INTRODUCTION. 
The principal object of the present Catalogue has been to 
give a complete list of the sjiecimens of Crustacea contained 
in the collection of the British Museum, indicating, at the 
same time, varieties, locality, and the source from whence 
they have been derived. 
With this view, the different individuals of each species 
contained in the collection are indicated by the letters a , 6, c, 
&c., following the name of the species, and its synonymes. 
The habitat is given a% particularly as the materials pos- 
many specimens have 
impossible to give the 
place from whence they are derived^ .except in the most gene¬ 
ral terms. 
Those specimens which have been presented to the Mu¬ 
seum have the name of the donor marked immediately after 
the habitat , and in general, the collection from whence the 
specimen has been purchased, or procured in exchange, is also 
marked; as it often gives some authenticity to its history. 
In the adoption of generic and specific names, it has been 
thought right to use, wherever it was possible, that which was 
sessed by the Museum permit; but as 
been procured from dealers, it is often 
