320 TERRESTRIAL AIR-BREATHING MOLLUSKS. 



the outer whorl is a little angular at its periphery ; beneath, it is more smooth, 

 moderately convex, with the central region excavated, and covered with a glaz- 

 ing of white callus ; the aperture is lunate, and very oblique ; the peristome is 

 white, broadly reflected, its basal portion horizontal, and its outer portion flex- 

 uous. Greater diameter 20, lesser 15 mill. ; height, 8 mill. 



Helix dejecta, Gould, Terr. Moll., II. 91. Not preocc. in mesodon. 



Helix ahjeda, Gould, Proc. Bost. Soc. Nat. HLst., III. 40 (Oct., 1848); Terr. 



Moll., II. 122, PI. XIII. a. Fig. 2. — Pfeiffer, Mon. Hel. Viv., III. 270. 

 Helix divesta, Gould, Terr. Moll., II. 357. —W. G. Binney, Terr. Moll., IV. 



51 ; L. & Fr.-W. Sh., I. 138 (1869). — Pfeiffer, Mon. Hel. Viv., IV. 322. 

 Mcsodcni divesta, Tryon, Am. Jouni. Conch., III. 45 (1867). 



Washita Springs, Arkansas ; Vernon County, Mississippi. It may prove to 

 be a species of the Texan Subregion. 



Jaw with 10 ribs. 



Lingual membrane (PI. XVI. Fig. V) as in alholabris: teeth 46—1 — 46, 

 with 16 laterals. 



The genitalia are as usual in the genus : the penis sac is very long, cylin- 

 drical, stout, tapering at the top ; the vas deferens enters at its apex ; the 

 retractor muscle is attached to the vas deferens ; the genital bladder is short, 

 oval, stout, on a short, stout duct. 



Mesodon multilineata, Say. 



Vol. in. PI. III. 



Shell imperforate, depressed-subglobose ; spire convex, rather thin ; epider- 

 mis yellowish brown, or russet-color, with numerous reddish-brown, finely undu- 

 lated, revolving lines and bands; whorls between 5 and 6, convex, with delicate, 

 parallel, oblique striae, the last ventricose ; suture distinctly marked ; aperture 

 lunate, slightly contracted by the peristome ; peristome white, not much ex- 

 panded, reflected, rather thin ; umbilical region impressed. Greater diameter 

 23, lesser 20 mill. ; height, 14 mill. 



Helix multilineata, Say, Journ. Acad. Phila., II. 150 (1821) ; ed. Binney, 15. — 

 F^RUSSAC, Hist., PI. XLVI. a. Fig. 3. — Binney, Bost. Journ. Nat. Hist., I. 

 480, PI. XIV. (1837). —Terr. Moll., II. 103, PI. III.— Leidy, Terr. MoU. U. 

 S., I. 254, PI. VIII. Figs. 1-6(1851), anat. — DeKay, N. Y. Moll., 41, PI. 

 III. Fig. 34 (1843). — Pfeiffer, Symb. ad Hist. Hel., I. 41 ; Mon. Hel. Viv., 

 I. 290 ; in Chemnitz, ed. 2, II. 41, PL LXXI. Figs. 17-19 (1849). —Reeve, 

 Con. Icon., No. 691 (1852). — Deshayes in F^ii., I. 113. —W. G. Binney, 

 Terr. Moll., IV. 



Mesodon rMiltilineata, Tryon, Am. Journ. Conch., III. 45 (1867). 



In the States bordering on the Ohio River, from New York to Minnesota. 

 It is a species of the Interior Region. 



Animal blackish, granulated ; granules wliitish with darker interstices ; foot, 

 beneath, black. 



