SHELL. 
ed outer lip, terminating in a gutter which 
turns to tile left. 
26. Murex. Spiral and rough, with mem- 
branaceous sutures ; the aperture ending 
in an entire, straight, or soraewliat ascend- 
ing gutter. 
27. Troclius. Spiral, and nearly coni- 
cal ; the aperture nearly tetragonal or 
rounded, contracted transversely above j 
the columella oblique. 
28. Turbo. Spiral and solid ; the aper- 
ture contracted, orbicular, and intire. 
29. Helix. Spiral, subdiaphanous and 
fragile ; aperture close at the ends ; within 
lunated, or partly circular, as if a segment 
of the circle had been cut off. 
30. Nerita. Spiral, gibbous, and flattish 
below; the aperture semiorbicular, or semi- 
lunar ; the lip of the columella transverse 
and flattishly truncated. 
31. Haliotis. Ear-shaped; the mouth 
spread open ; the spire lateral and flat- 
tened ; the disc almost always perforated 
with a row of holes. 
32. Patella. Nearly conical and without 
a spire. 
33. Dentalium. Tubular straight, with 
one chamber, open at both ends. 
34 Serpnla. Tubular, adhering to other 
bodies, often intercepted by intire parti- 
tions. 
35. Teredo. Round, bending, and lodged 
wood. 
36. Sahella. Tubular, formed by grains 
of sand, on a membranous sheath. 
The French naturalists, whose late exer- 
tions have added much to the funds of this 
science, have thought it necessary to adopt 
some changes with respect to the preceding 
arrangement. These changes would, in- 
deed, derive some support from the high 
characters which have suggested them ; no 
one having done more of late years to the 
advancement of this species of knowledge 
than Bruguiere and Lamarck. Their ob- 
servations shall therefore be introduced un- 
der the several genera to which they apply, 
whilst the order in which they are taken 
shall be that of Bose, in “ Histoire Natu- 
relle des Coquilles.” . 
MULTIVALVE SHELLS. * 
Lamarck thinks that Pholades should be 
regarded as bivalves, having accessary 
pieces, and that the Oscabrions (Chitons) 
should be considered as naked mollusc®, 
whose backs are beset with small testace- 
ous lamin®. Bose, however, in conformity 
with accustomed practice, considers them 
among the multivalve shells. 
Dacosta (Conchology, 8vo. p. 97.) ob- 
serves that “ The Greek name lepas, al- 
ways synonimous with the Latin name pa- 
tella, the latter signifying little sacrifice 
dishes, or saucers, was given to limpets 
from the earliest Grecian times, and the 
Roman name from their resemblance to 
those little dishes ; yet Liimmus wantonly 
transposes the name of Lepas to the Balani.” 
The French naturalists have still continued 
the name of Lepas to the Patell®, and have 
separated those bodies which Linnmus had 
placed under the genus Lepas, into two 
genera : 1. Anatifa, a cuneiform shell com- 
posed of several flat unequal valves, con- 
nected together by a membrane, and united 
to the extremity of a tendinous tube fixed 
by its base ; and, 2. Balanus, a conical mul- 
tivalve shell, fixed by its base, and com- 
posed of six articulated valves, the openings 
closed by an operculum, with four valves. 
These shells had been united by Linnmus 
under one genus, most probably in conse- 
quence of the similarity of the animals by 
which they are inhabited ; but the French 
naturalists observe, in confirmation of the 
propriety of the distinction which they have 
adopted, that very essential differences ex- 
ist between the animals of the Anatif® and 
of the Balani. 
The Teredo is considered by Bose as a 
multivalve shell, formed of five unequal 
pieces ; the largest is a cylindrical tube, in 
which the others are contained. Two ex- 
tremely thin and nearly hemispherical pieces, 
resembling parts of a Pholas, pointed at one 
of their ends, and beset on their outer sur- 
face with twenty-five rows of small teeth, like 
those of a file, are placed at their lower 
extremity, and by their action remove the 
wood, and form the cavity in which tlie 
shell becomes lodged. At the superior ex- 
tremity, that which communicates with the 
water, are tw’o small roundish pieces, con- 
nected with the animal by cylindrical pedi- 
cles pbout their own length. When the 
animal stretches a little out of the tube, these 
valve-like pieces spread out, and when it 
re-enters, they contract and close the open- 
ing, through which the head, or rather the 
syphons of the animal had passed. 
Bruguiere has, apparently with much 
propriety, introduced a new genus which 
he has termed Fistulana, the characters of 
which are a tubular club-formed shell, open 
at its smaller extremity, and containing in 
its cavity two valves. The shell, the exa^ 
