154 UNIVALVE SHELLS 



5. H. *clausa. Shell fragile, slightly perforated, 

 subglobular, yellowish horn-colour, above convex.; 

 whorls four or five; aperture slightly contracted by 

 the lip; lip reflected, flat, white, nearly covering the 

 umbilicus. 



Inhabits Illinois. 



Greatest breadth, fr6m one-half to three-fifths of 

 an inch. 



A small and handsome species, which somewhat 

 resembles albolabris, but is much smaller, more 

 rounded, and is sub-umbilicate. This shell also oc- 

 curs though perhaps rarely in Pennsylvania. 



6. H. *obstrida. Shell depressed, with elevated 

 lines forming grooves between them; epidermis pale 

 brownish, naked; volutions five, depressed above, 

 beneath rounded, with an acute projecting carina; 

 umbilicus covered with a white callus, indented ; 

 mouth resembling that of H, palliata. 



Inhabits Ohio. 



Breadth nearly one inch. 



This species is very closely allied to Helix pal- 

 Uata, but the epidermis is not covered with small ele- 

 vations as in that shell, and the carina is very pro- 

 minent and remarkable. 



7. H. *elevata. Shell pale horn colour, spire 

 elevated; whirls seven, regularly rounded; umbilicus 



