PREFACE ix 



photographs taken by myself with a whole plate 

 Sanderson camera for the Arnold Arboretum, and 

 permission to use them I owe to Professor Sargent. 

 The photographs were developed and printed by Mr. 

 E. J. Wallis of Kew, who obtained from the negatives 

 the best possible results. For the illustration of 

 Budorcas tihetanus, I am indebted to Mr. Samuel 

 Henshaw, Director of the Museum of Comparative 

 Zoology at Harvard College. 



It is quite impossible to record the full extent of 

 one's obligations, since much information is un- 

 consciously absorbed through contact with many 

 people and extensive reading. I should, however, 

 be lacking in filial respect did I not record my sense 

 of indebtedness to the Alma Mater who gave me both 

 inspiration and opportunity — the Royal Gardens, Kew. 



ERNEST H. WILSON 



The Arnold Arboretum 



Harvard University 



July 191 3 



