of North American Ilelicidoe. 443 



2. Two teeth within at base of aperture. 

 H. suppressa Say. 



" gnlaris " 



3. Two internal lamella;. 

 II. lasnioilon Phill. 



4. Two or more internal teeth repeated in two or more series. 

 II. lineata Say. 



" interna " 



" multidentata By. 



B. Lip reflected — no fulcrum. 



5. One parietal tooth,* 

 II. exoleta By. 



" thyroides Say. 

 '"• bucculenta Gould. 

 " AVheatleyi Bland. 

 " dentifera By. 

 " Roenieri Pfr. 



" Christyi Bland — allied in form to 11. inflecta Say. 



6. One tooth on loioer lip.\ 

 H. profunda Say. 



" Pennsylvanica Green, tooth not prominently developed. 



7. One parietal toothy and one on lower lip. 

 II. Sayii By. 



8. One parietal tooth, and one {lamelliform) on loiver lip. 



11. elevata Say — var. without lip tooth. 



" Clarkii Lea. 



" appressa Say — var. with outer lip tooth, like H.palliata. 



9. One parietal tooth, one {lamelliform) on loiver lip and one on 



outer lip. 

 H. palliata Say. 

 " obstricta " 



* H. albolabris not unfrequently, and H. multilincata rarely hare this tooth, 

 f H. albolabris, exoleta, and thyroides have often a tooth-like callus on the lower 

 lip near its eoluinellar termination. 



