ADVERTISEMENT. 
Wouen this Work commenced, it was the intention of the Author to have completed itin 
twelve or fourteen numbers, but the discovery of several new species has rendered this 
impossible; and he will, consequently, be under the necessity of extending it to nineteen — 
numbers, one of which will be published as usual, on the first day of every second 
month, and the new matter will be introduced in such a manner as not to disturb the systematic. 
arrangement of the work, which, when completed, will form one volume; to which © 
some general remarks on the British Crustacea, andan Index of Synonyms will be added. — 
Although the Work is to be published miscellaneously, yet the plates are s0 numbered, 
as to enable the purchaser to arrange it systematically, when complete, ase 
