advertisement. 
The Author of this work announced in 1810, on part XVII, that it was his intention 
to complete it in nineteen parts j however, he stopped short then. Upon the stock becoming 
my property, I adopted the suggestion of Mr. George Brettingham Sower by, the eminent 
Naturalist, that the work should be continued, by the addition of such species as formed 
part of the author’s original plan: that gentleman has now drawn for the work fifteen new 
species, on six entirely new copper plates, to which is added a descriptive letterpress 
AND A COMPLETE GENERIC AND SPECIFIC INDEX TO THE WHOLE WORK: to this issue is 
further added plate 35, a very large figure of a lobster which remained unfinished at 
the abrupt cessation of the work. 
The new matter is arranged in such a manner, that while the gaps m the numbering 
of the plates are filled up, the systematic arrangement is not disturbed ; and by means of 
these additions the unfinished work of Leach and the elder Sowerby is arranged and completed. 
Possessors of imperfect copies should avail, themselves of the present opportunity of 
completing them, as only a small number of parts 18 and 19 were printed in excess. 
A few copies of parts 18 and 19 were printed on Large Paper, super royal quarto. 
Bernard Quaritch. 
London, 15 Piccadilly, W. 
November 1, 1875. 
