478 MURICIDZ. 
armed with hard parts of variable lengths for boring and 
sucking their prey. They all have the double branchial plume, 
mucous fillets, and more or less long branchial fold; the sto- 
mach, liver, heart, auricles, ovarium, testis, organe générateur, 
and nervous ganglia, in short, the entire internal anatomy 
scarcely differs. The variations are specialties of small value, 
as the size and outline of the foot and its operculum, the 
different distances of the pediculated eyes from the base of 
the tentacula, and the variations in the external markings 
and contour of the hard parts; with respect to which we may 
observe, that they arise solely from the varying disposition of 
the mucous glands of the mantle, combined with the variety 
of food and habitat: but we think such differences do not 
constitute generic distinction. 
Conchologists will ask, if the present numerous genera of 
this family are merged in the single one of Murex, how are 
they to distribute the multitudinous species? The only answer 
is, not by dividing the simple genus into twenty others of 
similar characters. If the genera of these gentlemen are 
intended only as aids for the arrangement of vast numbers 
of species, such symbols might be accepted, though objec- 
tionable as to appellation, because, without explanation, they 
would convey ideas of generic distmcetion rather than of 
divisional assistance; it is therefore better to consider the 
variations of form and markings as simple sectional guides 
to reduce an enormous family to comparatively easy identi- 
fication of its species. It is a very illogical position, that 
because a genus happens to have a thousand species or more 
instead of ten, it is on that account to be cut up mto 
numerous genera, which are absolutely misnomers, being 
without generic distinction. For these reasons I shall con- 
sider all the British Canalifera, and such of Lamarck’s Pur- 
purifera as comprise any of our indigena, as represented on 
malacological grounds by the animal of the ancient genus 
Murex, dividing the species into specific groups by the marked 
variations of the forms and sculpture of the shells, and by 
sectional indices and definitions. 
If, however, malacologists will not dispense with the old 
