366 
MOLLUSCA. 
The Murex, Linn.* — 
Embraces all shells whose canal is elongate and straight. I have found in the animals of all the sub- 
genera a proboscis ; approximated long tentacula, with the eyes external at their base ; a horny oper- 
culum, and no veil over the head : they otherwise resemble the Buccina, except in the length of the 
siphon. Bruguieres divided them into two genera, subsequently subdivided into others by Lamarck 
and Montfort. 
Murex, Brug., are all shells with a salient straight canal, and with varices across the whorls. M. Lamarck 
reserves this name specially to those in which the varices are not contiguous, so as to make two opposite rows. If 
their canal is long and slender, and the varices are armed with spines, they belong to the Murex of Montfort. 
If the varices are merely nodulous, 
they constitute his Brontes. Some, 
with a canal of moderate length, 
have projecting tubes between the 
spinous varices which penetrate 
the shell ; and these are the Ty- 
pMs, Montf. The CMcoracea of 
the same have, instead of spines, 
the varices garnished with plait- 
ed leaves, torn or divided into 
branches : their canal is long or 
moderate, and their foliaceous 
productions vary infinitely in 
shape and complexity. When, with 
Fijf. 184. — Murex tenuispina. j i i 
a moderate or short canal, the 
varices are only nodulous, and when the base has an umbilicus, the shell becomes an Aquilla, Montf. We have 
several species on our coasts. If there is no umbilicus, that marks the genus Lotorium. Lastly, when the canal 
is short, the spire raised, and the varices simple, the shell is a Tritonium. The mouth is generally grooved trans- 
versely on both sides. We have son»e large species in our seas. [The T. variegatum is much valued by the inha- 
bitants of some of the South Sea islands.] There are of them some with numerous, compressed, almost mem- 
branous varices, — the Trophones, Montf. ; and in others they are much compressed and very prominent, but few 
in number.f 
M. de Lamarck separates from all the Murices of Bruguieres the Ranella. Its character is to have the varices 
opposite, so that the shell is as it were girded with a border on two sides. Their canal is short, and the surface is 
roughened only with tubercles. The margins of their aperture are furrowed. The Apolles, Montf., are merely 
umbilicated Ranellse. 
Fusus, Brug., includes all the shells of this family which have no varices. When the spire is prominent, the 
pillar without plaits, and the margin entire, this is the Fusus of Lamarck, which Montfort has still further 
restricted, for he reserves this name to such as have no umbilicus. The less elongated and move ventricose 
species gradually approximate to the Buccina in their shape, and where they have an umbilicus, Montfort calls 
them Lathires. The Struthiolaria is another subgenus, distinguished by the inner lip being thickened and 
spreading over the lower part of the last volution and the columella, and in the adult the outer lip is thickened 
and turned outward, — a character that connects them with the Murex. When the spire is raised, the columella 
without plaits, and when there is near the top of the aperture, on its outside, a well-marked sinus or fissure, we 
have the characters of Pleurotoma, Lam. When this sinus is wide and touches the spire, some have seized the 
too slight distinction to make the genus Clavatula. When the spire is depressed, and the pillar without plaits, 
these are the Pyrula, Lam., which are either umbilicated or not. Montfort separates from Pyrula the species 
with a flattened spire, and which are striated within the mouth, to call them the Fulgur. They are in some degree 
Pyrulae with a plaited columella, and the plaits are sometimes even scarcely perceptible. Amid these dismember- 
ments of the Fusus, Brug., we distinguish the Fasciolaria, Lam., by some oblique and distinct folds on the 
columella, near the origin of the siphon. 
Turhinella, Lam., are likewise shells with a straight canal, without varices, distinguishable by having [from 
three to five] prominent, compressed, transverse folds, all nearly equal in size, near the centre of the columella, 
and which approximates them to the conical Volutae : in fact, they only differ by the superior elongation of the 
syphonal canal, [and in having an operculum, as well as a thickish epidermis]. 
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t 
The Strombusid^ (Strombus, Linn.) — 
Comprise the shells with a canal either straight or bent to the right, the external lip of the aperture 
becoming, in its maturity, more or less dilated, and always marked with a sinus near the siphonal 
canal, whence the head issues when the animal comes out. In the greater number this sinus is at some 
distance from the canal. 
* Coequal with the family SipJwnostoma of M. de Blairiville. 
t It is to be regretted that Cuvier should have given even the appearance of a sanction to these new genera of Montfort. — E d. 
