ZONITES. 105 



ern Pennsylvania, Xorth Carolina (at least as far as Goldsboro'), Georgia, Ala- 

 bama to the Gulf of Mexico, and Arkansas. 



Animal light slate or smoky white, dark blue on head, eye-peduncles, and 

 tentacles ; tuberosities on back few and large; a line of furrows runs along the 

 side of the foot, and rising on the tail meets that of the opposite side above a 

 well-marked mucus pore. The sides, labia-like, of the pore are prominent and 

 swollen. The pore opens and shuts, and freely exudes mucus. 



Jaw as usual in the genus. 



Z. demissus (PI. II. Fig. O) has 45 — 1 — 45 teeth, with 15 laterals. My spe- 

 cimen was one of the large East 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 den- 

 tition. 



The genitalia are like those of Z. interlextus, Binney, fig- 

 ured by Dr. Leidy in Vol. I. The accessory glands of the 

 dart sac are rather shorter in demissus. 



The large form referred to as Z. acerrus above, is here 

 figured. Its greater diameter is 20 mill.; height, 8 mill. It has over 7 

 whorls. From Eastern Tennessee. 



Zonites ligerus, Say. 



Vol. III. PL XXXV. 



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

 ing ; whorls 7, finely and thickly striated transversely, smooth below ; suture 

 not much impressed ; aperture semilunate, rounded ; peristome thin, acute ; 

 base and side of the outer whorl, within the aperture, thickened and white ; 

 perforation very small; umbilical region impressed. Greater diameter 15, 

 lesser 13 mill.; height, 10 mill. 



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

 Bost. Journ. Nat. Hist., III. 412, PI. XX. Fig. 1 (1840); Terr. Moll., II. 204, 

 PI. XXXV. (1851). —Leidy, T. M. IT. S., I. 257, PL XII. Figs. 4-7 (1851), 

 anat. — DeKay, N. Y. Moll. 40, excl. fig.? (1843). —Chemnitz, 2d ed., I. 

 108, PL XXXIII. Figs. 5-7. — Deshayes in Fer., I. 184. — Pfeiffer, Mon. 

 Hel. Viv., I. 48. — Peeve, Con. Icon., 493 (1852). — W. G. Binney, Terr. 

 Moll., IV. 95. —Lewis, Am. Journ. Conch., VI. 190, PL XII. Figs. 3, 4. 



Helix Rafinesquea, Ferussac, Tah. Syst., 50 ; Hist., PL LI. a, Fig. 5 ; PL L. a, 

 Figs. 4, 5?— Pfeiffer, Symb., I. 39. 



Helix Wardiana, Lea, Trans. Am. Phil., VI. 67, PL XXIII. Fig. 82 ; Obs., II. 67 

 (1839).— Troschel, Arch, fur Nat. 1839, II. 221.— DeKay, N. Y. Moll., 46. 



Mesomphix ligera, Tryon, Am. Journ. Conch., II. 255 (1866). 



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



A species of the Interior Region, having been found from Arkansas and 

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



