HELIX. 211 



REMARKS. In form, it may be compared, among the 

 shells of this continent, to //. concava and II. alternata ; 

 but, in its opaque and rugged aspect, and most of its 

 characters, it nearly resembles //. alpina and its varie- 

 ties, of Europe ; but that species is more elevated, has a 

 smaller umbilicus, the lip rcflexed, and no revolving 

 bands. [G.] 



52. HELIX SPORTELLA, GOULD. 

 PLATE XXII. a. 



H. testa planulata, fragili, nitida, luteo-cornea, subtus con- 

 cava, late umbilicata, lineis increment! conspicuis, et lineis 

 volventibus subtilissimis confertis decussata ; spira anfract- 

 ibus quinis, ultimo magno ; sutura profunda ; apertura 

 rotundata, infra subangulata ; labro acuto, simplici. 



SYNONYMS AND REFERENCES. 



Helix sportella, GOULD, Proc. Bost. Soc. Nat. Hist. II. 167, Aug. 1S4G. 



Expedition Shells, 18. 

 PFEIFFER, Mouog. Helic. Viv. I. 111. 



DESCRIPTION. 



SHELL much depressed, convex above, concave be- 

 neath, sloping into a broad, tunnel-shaped umbilicus. 

 Surface delicate and shining, of a pale, yellowish-green 

 color, regularly sculptured with sharp, coarse lines of 

 growth, which are crossed by fine, crowded, revolving 

 lines, which cut merely the summits of the radiating 

 ridges, so that, to the naked eye, the surface appears 

 minutely granulated ; but under a magnifier the raised 



