110 Mr. W. Clark on the Muricidse. 



all have the double branchial plume, mucous fillets, and more or 

 less long branchial fold ; the stomach, liver, heart, auricles, ova- 

 rium, testis, andorgane geuerateur, nervous ganglia; in short, the 

 entire internal anatomy scarcely differs. The variations are spe- 

 cialties of small value, as of the size and outline of the foot and 

 its operculum where it exists, the different distances of the pedi- 

 culated eyes from the base of the tentacula, and the variations 

 in the external markings and contour of the hard parts ; with re- 

 spect to which we observe, that they arise solely from the vary- 

 ing disposition of the mucous glands of the mantle, combined 

 with the variety of food and habitat : but we think such variations 

 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 only meant aids for 

 the arrangement of vast numbers of species, such symbols can 

 be acccjitcd, though objectionable as to appellation, because with- 

 out explanation they would convey ideas of generic distinction 

 rather than of divisional assistance ; it is therefore better to con- 

 sider the variations of form and markings as simple sectional 

 guides to reduce an enormous family to comparatively easy iden- 

 tification 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 into numerous genera, 

 which are absolutely misnomers, being without generic distinc- 

 tion. For these reasons I shall consider all the British Cana- 

 lifera, and such of Lamarck's Purpurifera that comprise any of 

 our indigena, as represented on malacological grounds by the 

 animal of the ancient genus Murex, dividing the species into spe- 

 cific groups by the marked variations of the forms and sculptm-e 

 of the shells and by sectional indices and definitions. 



If however malacologists will not dispense with the old names 

 Buccinum, Fusus, Purpura, Nassa, &c., they must follow the bent 

 of their inclination ; it is hard to cast oft' old habits, however 

 much better ones may present themselves, " meliora probo, de- 

 teriora sequor :" but in our method they will bear in mind that 

 these words have the precise value of our sectional definitions ; 

 they are mere signs and mementos representing objects with 

 certain outward characters, but without the slightest generic pre- 

 tension. 



It may be objected that our sections and definitions are the 

 mere equivalents of the old Buccinum, Fusus, &c. : this is not so ; 

 these terras pretend to represent what does not exist — generic 

 distinction; but the sections merely point out variations of ex- 



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