GASTEROPODA. 93 
Pupa (Vertigo) tantilla, Goutp; Proceed. Boston Soc. Nat. Hist., 
i. 197. March 1847. Expedition Shells, 33. 
SHELL very minute, of an oval form, obtuse at summit, and com- 
posed of about four convex whorls, of which the upper ones are irre- 
gularly marked with delicate longitudinal bars, and the lower one, 
under a magnifier, appears to be roughened by minute, irregular gra- 
nulations. Colour whitish. Aperture somewhat four-sided, rounded 
at the corners, the lip slightly expanding, and the throat armed with 
five teeth, one on the columella, one at the base, one on the outer lip, 
and two unequal approximate ones on the middle of the transverse lip. 
There is a small umbilical fissure. 
Length of axis one-fifteenth of an inch; width one-twentieth of an 
inch. 
Inhabits the mountains of Tahiti, at an elevation of two thousand 
feet. Couthouy. 
This little shell, the only one of this type which has come to us 
from the Pacific region, has about the size and shape of P. Gouldit, 
Binney, and the same number of teeth; but two of them are on the 
transverse lip instead of on the pillar. 
Pura PEPONUM (Gould). 
Testa minuta, variabilis, ovata, plus minusve elongata, tenuis, lucida, 
nitida, fulvo-cornea, perforata: spira anfractibus sex convexis leviter 
striatis: apertura ovato-rotundata, posticé lamellam volventem gerens ; 
labro simplici, ad columellam plerumque late revoluto ; columella vel 
nuda vel lamellis transversis ad tribus instructd. 
Pupa peponum, Gouin; Proceed. Boston Soc. Nat. Hist., ii. 197. 
March 1847. Expedition Shells, 34. 
SHELL minute, very variable in its form and characters, thin, 
shining, lucid and fragile, of an ovate or much elongated ovate form, 
of a yellowish horn-colour, its surface delicately marked with lines of 
increment, and with an umbilicus which is sometimes quite small, 
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