348 
MOLLUSCA. 
The Vaginulus, Feruss.* — 
Has a close-fitted cloak without a shell, extended over the whole length of the body ; four tentacula, 
of which the inferior are somewhat forked ; the anus quite at the posterior extremity, between the end 
of the cloak and that of the foot ; and the same orifice leads to the pulmonary cavity situated along 
the right flank. The orifice of the male organ of generation is under the right inferior tentaculum, and 
that of the female organ under the middle of the right side. These organs, as well as those of digestion, 
are very similar to those of the Snail. The genus belongs to both Indies, and is much like our Slugs. 
The Testacell^, Lam. — 
Have the respiratory aperture, and the anus, near the posterior extremity ; their cloak is very small, 
and also placed there, and contains a small ear-shaped shell, which does not equal one-tenth of the 
length of the body. In other respects, these animals resemble our Slugs. 
One species is found abundantly in our southern 
Fig-. 158.— The Testacella. 
departments {Testacella haliotoidea, Diaparn.), 
living under ground, and feeding principally 
on earth-worms. M. de Ferussac has observed 
that its cloak assumes an extraordinary develope- 
ment when the animal finds itself in too dry a 
situation, and thus produces for itself a sort of 
shade and shelter. 
[There are some interesting illustrations of the 
habits of the Testacellae in Loudon’s Magazine 
of Natural History, vol. vii.] 
Cuv. — 
The Parmacella 
Has a membranous cloak, wdth loose margins, situated [upon a gibbosity] in the middle of the back, 
and containing, in its posterior part, an oblong flat shell, which exhibits the mere vestige of a spine. 
The respiratory aperture, and the anus, are under the right side of the middle of the cloak. 
The first known species was from Mesopotamia {Par. Olivieri, Cuv.) ; but we have now one from Brazil, and 
some others from India. 
In the terrestrial Pulmonea with a perfect and exterior shell, the margin of its aperture is in general 
thickened and reverted in the adult. 
Linnaeus referred to his genus 
Helix, — 
Every species in which the aperture of the shell (somewhat encroached upon by the projection of the 
penultimate whorl) assumes a crescent-like figure. 
When this lunated aperture is wider than it is deep, the shells belong to Helix, Brug. & Lam. In some, the 
shell is globular. Everybody knows the edible Snail {Hel. pomatia, Linn.), common in gardens and vineyards, 
and esteemed as a delicacy in some departments ; and the common Snail {Hel. nemoralis, Linn.), remarkable for 
the vividness and variety of its colours, and very 
hurtful to garden stuffs in wet seasons. There is 
no one who has not heard of the curious experi- 
ments, showing to what extent they can reproduce 
amputated parts. 
Other species have a depressed shell, or one with 
a flattened spire ; and we ought not to pass over 
without notice such as have interiorly projecting 
ribs, nor those in which the last whorl is abruptly 
turned up in the adult [so that the aperture appears 159. — Anastoraa globosa 
in the same plane as the spire], and then assumes 
an irregular plicated form,— hence denominated Anastoma\ by Lamarck. 
The Vitrina, Drap. {Helico-Limax, Feruss.), are Helices with an extremely thin subspiral shell, without an um- 
bilicus, and with an ample aperture, whose margin is sharp and even. The body of the Snail is too large to be 
drawn within the shell. The cloak has a double edge ; and the superior fold, which is divided into several lobes, 
may be made to overlap the shell so as to clean and polish it. The European species live in moist situations, and I 
n 1 __x ai'Ta 111 wiirm 
are very small ; but there are some of large size in warm climates. 
* Synonymous -with the Onchidium of Buchanan ; and the F eroni- 
cella of Blainville is not different. — E d. 
t “The peculiarity -which distinguishes this genus from all the other 
Heliciform Univalves is so extraordinary, that it appears to us to be 
deserving of particular notice, inasmuch as it evidences a consider- 
able alteration in the habit and economy of the animal which produces 
it, at the time of its arrival at its last period of growth, when it forms 
the reflected outer lip, and the teeth in the aperture. Until then, the 
animal must crawl about like other Snails, with the spire of its shell & 
uppermost ; but as soon as it arrives at maturity, and is about to form 
its complete aperture, it takes a reverse position, and afterwards 
constantly carries its spire downwards.”— Sowekbt. Two species 
are known.— Ed. 
