FAMILY 2. COLIMACEA. 75 
There appears to have been some difference amongst authors with 
regard to the distribution of those species which were associated by 
Draparnaud under the title of Pupa. Linnzeus arranged them with the 
Turbines, Bruguiére with the Bulimi, De Férussac in his subgenus of 
Helices, Cochlodonta; and even in the present day some are for uniting 
them to the Bulimi, others to the Clausilie. They certainly run very 
closely into both of these genera; but inasmuch as the genus Pupa ma- 
terially assists the classification of so numerous a series, we consider that 
it may be retained with advantage. The Pup may be generally distin- 
guished by their cylindrical, turriculated form, and also by the last whorl 
not being enlarged. 
Vertigo, a genus proposed by Miller for certain small species with only 
two tentacula, has been adopted by some writers ; but this, again, is but 
a slight modification, for as the Pupz become smaller, their two anterior 
tentacula gradually diminish, until at last they altogether disappear. The 
Pupa elatior of Spix, a species remarkable for the number of its volutions, 
has also been distinguished by Lea with the title of Megaspira ; and the 
Pupa gracilis with its cognate species, together with several other species 
that are referred by some authors to the genus Clausilia, have been asso- 
ciated, on account of the margin of the aperture being continuous, and 
sometimes marked with a notch or groove; by Guilding under the title 
of Siphonostoma ; by Pfeiffer under that of Cylindrella. 
The shell of Pupa may be described as being of an oblong-cylindrical 
form, often rather thick, composed of many whorls, ribbed for the most 
part transversely, and sometimes forming a deep umbilicus ; the aperture 
is either round, or subquadrately oval, and generally more or less den- 
tated ; the margin is somewhat thickened, and the lip reflected. 
Examples. 
Pl. CLXX. Fig. 1. 
Pura pacopus, De Férussac, Prod., p. 59. Lesson, Voyage de la Co- 
quille, Zool., pl. 8. f. 6. 
Streptaxis pagodus? Gray. 
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