GASTEROPODA PULMONEA. 
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We ougfht to arrange near them some Helices which, without having a double-edged cloak, are equally incapable 
of retreating within their shell. Helix rufa and brevipes, Ferus., are examples. 
When the depth of the aperture is greater than its width, as is always the case in shells with an oblong or elon- 
gated spire, they are the terrestrial Bulimi of Brug., which it appears necessary to subdivide as follows : — The 
Bulimus, Lam., have an oval rim, thickened in the adult, but without denticulations. In tropical countries, there 
are some large and beautiful species ; some remarkable for the size of their eggs [equal to that of a Pigeon], and 
with an equally solid shell ; and others for their reversed shells. In our own country there are several of small or 
moderate size, and one of them {Helix decollata, Gm.) has the singular habit of breaking off in succession the 
whorls from its spire. This example has been quoted as a proof that the muscles of the animal can be voluntarily 
detached from the shell ; for a time does come when this Bulimus preserves no more than a single whorl of all 
those it possessed at the beginning of the decollation. 
The Pupa, Lam., have an obtusely-pointed shell, whose last w^horl is narrower than the penultimate, whence 
it has an elliptical, or sometimes a cylindrical form. The mouth is surrounded by a thickened rim, and en- 
croached upon, on the side of the spire, by the penultimate whorl. The species are very small, living in moist 
stations, amongst mosses, &c. There is sometimes no toothlet in the aperture, but oftener there is one or more 
either on the projecting part of the penultimate whorl, or within the outer margin. [The genera Vertigo, Miill., 
and Alcea, Jeffreys, appear to have been separated from Pupa on too slight grounds ; for the inferior tentacula are 
not absent, as is alleged, but only reduced to a minimum. The Partula, Fer., deserves probably to be kept dis- 
tinct ; for the species are ovo-viviparous, while all the others are oviparous.] 
The Chondrus, Cuv., has, as in these latter Pupae, the mouth of the shell encroached upon by the penultimate 
whorl, and guarded with plates or toothlets ; but the figure of the shell is more ovate, and more like that of the 
common Bulimi. Some have the teeth on the rim of the aperture, and others have plaits situated deeper within 
it. [This genus appears to be synonymous with the Azeca of Leach.] 
Here terminates the section of terrestrial Helices whose shell has a thickened oral rim \ox peritreme'\ in the adult. 
The Succinea, Drap., has an ovate shell, with an aperture longer than its width, as in Bulimus, but larger in 
proportion ; the outer lip sharp, and the side of the columella almost concave. The Snail is too large to be con- 
tained in it, and we may almost regard it as a Testacella with a big shell. The inferior tentacula are very small. 
It lives upon the herbs and the shrubs of the brinks of rivulets, whence it has been considered as an amphibious 
genus. 
We ought to separate from the genus Turbo of Linnaeus, and approximate near the terrestrial 
Helices, the 
Clausilia, Drap., — 
Known by the slender, long, and pointed shell, with the last whorl narrower than the penultimate in 
the adult, compressed, and a little detached. Its mouth is entire and margined, and often toothed or 
Fig’. 160. — A. zebra Fig. 161. — A. virginea. 
furnished Avith plates. There is mostly found, 
within the last whorl, a little lamina [commonly 
termed the clamium\, slightly curved, a little 
like the letter S, the use of which to the animal 
is unknown to us.* The species are small, and 
live in moss, at the foot of trees, &c. A great 
number of them are reversed. 
The Achatina, Lam. — 
Ought likewise to be separated from the BuU(r of 
Linnaeus, and brought hither. The oval or ob- 
long shell has the aperture of Bulimus, but is not 
margined ; and has the extremity of the colu- 
mella truncated, which is the first index of the 
emarginations we find in so many of the shells 
of the marine Gasteropodes. These Achatinae 
are large Snails which feed on trees and shrubs 
in hot climates.f Of such as have, within the 
last whorl, a callus or particular thickening, 
Montfort makes his genus Liguus. The body- 
whorl is proportionahly narrow ; and when the 
end of the columella is curved towards the in- 
side of the aperture, and the body-whorl is broader, the species constitute Montfort’s Polyphemes. 
* The use is to dose the aperture of the shell when the Snail has 
retired. See a good description of its mechanism by Mr. J. E. Gray, 
in Zool. Journ. vol. i. p. 212 . — Ed 
+ “ The greater number of Achatince,” says Sowerby, “are African 
shells : some are West Indian, and a very few European. Among the 
latter, -we can only lay claim to one as decidedly a native of this 
country, the A. acicula of Lamarck.”— Ei>. 
