298 AMERICAN JOURNAL 



MONOGRAPH OF THE TERRESTRIAL MOLLUSCA OF THE 

 UNITED STATES. 



BY GEORGE AV. TRYON, JR. 

 [Continued from page 174.] 



Family PUPAD^. 



Shell cylindrical, with generally obtuse apex, the whorls 

 numerous and nearly equal; aperture small, rounded, with 

 expanded or reflected lips, and generally armed with teeth or 

 lamin{ie within. Minute in size in most of the North American 

 species. 



Animal. — Tentacles very small or wanting; foot short, obtuse 

 or pointed behind. 



Remarks. — These shells are the smallest of all the terrestrial 

 mollusca inhabiting the United States (except P. incana, which 

 is a large species, but belongs to a West Indian group). They 

 are so minute, indeed, that it requires the strictest scrutiny of 

 the damp ground, moss, or decayed wood inhabited by them, in 

 order to detect their presence, a difficulty which is much increased 

 by their color, which is dull and earthy. 



Genera. 



ClONELLA, Jeffreys. Oblong-acuminate, smooth, polished ; 

 aperture small, oval, with a short, arcuate, more or less 

 truncated columella. 



Stenogyra, Shuttleworth. Cylindrically turrited, generally 

 truncate at apex, epidermis corneous, shining ; aperture 

 small, oval, columella truncate. 



