334 PROCEEDINGS OF THE ACADEMY OE 



DESCRIPTIONS OF NEW SPECIES OF AMERICAN LAND AND FRESH- 

 WATER SHELLS. 



BY JAMES LEWIS, M.D. 



In ray paper on the Land Shells of East Tennessee, published 

 in the Amer. Journ. Conch, vi., 188, may he found some remarks 

 upon certain shells treated on page 191 as a large variety of Helix 

 Sayii. The shells upon which the remarks here referred to were 

 based, were mutilated specimens, in which some of the charac- 

 teristics of the species they represented were not clearly attested. 

 Since the publication of the above-mentioned paper additional 

 specimens have been secured, which leave nothing to be inferred 

 as to the true character of the species which is now unhesitatingly 

 presented as new. 



Mesodon [Helix] Chilhoweensis, Lewis. 



Shell of large size, umbilicated, convex-depressed ; epidermis, 

 pale russet, scarcely paler below; whorls six to seven with numer- 

 ous and somewhat coarse stria? ; suture well impressed; peristome 

 white, well developed and widely reflected, with a, faint rudimen- 

 tary tooth indicated near the umbilical region ; parietal wall with- 

 out any indication of a tooth; in other particulars the shell may 

 be compared with the species hitherto known as Helix Sayii. 



Chilhowee Mountain, East Tennessee, 1869. 



Tusquita Bald Mountain (6600 feet elevation), East Tennessee. 

 1873. 



The following are the dimensions of two specimens from the 

 last-named station. 



1st. Greatest diameter 1.65 inches = 42 mm. Least diameter 

 1.32 inches = 33.8 mm. Elevation (parallel to axis) 1.03 inches 

 = 26.3. 



2d. Greatest diameter 1.57 inches = 49.9 mm. Least diameter 

 1.28 inches = 32.7. Elevation 0.94 inches = 23.8 mm. [See 

 Plate 12, figures 5, 6, 7, Amer. Journ. Conch, vi.] 



Remarks. This species will be found uniformly to differ from 

 H. Sayii (a large variety of which it was supposed to be), by 

 having one more lohorl, a more broadly reflected lip, the extremely 

 rudimentary character of the tooth when present on the lip, and 

 by the entire suppression of the parietal tooth, without reference 

 to the larger size of the shell. The species seems to be confined 



