards the mouth ; aperture 

 rounded ; lip simple, its edge rather thickened, not 

 acute ; umbilicus small, but well marked and constant. 



Greatest transverse diameter more than one-eighth of 

 an inch. 



GEOGRAPHICAL DISTRIBUTION. Inhabits Vermont, 

 Ohio, Missouri, and Massachusetts, and is a widely 

 spread species. Found on the shores of Fresh Pond, 

 near Boston. 



REMARKS. For the following remarks I am indebted 

 to Dr. Gould. " In size, the depressed-conical shape of 

 the upper surface, the number of whorls, and the rapid 

 enlargement of the largest whorl, this shell corresponds 

 with Helix indentata. It differs in its darker, smoky 

 horn-color, its constant umbilicus, its rather thick and 

 shining lip, and in its whitish wrinkles, which, instead of 

 being remote, are crowded. From Helix arbor ea it 

 differs in having one whorl less, the last one rapidly 

 dilating, its apex not being depressed, its thinner struc- 

 ture and more glossy surface, and in its somewhat 

 smaller umbilicus. In Helix arborea the lip has a 

 flexuous curve, but is nearly a direct section of the whorl 

 in this. Though all of the same size and general appear- 

 ance, the three may be readily separated when mingled. 

 Indeed, its claims as a distinct species are not very 

 obvious without viewing the three together. It is found 



