PREFACE 



This text is designed primarily for use in a half-year course in 

 Comparative Anatomy. To attain this end it was necessary to 

 reduce the amount of detail that is included in the usual text 

 and to arrange the material for flexibility. Additional material 

 for those who desire it will be found in separate sections. The 

 author makes no apology for the omission of anatomical minutiae. 

 Such technicalities usually do not have wide application, and 

 often so confuse the student that the central theme is lost. 



An attempt has been made to simplify the descriptions of 

 development from the generalized to the specialized, yet, at the 

 same time, to emphasize the essentials of anatomy. For this 

 reason enough natural history is included to make clear the com- 

 parison of structures and to show the evolutionary implications 

 of anatomy. 



The result of a desire for simplification and flexibility is a book 

 in three parts, each to a certain extent independent of the others. 

 Chapters are numbered consecutively, and each is divided into 

 sections, so that the instructor may omit certain chapters or sec- 

 tions without destroying the continuity of the book. 



Vertebrate Zoology, part i, considers the systematic rela- 

 tionships of the groups of vertebrates. A study of the compara- 

 tive anatomy of organs {systemic anatomy) presupposes this 

 knowledge of the vertebrates, for it is impossible to compare un- 

 known entities. In addition, the author is sufficiently attached to 

 the "Old School" to believe that a student, whether pre-profes- 

 sional or general, should know the major groups of animals as he 

 knows the major periods of history. 



Each vertebrate class is included in a separate chapter. At the 

 beginning of each chapter is a general discussion, and this is fol- 

 lowed by discussions of the more important orders. Those orders 

 which have a direct bearing upon the evolution of man are in- 



