PREFACE ix 



the selection of facts and their arrangement differ from that 

 of existing text-books; in fact, this is not a text-book as that 

 term is properly used to-day when applied to extended treatises, 

 usually in more than one volume, which enter into the subject 

 exhaustively. Here the whole subject is epitomized ; the fun- 

 damental facts of the science, not the theories of the author, 

 are presented to the student; each subject is handled svnopti- 

 cally, not treated fragmentarily, as in the majority of the ele- 

 mentary books, which are for the most part adapted to children 

 only ; thus, the purpose has been to present a resume, readable 

 it is hoped, which shall be suited to the large class of students 

 for whom such a treatment is needed. Hence the title of the 

 work. 



I wish here to express my thanks to Miss E. Wood, palaeon- 

 tologist, formerly of the Massachusetts Institute of Technology, 

 and now connected with the Department of Geology at Wash- 

 ington, who was kind enough to read the chapter on prehistoric 

 animals in manuscript. I am also deeply indebted to my former 

 teacher, Dr. E. L. Mark, Professor of Zoology at Harvard, who 

 has read the preface and table of contents, and given me several 

 helpful suggestions on the general arrangement of the book. 

 And my thanks are especially due to Professor W. T. Sedgwick, 

 of the Massachusetts Institute of Technology, who has looked 

 over the entire manuscript and made valuable suggestions. His 

 continued encouragement and kindly interest during the prepa- 

 ration of the book have done much to lighten the drudgery of 

 compilation, so onerous in the elementary treatment of so broad 

 a subject as zoology has become to-day. 



A. W. WEYSSE. 

 Boston, Massachusetts, 

 August, 1903. 



