Notice of Land and Freshwater Shells. 365 



Helix polygyrella, now sp. 



T. late umbilicata, discoidea, pl;imilata,Tiitida, transliicida, Inteo-cornetk, 

 superne costiilat^, costis ad aperturam obsoletis, basi la3vinsciila, spira 

 vix elevata ; aiifr. T-S convexiusculis, lonte accrescentibus, ultimo antice 

 brevitcr deflexo, ititus fieriebus dnobus reinotis triiim dentium iminito; 

 umbilico ad apicem pervio ; apeitnia subverticali, obliqua, lunato-ovali ; 

 pcrist. superne dopresso, albo, simplici, valde iucrassato, inarj^inibus dente 

 pliciforini, elevato, albo, triangular! junctis. 



Shell widely umbilicate, discoidal, flat, sinning, translucent, 

 yellowish liorn colored, ribbed above, the ribs obsolete near the 

 aperture, base rather smooth ; spire scarcely elevated ; whorls 

 7-8, somewhat convex, gradually increasing, the last slightly 

 deflexed above, armed within with two rows of three teeth, 

 seen through the outer wall; imibilicus pervious, of equal size 

 to the apex; aperture subvertical, oblique, lunate-oval; peri- 

 stome depressed above, white, simple, much thickened within, 

 the margins joined by a white pliciform elevated triangular 

 tooth, 



Diam. maj. 11^-, rain. IO5, Alt, 5 mill. 



Station. — Inhabits moss and decaying wood in the dampest 

 parts of the spruce forests. 



Habitat. — Common on the Coeur d'Alene Mountains, espe- 

 cially on their eastern slope. J. G. Cooper ! 



jRemarks. — This very interesting species is unlike any shell, 

 with which we are acquainted, hitherto found on the North 

 American Continent. Although entirely distinct from the 

 Brazilian II. folijgyrata Born it has some affinity with it, espe- 

 cially as regards the form generally, and the presence of the 

 internal teeth. Il.jpolygyrata has five teeth within the last whorl, 

 three on the under surface of the outer wall, and two opposite to 

 the others on the exterior of the penultimate whoil. Our species 

 has two distinct rows of three teeth, all the teeth beino^ on the 



