vi FOREWORD 



Natural History, with the cordial approval of President Osborn, has 

 at all times given indispensable support in the work of making ready 

 this book for the press. Special acknowledgment is due to Mrs. 

 E. H. Fink and Mrs. C. P. Meadowcroft of the Museum. Dr. G. K. 

 Noblcj Curator of Herpetology, has supplied critical notes on the 

 sections dealing with recent reptiles. 



Every effort has been made to keep intact the spirit and letter of 

 the original text, and in the few places where corrections or emenda- 

 tions seemed necessary they have been placed in square brackets, as 

 have also the footnotes that record some of the more conspicuous 

 discoveries and advances since 191 8. 



W. K. G. 



