OF THE 



| UNIVERSITY 



V 



X^AL 



HISTORY OF CRUSTACEA. 



CHAPTER I. 



INTRODUCTORY. 



WHEN I had read Charles Darwin's book 'On the 

 Origin of Species,' it seemed to me that there was one 

 mode, and that perhaps the most certain, of testing 

 the correctness of the views developed in it, namely, 

 to attempt to apply them as specially as possible 

 to some particular group of animals. Such an 

 attempt to establish a genealogical tree, whether for 

 the families of a class, the genera of a large family, 

 or for the species of an extensive genus, and to pro- 

 duce pictures as complete and intelligible as possible 

 of the common ancestors of the various smaller and 

 larger circles, might furnish a result in three different 

 ways. 



1. In the first place, Darwin's suppositions when thus 

 applied might lead to irreconcilable and contradictory 

 conclusions, from which the erroneousness of the sup- 

 positions might be inferred. If Darwin's opinions are 

 false, it was to be expected that contradictions would 

 accompany their detailed application at every step, and 



