26 CONCHOLOGIA CESTRICA. 
Sub-genus MESODON, Rarinesour, 1831. 
Animal of Mesodon albolabris.—(B. & B.] 
Fig, 14, 



Shell sub- globose, or orbiculate-depressed ; umbilicus 
open, or covered; thin, finely striate, or decussate, 
sculptured; whorls 5 or 6, regular, aperture rounded, 
or lunate, sometimes with a parietal tooth; peristome 
broadly reflected, white, margin rarely unidentate. 
M. albolabris, Say. 
Helix albolabris, Say, Nich. Encyc., Amer. Ed., 1817. 
M. albolabris. —(B. & B.| Jaw of M, albolabris. — | Morse. } 

Shell large, convex, yellowish- brown, or russet; 
whorls 5 or 6, obliquely, .fine-striate, with still finer 
revolving stria, most distinct behind the reflected lip; 
lip broadly reflected, and flattened, closing the umbilicus 
when mature ; lingual membrane of 123 rows, of 44-1-44 
teeth; buccal plate heavy, arcuate, with ten large ribs, 
crenulating the margins of the plate. H.15, W. 25, mil- 
limeters. Varies much in size. 
Station, rocky woodlands, Chester County, frequent. 
