HELIX. 235 



65. HELIX ARBOREA, SAT. 



Plate XXIX. Figuee 3. 



H. testa parva, orbiculato-depressa, tenui, pellucida, nit- 

 ida, umbilicata ; apertura kub-rotundata ; labro simplici, 

 acuto. 



SYNONYMS AND R£Fi:B£NCES. 



Helix arhorea, Say, Nich. Encyc. IV. pi. 4, f. 4. 

 KiRTLAND, Ohio Report, 172. 

 Sager, Michigan Catalogue, 14. 



BiNNEY, Boston Journ. Nat. Hist. III. 422, pi. 22, f. 1. 

 De Kay, Nat. Hist. New York, 30, pi. 2, f. 19. 

 Gould, Invertebrata, 1S2, f. 110. 



Ad.ams, Vermont Mollusca, 10 ; Sillim. Journ. XL. 273. 

 Wheatley, Catal. of Shells, p. 19. 

 Pfeiffer, Monog. Helic. Viv. I. 95. 

 Chemnitz, 2d ed. tab. 85, f. 33-35. 



DESCRIPTION. 



Animal. Head, neck, and tentaculse blackish, or 

 indigo blue, upper parts bluish, posterior parts whitish, 

 transparent, sometimes wholly white. Foot thin and 

 narrow. 



Shell depressed, very slightly convex, thin, pellucid ; 

 epidennis amber-colored, smooth, shining ; whorls four to 

 five, with very minute, oblique striae, apparent when 

 viewed with a microscope ; aperture somewhat rounded ; 

 lip thin, acute ; umbilical region indented ; umbilicus 

 moderate, well developed, round, and deep. 



Transverse diameter commonly about one-sixth of an 

 inch, sometimes attains one-fourth of an inch. 



