16 INTRODUCTORY 
Beak is that lengthened process in which the canal is situate ; 
it commences a little higher up, on the outside, than the insertion 
of the canal in the inside, which is always distinctly marked by the 
line of the aperture. Plate II. fig. 11, . This process is not so 
conspicuous in some of the species of Voluta, but is more marked 
in the genera Murex, Fusus, Pyrula, &c. 
Pillar, or columella, is that process which runs through the 
centre of the shell in the inside from the base to the apex in 
most univalve shells, and appears to be the support of the spire: 
and, indeed, seems to form that part of the shell: it is in general 
grooved or folded ; but, as it is situated in the interior of the shell, 
a minute description is unnecessary. Plate II. figs. 10 and 12, 
MM MMM; and Plate III. fig. 9, WWMM. The internal 
edge of its base is frequently described as having plaits, &c. 
Plaited Columella are those folds, or plaits, which are the dis- 
tinguishing characteristic of the Volute and other genera. Plate 
Ti. fie. N75. 
Pillar Lip is a continuation of the glossy process with which 
the aperture is lined, and expanded on the columella. Plate IU. 
figures 7 and 8, O O. This is termed the inner lip by some 
authors. 
Outer Lip. The expansion, or continuation of the body of 
the shell on the left margin of the aperture, and is also lined 
with the glossy process of the aperture. Plate II. fig. 7, 7; and 
Plate III. fig. 8, WW. The latter isan example of the alated 
or winged shells. 
Operculum, or lid. This is only an appendage to the turbi- 
nated or spiral shells affixed to the foot of the animal, sometimes 
of a testaceous, in others of a horny or cartilaginous substance. 
It acts as a door or lid, and is calculated for the protection of the 
animal, when it retires within its dwelling, from the intrusion of 
its enemies, and adapted to the shape of the aperture, which it 
closes nicely up: as exemplified in the operculum of the Turbo, 
and is of a hard, stony appearance. Plate III. fig.*4. 
Spire consists of all the whorls of the shell, except the lower 
one, which, as before observed, is termed the body of the shell. 
Plate IL. fig. 12, D; and Plate III. figures 7 and 8, D D. 
The spire is a prominent feature of the Univalve; and upon 
