advertisement. 
This Work will consist of twelve or fourteen Numbers (one Number to be published every 
two Months), which will form, when complete, one moderately-thick \ olumc. 
Although this Work is to be published miscellaneously, yet the Plates are numbered, to 
enable the Purchaser to arrange it systematically, when complete. 
The following species, viz. Astacus Arctus, and Mantis of Pennant, seem to have been 
introduced into the British Fauna on slender authority, and fragments of a species of the 
genus Squilla which were found by the late Mr. Boys in a Torbay trawl-boat, are preserved in 
the. cabinet of Montagu : information therefore on these or on other species is very desirable, 
and we shall feel obliged to any Naturalist who shall render us any assistance in making this 
publication as complete a9 possible. 
The mode of obtaining Crustacea is easy ; Crab and Prawn-Pits, also the rubbish taken 
from the bottom of the sea by dredgers, should be carefully examined, as either new or rare 
species often occur, and are rejected by the Fishermen as useless ; when obtained they should be 
immersed in fresh water, for the purpose of extracting the salt, after which they should be dried 
in the shade, and if possible, in a draft of air. 
