238 HELICID^E. 



abundantly under fragments of wood, in damp places 

 near the water's edge, in company with Helix chersina 

 and Pupa modesta" 



On its upper surface, it appears to be identical with 

 Helix indentata ; while on the base, its resemblance to 

 Helix arborea is striking. It appears to be a widely 

 diffused, and very common species. It is often found in 

 company with H. arborea. 



67. HELIX OTTONIS, PFEIFFER. 



PLATE XXIX. a. FIGURE 3. 



H. testa depressa, pallide cornea, pellucida, umbilicata, 

 basi sub-plana ; anfractibus quatuor convexiusculis, striatis ; 

 labro tenui, acuto ; apertura sublunari. 



SYNONYMS AND EEFEEENCES. 



Helix Ottonis, PFEIFFER, Wiegmann's Archiv. 1840, I. 251. 

 Helix arborea, (variety) PFEIFFER, Monog. Helic. Viv. II. 95. 



DESCRIPTION. 



SHELL small, depressed, orbicular, but not remarkably 

 transparent, of a watery horn-color, becoming opaque 

 when dead, very faintly marked by the lines of growth. 

 Spire of about four slightly convex whorls, the outer one 

 obscurely angular at periphery ; suture very delicate ; 

 beneath convex, with a small, well denned umbilicus. 

 Aperture crescentic, lip simple. 



Diameter one-fifth of an inch ; axis one-tenth of an 

 inch, 



