GALLERY.] NATURAL HISTORY. Ill 
of the shell is generally granulated; as in the genera 
Ranella, where there is half a whorl between each varix, 
and Triton , where there is a varix on each two-thirds of a 
whorl. In the Murices, on the contrary, the expansions of 
the mantle are generally produced into elongated processes, 
the varices are consequently spinose or variously branched, 
and there is only one-third (or often less) of a whorl between 
them : the inner lip of these shells is smooth. In the other 
genera of this family the animal does not, or only very 
slightly, dilate the mantle at any period of its growth, so 
that the shell has a uniform surface, or marked with only 
slightly concentric waves, which may be considered as the 
rudimentary states of varices, or rather as the intermediate 
ridges which are found between the varices in the Tritons 
and Mur ices, and which mark the places where the animals 
have rested for a short period; their ridges are generally 
fringed with an expansion of the periostraca. In some of 
the genera, as Pleurotoma, Conus, Fusus, and Pyrula, the 
pillar of the shell is smooth. In others, as Turbinellus, 
Fasciolaria, and Cancellaria , this part is plaited as in the 
Volutes, but they are known from the latter by the canal 
of the syphon being more elongated. 
The family of Buccinidce (Case ) have the syphon of 
the mantle recurved, and the shell has a more or less 
elongated recurved canal in the front of the mouth for its 
protection. Some of these animals form convex rounded 
varices at distant places on the whorls, like the Tritons , 
and generally have the lips veined or granular, as Cassis , 
Cassidaria , Folium, and Harpa. Others, like the Murices, 
have close irregular varices, which are sometimes produced 
into spines or branched processes, as Ricinula, Purpura, 
and Magilus. The latter is very peculiar; for the animal, 
at a certain period of its growth, deposits in the cavity such 
a quantity of calcareous matter, as to produce the shell, in its 
subsequent growth, into a more or less elongated straight 
process. In others the animal does not form any, or only very 
rudimentary, varices, as Buccinum, Terebra, Nassa, and 
Columbella, and the shells are covered with a horny pe¬ 
riostraca. These genera are severally distinguished from 
each other by the form of the mouth ; some of them, which 
have the lips much dilated over the base of the last whorl, 
have a very large foot, which is believed to secrete the 
