PREFACE 



It is generally conceded that a satisfactory course in 

 zoology requires both laboratory study of animal forms 

 and lecture or text-book presentation of the laws of animal 

 life. The teachers most conversant with pedagogical 

 principles also contend that the greatest educational value 

 of the subject lies in the opportunity it gives to furnish 

 the student with an adequate first-hand knowledge of 

 organic evolution. To accomplish this a course in which 

 the pupil begins with the lower forms and works gradually 

 upward is necessary. For the pupil thus follows the de- 

 velopment of living things, seeing how each succeeding 

 form is an improvement over the one that went before, 

 and getting some idea of the great laws which govern the 

 growth and sequence of animal life. 



In his study of these forms of life the pupil -needs a 

 guide which shall lead him wisely without telling him too 

 much, and which shall stimulate him to see and to think 

 without bewildering, him with questions that he cannot 

 answer. In this little book such an attempt is made. 

 Since the directions were first used in my own classes 

 some ten years ago modifications have been made every 

 year, until in their present form I have found them thor- 

 oughly workable with average classes of beginners in 

 zoology. 



