192 CLASS III. GASTEROPODA. ORDER VII. PECTINIBRANCHIATA. 
and it appears to have passed, by a strange process of corruption, into 
that of Murex. We ascribe the formation of this genus to Linneus, 
because the canaliferous mollusks were indiscriminately associated by 
the earlier naturalists under the several titles of Murex, Purpura or Buc- 
cinum ; but it has since his time been variously and judiciously dismem- 
bered ; first by Bruguiére, for the introduction of his genera Fusus and 
Cerithium, and afterwards by Lamarck, for those which are now generally 
adopted. 
The shells of the Murices are chiefly distinguished by their profuse and 
elegant display of varices ; and when it is considered what an impediment 
the many spines and ramifications with which they are ornamented might 
offer to the regular volution of the whorls, it becomes both interesting 
and important to notice in what manner this emergency is provided for. 
The method is simply and beautifully contrived: the Murices, like many 
other mollusks, appear to have the power of slowly abrading any portion 
of their shell by means of some powerful solvent, and of thus removing 
every obstacle to its growth. The shell of the Murew cornutus exhibits 
this mode of operation distinctly : on the left of the aperture, just above 
the columella, may be seen the remains of.a spine, which has been re- 
moved for the purpose of spreading the finishing layer of enamel. The 
varices are said to be formed by certain parts of the mantle, which are 
projected only at intervals, for the purpose of furnishing a protective mar- 
gin to the shell, during a period of rest. 
The following Murices have been selected by De Montford as types for 
the formation of new genera: the Murez inflatus, as having three rami- 
tied varices on each whorl, for that of Chicoreus ; the Murex haustellum, as 
having a long closed canal, for that of Brontes ; and the Murew tubifer, as 
having an open tubular spine between each of the varices, for that of 
Typhis. The last of these genera is certainly the most entitled to con- 
sideration ; but we still think with Deshayes that it may retain all its 
importance as a sectional division of the primitive genus. 
The shell of Murex may be described as being ovate or oblong, with 
the spire for the most part prominent, and rather acute at the apex ; the 
whorls are slightly convex, and are remarkable as having the surface more 
