yi PREFACE 



\quarium, The Smithsonian Institution, ^Vard's Natural Science Estab- 

 lishment, Williams and AVilkins Company, and the United States Armv. 

 Our special thanks are due to members of the staff of the W. B. 

 Saunders Company Avho gaye us assistance and encouragement durmg the 

 long months of writing. Finally we want to express our thanks to Miss 

 Ann deNisco, Janet Loring and Mrs. Barbara Waller who helped m 



reading proof and preparing the index. 



Claude A. Villee 



Warren F. Walker, Jr. 



Frederick E. Smith 



March, 1958 



