XXX A HISTORY OF BIRDS 



various mechanisms of flight in animals and their rela- 

 tion .to other locomotor organs. 



It is distinctly a feature of Mr. Pycraft's book that he 

 has given a larger number of illustrative examples of 

 adaptation to environment, of homoplasy and parallelism, 

 than is to be found in any other book on birds. 



E. RAY LANKESTER 



