NOTE 



The author wishes to express his sincere in- 

 debtedness and gratitude to Mr. Franklyn Everett 

 Fitch and Mr. Henry Clay Foster for their valua- 

 ble and scholarly assistance in the final prepara- 

 tion of this book. 



He acknowledges, also, his indebtedness to 

 The American Museum of Natural History, New 

 York, for most of the photographs used to illus- 

 trate the book. . 



