Fig-shells. MOLLUSCA. Rock-shei,ls. 323 
selves; and of late, conchological systematists have 
made various alterations in it. 
This family", as now constituted, contains those 
species, the animals of which have the siphon of the 
mantle and the canal of the shell long and straight, 
and the foot simple in front. The shell is spiral in 
form or pear-shaped, the pillar or columella smooth, 
the spire short, and the outer lip generally thin. The 
'operculum is not always present, but when it does 
occur, it is of an ovate figure, small in size, and 
acute or claw-shaped. The species are not numerous, 
but many of them are of considerable size, as the 
Fyrula (Cassiclulus) patula, from Panama, on the 
western coast of America, a rather ponderous shell 
with a large, ovate, expanded mouth, a broad, straight, 
open canal, and a very short spire ; the Pusus {Cassi- 
dulus) colosseus of Lamarck with a very long canal, a 
rounded form, generally covered with a rough, strong, 
epidermis, and as its name imports, of considerable 
magnitude, being indeed one of the largest species 
of the sub-order to which it belongs. They are 
natives of tropical seas, and the animals oi patula and 
melongerta, the one found on the mud banks of Panama, 
and the other in Jamaica, are used by the natives as 
food. Some of the species, especially those belonging 
to the sub-genus Fulgur, are reversed shells, that is, 
the whirls turn from right to left, and the mouth is on 
the left side of the axis when the shell is in its natural 
position. 
Family TI. — MURICIDiE {Rod-shells). 
The family of Rock-shells is the next in order. 
This is a very numerous family, and contains many 
of the largest and most beautiful shells that adorn 
our cabinets ; shells remarkable alike for the delicacy 
of their sculpture and variety of colours with which 
they are endowed. The animals have the mantle 
inclosed, and the margin produces ridges or varices 
at intervals across the shell, becoming extended in 
front, and forming a straight, more or less elongate, 
siphon. The shell is spiral, often tuireted, more or less 
extended at the fore part into a straight siphonal canal ; 
and the columella or pillar is smooth. The operculum 
is horny, annular, and has the nucleus apical or sub- 
apical. 
The ROCK-SHELLS, genus Murex of Linnseus, origi- 
nally contained a great many species which are now 
referred to several distinct genera. De Blainville and 
Lamarck separated many of these, and since their time 
others have been removed altogether, while several have 
been formed into sub-genera or groups. The recent or 
living species are numerous and are world-wide in their 
distribution, being most abundant on the west coast of 
tropical America, and occur also in numbers in China, 
Africa, and the West Indies. They are in general 
handsome shells, and are remarkable for having the 
whirls ornamented with three or more continuous, longi- 
tudinal ridges or varices, secreted by the margin of the 
mantle, as already stated, and generally formed on the 
completion of about a third of a whirl annually.* These 
* The animal, at certain periods of its growth, expands the 
edge of its mantle, and during this time deposits appendages 
varices are sometimes rounded or spinous, at others they 
are branched or foliaceous, and in some species again 
they are lamellar. The aperture is generally ovate, 
and in some species is contracted in front into a long, 
narrow, tubular canal, in others into a moderate or 
short canal, recurved or bent up to the right, often 
partly closed, and occasionally tubular. The oper- 
culum is ovate, with the nucleus sub-apical, within the 
apex. Among the species which have the rounded 
or spinous varices, and the long tubular canal forming 
the restricted genus Murex, we may mention the 
Murex cornutus of the Indian seas, commonly known 
by the name of Hercules’ Club, a prettily marked shell 
about seven inches in length ; the M. brandaris, a 
native of the shores of the Mediterranean, and which is 
often used by the Neapolitans as an article of food; 
and the M. crassispina and tenuispina, well known 
to collectors bj'- their names of the Thorny Woodcock 
and Snipe ; names derived from their long and slender 
canals or beaks; the latter also, from its numerous 
regularly arranged spines, being known to collectors 
by the name of Venus’ Comb. Among those species 
which have the varices garnished with plaited leaves 
torn or divided into branches (foliaceous), and the 
canal moderate or short and recurved (forming the 
Fig. 213. 
genus CMcoreus or Endive-leaf rock-shells), we find 
the varices vary in number, being generally either three 
or six, though sometimes more. In those which have 
only three branched varices, there is on each of the 
alternate divisions of the shell a more or less well- 
on the edge of its mantle for their protection ; these expansions 
of the mantle are then gradually withdrawn, and the portion ot 
the shell which the animal forms between this time and the 
next development of the appendages, is of the common shape ; 
but the expansions produced for their protection are left on the 
surface of the shell, forming variously shaped hands across the 
whirls, which have been called varices, from some of them 
looking like dilated veins ; these varices and the spines upon 
them, being formed on the expanded appendages of the mantle, 
exactly correspond to them in form, and afford good charac- 
ters for the determination of the groups and species. — Gray 
Synopsis of British Museum, 1S42. 
