ACKNOWLEDGMENTS 



I should like to make grateful acknowledgment to the following for the 

 use of several of the photographs and illustrations within this book: the 

 Editors oi Discovery, Naturalist, The Field and Science News; G. Fryer, R. F. 

 Lawrence, E. A. Robins, J. H. P. Sankey, Duckworth & Co., Shell Photo- 

 graphic Unit, Zoological Society of London, and to Frank W. Lane for 

 photographs by Richard L. Cassell, Walker van Riper and Hugh Spencer. 



