HELIX. 



125 



Fig. 208. 



especially behind the aperture, more distinctly defined. Greater 

 diam. 22, lesser 19i; height 8^ mill. (5 whirls). Kentucky and 

 Tennessee. 



Yar. y. — Whirls planulate above, and so e.xserted as to show 

 the carinated edges of all excepting the apicial whirls, the last 

 whirl with an acute projecting carina continued 

 to the back of the aperture ; the umbilicus not 

 always entirely covered by the reflected lip. 

 Greater diam. 2H, lesser 18^; height T mill. 

 (5 whirls). Tennessee. 



A curious form of the species is figured here, 

 in which the peristome is carried around the 

 umbilicus, instead of over it. 



The lingual membrane has 115 rows of 

 34 — 1 — 34 rows each ; central teeth 

 long, conical, with a pointed apex ; 

 laterals bicuspid, the inner cusp of 

 same shape as the central teeth ; 

 uncini stout, irregularly denticulated. 



Lingual dentition of Helix palUnta. 



Helix palliata. 



Fig. 209, 



Fici. 210. 



Helix obstricta, Say. — Shell with the umbilicus closed, depressed, 

 with heavy, rib-like strise, and interstitial, minute, revolving lines, reddish 

 horn-color ; spire flattened ; whirls five, depressed, the last convex below, 

 with a prominent, acute carina above ; aperture 

 oblique, subtriangular, narrowed by a tongue-shaped, 

 arcuately-entering tooth on the parietal wall ; peri- 

 stome thin, broadly expanded, its inner edge with a 

 heavy thickening of white callus, its right portion 

 with a stout erect denticle, its basal portion straight, 

 dilated, reflected, with a long, lamellar, less prominent 

 denticle. Greater diam. 26, lesser 22; height 11 mill. 



Helix obstricta, Say, Jonrn. Phila. Acad. II, 154 (1821) ; Binxey's ed. 17. 



— Pfeiffer, Mon Hel. Viv. 1, 317.— Reeve, Con. Icon. no. 683 (1852). 



— W. G. Binney, Terr. Moll. IV, 57.— Bland, Ann. N. Y. Lye. VII, 



446. 

 Helix palliata, var. a. Say, Journ. Phila. Acad. II, 152 ; Binney's ed. 16. 



Helix obstricta. 



