EASTERN PROVINCE INTERIOR REGION SPECIES. 213 



Jaw as usual in the genus. 



Z. dcmissus (Terr. Moll., V, Plate II, Fig. O) has 45-1-45 teeth, with 

 15 laterals. My specimen was one of the large East fig. 224. 

 Tennessee form, called Z. acerrus by Dr. Lewis (Proc. 

 Ac. N. Sc. Phila., 1872, 110). The typical form, from 

 near Mobile, has, however, a perfectly similar dentition. 



The genitalia are like those of Z. intcrtcxti(s, Binney, ^- acerms. 

 figured by Dr. Leidy in Terr. Moll., I. The accessory glands of the 

 dart sac are rather shorter in demisum. 



The large form referred to as Z. acerrus nbove is here figured. Its 

 greater diameter is 20™"; height, S""". It has over 7 whorls. From 

 mountains of Eastern Tennessee and North Carolina. (Fig. 224.) 



Zonites lig^erus, Say. 



Shell perforated, orbicularly convex ; epidermis yellowish horn-color, 

 shining; whorls 7, finely and thickly striated transversely, fig. 225. 

 smooth below; suture not much impressed; aperture semi- ,/^ 

 lunate, rounded ; peristome thin, acute ; base and side of 

 the outer whorl, within the aperture, thickened and white ; 

 perforation very small ; umbilical region impressed. Greater ^- Hgerus. 

 diameter 15, lesser IS""" ; height, 10"'"'. 



Helix ligera, Say, Journ. Acad., ii, 157(1821); Binney's ed., 19.— Binney, Bost. 

 Jonru. Nat. Hist., iii, 412, pi. xx, fig. 1 (1840); Terr. Moll., ii, 204, pi. xxxv 

 (1851).— Leidy, T. M. U. S., i, 257, pi. xii, figs. 4-7 (1851), anat.—DE Kay, 

 N. Y. Moll., 40, excl. fig. ? (1843).— Chemnitz, ed. 2, i, 108, pi. xxxiii, figs. 

 5-7.— Desha YES, in Fer., i, 184.— Pfeiffer, Mon. Hel. Viv., i, 48. — Reeve, 

 Con. Icon., 493 (1852).— W. G. Binney, Terr. Moll., iv, 95 .—Lewis, Am. 

 Journ. Conch., vi, 190, pi. xii, figs. 3, 4. 



ReUx Fafiiiesquea, Fi^russac, Tab. Syst., 50; Hist., pi. Ii, a, fig. 5; pi. 1, a, figs. 4, 5? 

 — Pfkiffer, Symb., i, 39. 



Helix Wardiana, Lea, Trans. Am. Phil., vi, 67, pi. xxiii, fig. 82; Obs., ii, 67 (1839). — 

 Troschel, Arch, fiir Nat., 1839, ii, 221.— De Kay, N. Y. Moll., 46. 



Mesompliix ligeraTRYCm, Am. Journ. Conch., ii, 255 (1866). 



Hyalina ligera, W. G. Binney, L. & Fr.-W. Sh., i, 44 (1869). 



Zonites Ugerus, W. G. Binney, Terr. Moll., v, 105. 



A species of the Interior Kegion, having been found from Arkansas 

 and Georgia to the Great Lakes ; north of Maryland it does not appear 

 east of the Appalachian chain. It is also found fossil in the Post-Plio- 

 cene of the Mississii^pi Valley. 



Animal uniform blackish slate-color over the whole upper surface, 



