CONCHOLOGIA CESTRICA. 51 
S. avara, Say, Long’s Exped., IT., 1822. 
Shell sub-oval, pale reddish-yellow; whorls 3, rounded, 
with a deep suture ; aperture sub-ovate, $%. avara, enlarged, 
two-thirds the whole length. H. 6, W. Se 
3%, mill. 
Station, in damp pastures, lawns, etc. 
Chester County ; common. 
Family PUPADZ. 
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. 
Oss. — 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. 
