Pupa found in the United States. A03 
the two last-mentioned ; umbilicus large and deep. 
Length less than ṣẹ of an inch; breadth J, of an 
inch. (^7 FAO 1 1 
This is the most minute species I have yet seen ; 
even more so than P. ertgwa. In size and outline 
it may be compared with P. vértigo, Drar., ( Vértigo 
pusilla of other authors) of Europe; but that isa 
reversed shell. The teeth are all distinct, long, com- 
pressed, and very sharp. I first discovered it at Oak 
- Island, Chelsea, on a warm, damp day, jin November, 
1839, crawling upon fallen leaves, in company with 
Bulimus libricus. Professor Adams has since found 
itin Vermont. It, doubtless, has a wide range, but 
its minuteness renders it difficult to be detected. — 
. PUPA SIMPLEX. 
"© plate III. fig. 91. 
P. testa minima, cylindraceá, obtusà, levi ; anfractibus sex, sub- 
planulatis; aperturá orbiculari, edentula. 
Shell minute, the two anterior thirds cylindrical, 
surmounted by a rapidly formed, blunt apex; light 
~ chestnut-colored. Whorls five, moderately convex, 
separated by a well-impressed suture, quite smooth ; 
aperture circular, excepting a slight encroachment 
by the preceding whorl ; lip simple, sharp, slightly 
everted on the left side, and partially hiding a small 
umbilicus. No trace of a tooth has been detected. 
Length ~, of an inch ; breadth +; of an inch. 
The only locality where this has been found is 
a small grove, a little northward of Fresh Pond, in 
Cambridge. In this place numerous specimens have 
