EASTERN PROVINCE INTERIOR REGION SPECIES. 215 



Helix interiexta, Binney, Bost. Journ. Nat. Hist., iii, 413, pi. xx, fig. 2 (1840) ; Terr. 

 . Moll., ii, 206, pi. xxxvi. — Philippi, Icon., ii, 9, .5, pi. vi, fig. 16.— Chem- 

 nitz, ed. 2, i, 208, pi. xxxiii, figs. 8-10.— Pfeiffer, Mod. Hel. Viv., i, 49. — 

 Reeve, Con. Icon., 668 (1852).— Leidy, T. M. U. S., i, 257, pi. xii, figs. 1-3 

 (1H51), anat.— De Kay, N, Y. Moll., 38, pi. iii, fig. 29 (1843).— W. G. Binney, 

 T. M., iv, 96. 



Mesomphix intertexta, Tryon, Am. Jonrn. Conch., ii, 254 (1866). 



TlyaUna intertexta, W. G. Binney, L. &. Fr.-W. Sh., i, 44 (1869). 



Zoniies intertextus, W. G. Binney, Terr. Moll., v, 107. 



A Post-Pliocene species, now found over the whole Interior Eegion. 

 The extreme points to which I have traced it are New York to Indiana, 

 Tennessee to Georgia, and Texas. 



® ' Fifi. 227. 



Animal resembling outwardly that of Z. Ugerus. It has 

 all the generic characters of Zonites. 



The specimen figured above is unusually large. There is a z. huertex- 

 smaller, strongly carinated variety, with a short, conical enlarged. 

 spire, which I here figure. 



The shell resembles some varieties of Z. Ugerus so nearly that Dr. 

 Binney hesitated some time before he considered it distinct. The spire 

 is less high in a shell of the same size, has a smaller number of whorls, 

 and is more pyramidal in shape than in that species. The diameter in 

 full-grown specimens is greater and the base is flatter. The epider- 

 mis is darker and less shining, the shell is thicker and less pellucid, 

 the deposit of testaceous matter within the aperture is less. The size 

 of the umbilicus and the shape of the aperture are the same in both. 

 But the principal distinction consists in the spiral lines which revolve 

 on the whorl, intersecting the stria? of growth, but so minute as hardly 

 to be perceptible to the naked eye, yet present in every specimen which 

 I have examined. The whitish, narrow band, shaded below with rufous, 

 apparent on the outer and sometimes on the second whorl, generally 

 aids in identifying it, though it is sometimes wanting. Young speci- 

 mens are much more depressed than those of Z. Ugerus, and are some- 

 times distinctly carinated. The depression of the umbilical region is 

 not so evident in this as in the preceding species. The rufous band 

 below the white band is well defined and broad in a single specimen 

 before me. Nearly allied as it is by its shell to Ugerus, it differs in a 

 marked manner in its genitalia (see Leidy's figure in Terr. Moll., I, 

 Plate XII, Fig. 1) by having a second accessory pyriform gland to the 

 dart sac (8, 8). It may also be distinguished from Ugerus by the greater 

 number of the marginal teeth on its lingual membrane. 



