HELIX. 031 



SHELL very much depressed, thin, fragile, pellucid ; 

 epidermis light greenish horn-color, smooth, highly pol- 

 ished ; whorls five, slightly rounded, with minute and 

 almost imperceptible, oblique strise ; aperture not dilated, 

 its transverse diameter the greatest ; umbilicus moder- 

 ate, regularly rounded, deep ; base rounded, thickened 

 within by a testaceous deposit, bluish-white ; lip simple, 

 acute. 



Greatest transverse diameter less than half an inch. 



GEOGRAPHICAL DISTRIBUTION. Inhabits the North- 

 eastern and Middle States, in gardens ; is common in 

 the city of Boston, in damp cellars. 



REMARKS. This is the shell which was found by Mr. 

 Say, in gardens in the city of Philadelphia, and by him 

 described as Helix glaphyra. Its restricted habitat in 

 cellars and gardens in the immediate vicinity of maritime 

 cities, long since induced me to suppose it might be an 

 imported species ; and an opportunity of examining a 

 considerable number of specimens of Helix cettaria, 

 Miiller, brought from England, enables me to say, that 

 it is absolutely identical with that species. Shells of 

 the same size and growth from the European and Ameri- 

 can localities cannot be distinguished from each other. 

 Its introduction is easily accounted for, when we consider 

 its habits. It has been found also in New Holland, and 

 many parts of the world remote from each other, where 

 it was doubtless conveyed on water casks, and packages 

 usually stored in cellars. 



