228 



A MANUAL OF AMERICAN LAND SHELLS. 



A species of the Cumberland Subregion 

 and North Carolina. 



mountains of Tennessee 



Fig. 250. 



Zonites sii^nificans, Bland. 



Shell umbilicate, depressed, discoidal, thin, with fine, irregular striae, 

 which are almost obsolete at the base, shining, pale horn-colored; 

 spire little elevated ; suture slightly impressed ; whorls 6, 

 subplanulate, the last roundly inflated, rather flat at the 

 base, excavated around the umbilicus, which is pervious 

 and equal almost to one-fifth of the diameter of the shell ; 

 aperture oblique, depressed, lunate, furnished within with 

 several rows of upright denticles on the floor of the whorl; 

 peristome simple, acute. Greater diameter 4^, lesser 4"""; 



Z. significant, hgjp'ljt 2""". 



Helix significans, Bland, Am. Journ. Concb., li, No. 4, 372, pi. xxi, fig. 9 (1866). 

 Gastrodonia significans, Tryon, Am. Journ. Couch., ii, 163 (1866). 

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

 Zonites significans, W. G. Binnky, Terr. Moll., v, 132, excl. fig. 



Fort Gibson, Ind. T. ; Union County, Tennessee. I consider it a 

 species of the Cumberland Subregion, with the western range shared 

 by many of the species of the subregion. 



In a young specimen of significaris, having 4 whorls only, there 

 are 3 small teeth, 1 by itself and at some distance from it 2 others, 

 situated as the teeth are in mnltidentatm. Whether these teeth are 

 or not constant in the antepenultimate whorl of significans^ I am una- 

 ble to determine. It is especially allied to Z. multidentatus, from which 

 it difiers in being of larger size, with wider umbilicus. (Bland.) 



Jaw not observed. 



Lingual membrane (Terr. Moll., V, Plate III, Fig. E) 16-1-6 teeth, 

 with 2 perfect laterals. 



Genitalia not observed. 



Zonites Andrewsi, W. G. Binnky. 



Compared with Z. lasmodon, this species has fully 8 whorls, is 6^"'" 

 Fig. 251. in diameter, the umbilicus 1""" wide, while lasmodon has 7 

 whorls, is 7""" wide, and has an umbilicus 2™'" wide. This 

 shell has also five parallel laminae, while lasmodon has only 

 two, or at most three, and does not show the successive 

 rows of lamella} which are characteristic of Andrewsi, radi- 

 ating from the center. 

 z. Andrewsi. From Z. significans it differs in its larger size, greater 



