4 J^otice of Land and Freshwater Shells. 



Helix polygyrella, nov. sp. 



T. late umbilicata, discoidea, planulata,Tiitida, translucida, luteo-corne^, 

 superne costulata, costis ad apertiiram obsoletis, basi lajviiisciila, spira 

 vix elevata ; anfr. 1-S convexiiisculis, lente accrescentibus, ultimo antice 

 breviter deflexo, intus seriebus duobns remotis trium deiitium munito; 

 umbilico ad apicern pervio ; apertnra subverticali, obliqua, lunato-ovali ; 

 perist. superne depresso, albo, simplici, valde incrassato, marginibus dente 

 pliciformi, elevato, albo, triangular! junctis. 



Shell widely umbilicate, discoidal, flat, shining, translucent, 

 yellowish horn 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; umbilicus pervious, of equal size 

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

 stome depressel above, white, simple, much thickened wdthin, 

 the margins joined by a white pliciform elevated triangular 

 tooth. 



Diam. raaj. 11|^, min. IO5, Alt. 5 mill. 



Station. — Inhabits moss and decaying w^ood in the dampest 

 parts of the spruce forests. 



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

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



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

 with wdiich we are acquainted, hitberto found on the North 

 American Continent. Although entii'ely di-tinct from the 

 Bi'azilian II. polygyrata Born it has some affinity with it, espe- 

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

 internal teeth. H. polygyrata has five teeth within the last whorl, 

 three on the under surface of the outer w^all, and tw^o opposite to 

 the otliers on the exterior of the penultimate whorl. Our species 

 has two distinct rows of three teeth, all the teeth being on the 



