HELLX. 



131 



It varies considerably in appearance. Some individ- 

 uals never reacli half the standard size of the species. 

 It is more or less globose, has the umbilicus sometimes 

 covered, and at other times is destitute of the tooth. 

 The animal, though usually yellowish, I have noticed to 

 be in a few cases blackish. II is probable that the color 

 of the animals of this genus is much influenced by the 

 nature of their food. 



Lister's figure, Sjmopsis Conch, etc. t. 91, f. 91, is 

 probably intended to represent this species. 



17. HELIX EXOLETA, BiNNEY. 

 Plate X. 



H. testa orbiculato-ventricosa, imperforata, luteo-cornea ; 

 anfractibus transverse striatis ; striis confertis, obliquis ; 

 appendiculo dentiformi, albo, columellee oblique adnato ; 

 peristomate albo, margine reflexo. 



SYNONYMS AND HEFERENCES. 



Helix zaleta, Binney, Boston Journ. Nat. Hist. I. 49S, pi. SO. 



KiKTLAND, Ohio Reiiort, 173. 



Sager, Michigan Catalogue, 14. 



De ICay, New York Report, 31. 

 Helix albolabris, var. Fekussac, Hist. pi. 46, a. f. 6. 



