HELIX. 



81 



Fig. 141. 



This is a northern species, being found through British America, 

 at Great Slave Lake, &c., Canada, New England, and extends to 

 Yirginia and Kansas. Also on the Pacific side of the Rocky 

 Mountains — Hell-Gate River. 



Jaw arcuate, ends attenuated; anterior 

 surface with converging striae ; concave 

 margin irregularly notched, no median 

 projection. 



Lingual membrane with 100 rows of 

 16 — 1 — 16 teeth; centrals tricuspid, the side cusps very small; 



Ja.\7 of Helia; striatella. [Mokse] 



Fig. 142. 



Lingual dentition of Helix striatella. [Mokse.] 



laterals of same shape, but bicuspid ; laterals short, broad, 

 bidentate. 



Helix hornii, Gabb, Am. .Journ. Conch. II, 330, pi. xxi, f. 



5 (]S(J(!). 

 Eyalina hornii, Tryo\, Am. Joiirn. Conch. Ill, 1G3, pi. 



xi, f. 36-38 (1867). 

 6 July, 1868. 



Fig. 143. 



Helix IlornSi, Gabb. — Shell umbilicated, globosely depressed, thin, 

 coarse, reildish horn-color, under the epidermis obliqnely striate, hirsute; 

 whirls four, scarcely convex, the last inflated below ; um- 

 bilicus pervious, showing the whirls to the apex ; aperture 

 oblique, subcircular; peristome simple, acute, its ends 

 hardly approaching, that of the columella not widened, 

 nor reflected. Greater diam. 4, lesser 3^ ; height 1 mill. 



Helix hornii. 



