476 MURICID 2%. 
grounds. Many causes have concurred to produce this arti- 
ficial arrangement ;—amongst them, the multitude of species, 
the dissimilarity of the hard parts, which malacologists failed 
to see in their true light as the indices of species, choosing to 
consider the variable forms to proceed from generic animal 
distinction. We will examine these pots, and endeavour to 
reduce them to their proper value. 
The principal distinctions between this division and the 
Holostomata are, that the periphery of the aperture of the 
shells of the Canalifera is broken into branchial canals and 
more marked and extensive depuratory sinuses, and that the 
soft parts have invariably present a retractile proboscis, with 
some other variations that will be mentioned. The shells 
are of elegant structure and the animals of great beauty, 
but the latter resemble each other so much as only to admit, 
agreeably to my method, of the constitution of the single genus 
Murex, and even to render specific characters difficult without 
the aid of the hard parts, on which account I am obliged to 
enter upon more minute details than perhaps may be thought 
necessary. It will also be shown that the anatomy, as well as 
the hard and soft parts, with the general characters of the co- 
loration, especially in the minor Murices, are all but identical. 
There is a singular coherence in the specific descriptions ; 
this arises from the similarity of the objects; but if, to relieve 
the tedium of the “iterumque, iterumque,” I had attempted 
a generalization beyond what has been admitted, confusion 
would have resulted from the destruction of the individuality 
of the objects by amalgamated descriptive characters; the 
account would rather be that of a compound than of an indi- 
vidual animal, and the more delicate features so essential for 
specific comparison lost. If animals are to be described cor- 
rectly, conciseness must give way to particular description ; 
indeed, in zoological matters, the term serves for little else 
than to express the omission often of very essential features : 
but if it be msisted on, we must rest content with rough 
sketches instead of finished portraitures. 
The general distribution of the Muricide, according to my 
method, includes Lamarck’s Purpurifera, which have, as I 
