^1 LISr?ARY 



ACKNOWLEDGMENTS X^> i^^^^si. 



r T IS a pleasure to acknowledge the help received from" 



sources in the preparation of this book. The Carnegie Institu- 

 tion through its Marine Biological Laboratory at Tortugas, 

 Florida, furnished excellent facilities for work; the Director, Dr. 

 W. H. Longley, and the Superintendent, Captain John Mills, did 

 everything possible to help in the study of migration problems. Dr. 

 A. V. Kidder and Dr. S. G. Morley made it possible to study the 

 cenotes and caves in Yucatan; Don Carlos Vales, Gustav Stroms- 

 veck, and Karl Ruppert greatly facilitated the work in the field. 

 The Rockefeller Foundation furnished funds and equipment which 

 permitted the writer to make observations in China, Siam, India, 

 and Nigeria. The following persons also materially assisted with 

 the work in the localities indicated: Japan — Prof. N. Yatsu and 

 Mr. N. Yosii, of the Misaki Biological Station, and Mr. S. Yoshi- 

 mura, of the Imperial University of Tokyo; Dean T. Kitashima, 

 Keio University; China — Prof. C. R. Kellogg, Pres. C. T. Lim, and 

 other members of Fukien Christian University; Siam — Dr. H. M. 

 Smith, Dr. Gordon Alexander, A. F. G. Kerr, A. Markan, E. D. 

 Congdon, Nai Pongse Phintuyotsin, Siri Habanananda, Prof. Max 

 MoUer, and Luang Manjijjprasitte; India — Dr. R. B. Seymour- 

 Sewell, Dr. S. L. Hora, Dr. Hem Sing Pruthi, and R. A. Hodgart, 

 all of the Indian Museum, Calcutta; Nigeria — Dr. F. F. Russell, 

 Dr. Henry Beewukes, and Rufus Gibson of the West African Yel- 

 low Fever Commission, and Dr. William Allen and F. A. Bemister, 

 administrative officers of the Nigerian government. Dr. I. E. Gray 

 has kindly read the manuscript for this book and made many help- 

 ful suggestions. My good friend Dr. Carl L. Hubbs made many 

 ^'-•lu^bl'* cii-^rrr-i^'ons for changes from the 1936 book. Dr. R. H. 

 Arnett, Jr., and Dr. R. E. Blackwelder also contributed photographs 

 and made helpful suggestions. 



A. S. P. 



[ix] 



