INTRODUCTION. 



THE principal object of the present Catalogue has been to 

 give a complete list of the specimens 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 as particularly as the materials pos- 

 sessed by the Museum permit ; but as many specimens have 

 been procured from dealers, it is often 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 



