MESODON. 



335 



Mesodon Downieana, Bland. 



Shell umbilicate, umbilicus nearly covered, subglobose, thin, subpellucid, 

 •with obsolete rib-like striae, decussated with crowded microscopic spiral lines, 

 greenish horn-colored ; spire short, obtuse ; whorls 5, convex, the 

 last tumid, anteriorly somewhat gibbous, scarcely descending, 

 constricted ; aperture oblique, lunate oval ; peristome white, labi- 

 ate, reflected, right margin expanded, columellar margin angu- 

 larly dilated, nearly covering the umbilicus. Greater diameter 

 10£, lesser 9| mill. ; height, 6 mill. 



Fig. 217. 



Helix Doitmieana, Bi.and, Ann. N. Y. Lye, VII. 420, PI. IV. Figs. 

 23, 24 (1861). — W. G. BlNNEY, L. & Fr.-W. Sh., I. 151 (1869). 

 Mesodon Doivnieana, Tryon, Am. Journ. Conch., III. 47 (1867). 



M. Doivnieana. 



Fig. 218. 



Munroe County ; University Place, Franklin County ; Tennessee, Whitley 

 County, Kentucky. A species of the Cumberland Subregion. 



Animal with the usual characters of the genus. 



Jaw as usual ; over 1 ribs. 



The lingual membrane (PI. VIII. Fig. F) has 35—1—35 teeth, with 12 

 laterals. The side cusps and cutting points are visible on the second lateral 

 tooth. 



Mesodon Lawi, Lewis. 



Shell narrowly umbilicated, globose, surface hardly broken by delicate in- 

 cremental striae, horn-colored ; spire elevated, apex obtuse . 

 whorls 4, convex, suture impressed, the last globose, descending, 

 deeply constricted behind the peristome ; aperture oblique, lu- 

 nate, narrow, with a linguiform tooth on tJie parietal wall ; peri- 

 stome white, thickened, reflected, its terminations approached 

 slightly, that of the columellar somewhat concealing the very 

 narrow umbilicus. Greater diameter 6, lesser 5 mill. ; height, 3 

 mill. 



M. Lawi. Helix Lawi, Lewis, Proc. Acad. Nat. Sci. Philad., 1874, 118 



(Fig.). 

 Probably a species of the Cumberland Subregion. Thus far only found at 

 Hayesvillu, Clay County, North Carolina, in a field, at the roots of Strawberry 

 plants, by Miss Annie M. Law. 

 Animal unobserved. 



Mesodon jejuna, Say. 



Vol. III. PI. XLIL Fig. 2. 



Shell umbilicated, subglobose ; epidermis corneous, nearly smooth ; spire 

 rather prominent ; suture impressed; whorls rather more than 5, the last am- 

 ple ; striae of increase hardly visible ; peristome white, very narrow, reflected, 



