4 PREFACE 



The pedagogical importance of laboratory and field 

 study has led to the introduction of a series of exercises 

 upon the structure, physiology, and habits of represen- 

 tative animals. These exercises suggest the more im- 

 portant topics for study rather than give an inflexible 

 outline to be followed in detail. The teacher is thus 

 left free to adapt and modify the laboratory course to 

 suit the peculiar needs of his classes and his equip- 

 ment. The exercises lead to the study of Systematic 

 Zoology, to which they serve as the natural introduc- 

 tion, the classification of animals being based upon 

 their structural relationships. With the anatomy of 

 the typical forms examined in the practical exercises 

 in mind, the student ought to have no trouble in under- 

 standing the structural modifications mentioned in the 

 descriptions of the principal classes and orders. Hav- 

 ing thus enlarged his view of the animal kingdom, he 

 is in position to appreciate the elementary facts of 

 Comparative Zoology and to understand the main fea- 

 tures of the current zoological theories. Believing this 

 to be a logical sequence of study, the book has been 

 arranged in accordance therewith. With the exception 

 of slight changes, the laboratory exercises are the same 

 as those recommended by the New York State Science 

 Teachers' Association. The system of classification 

 adopted is that given by Parker and Haswell in their 

 " Text-book of Zoology," a work which will long be a 

 standard of reference for teachers in secondary schools. 

 Part I and Part II of Professor Orton's book have been 

 transposed so as to place classification before the dis- 



