sketch of the Natural History of the 

 Crustacea deals chiefly with their habits and 

 modes of life, and attempts to provide, for readers 

 unfamiliar with the technicalities of Zoology, an 

 account of some of the more important scientific 

 problems suggested by a study of the living animals 

 in relation to their environment. 



I am indebted to the Trustees of the British 

 Museum for leave to reproduce certain figures pre- 

 pared for the " Guide to the Crustacea, Arachnida, 

 Onychophora, and Myriopoda exhibited in the 

 Department of Zoology "; also to Sir Ray Lan- 

 kester, K.C.B., F.R.S., and to Messrs. A. and C. 

 Black for the use of a number of figures from my 

 volume on Crustacea in the "Treatise on Zoology," 

 edited by Sir Ray Lankester. 



