CONCHOLOGIA CESTRICA. $1 



S. avara, SAY, Long's Exped., II., 1822. 



Shell sub-oval, pale reddish-yellow; whorls 3, rounded, 

 with a deep suture ; aperture sub-ovate, s. avara, enlarged. 

 two-thirds the whole length. H. 6, W. rj gi 



, mill. 



Station, in damp pastures, lawns, etc. 

 Chester County ; common. 



Family PUPAD^E. 



Shell mostly small, cylindrical, ovate, or ovate-conical, 

 and elongated ; whorls numerous, the last not expanded ; 

 aperture sub-circular, simple, or armed with denticles ; 

 lip simple, or reflected ; umbilicate. Animal twice as long, 

 as broad ; broad, and square, in front ; head separated 

 from the foot beneath, by a transverse groove; head 

 transverse ; tentacles four, the upper pair, occuliferous. 



OBS. These pygmy mollusks are so minute as to 

 elude observation, unless specially sought for, in the 

 stations they inhabit. Some species are found in woods, 

 under the bark of decayed timber, while others occur 

 more abundantly under stones, boards, or chips, near the 

 margin of streams. Several species of Vertigo are found 

 abundantly, in grass fields, and lawns, or among moss. 

 In the latter stations, they may be readily captured 

 during the summer and early fall months by placing a 

 board on the wet grass in the evening ; to the under 

 surface of which they will be found closely adhering on 

 the next morning. Like most of their class, they are 

 vegetable feeders. In winter, they bury themselves in 

 the ground, or beneath decayed leaves. 



