

PREFACE 



In offering to the educational public this text-book in general 

 zoology, with its accompanying suggestions for laboratory work, 

 we desire to explain in brief the method of construction we have 

 followed. 



The treatment of the phyla is in a descending order from the 

 Arthropoda to the Protozoa, and in an ascending order from the 

 fishes to man. After many years of experience with classes of 

 young students we believe that an order of treatment resembling 

 this is likely to yield the best results, although we do not deny 

 that good results may be obtained with young students by follow- 

 ing what is sometimes called the " order of evolution," beginning 

 with the Protozoa. Although the chapters are interdependent, 

 we think that there is sufficient unity in each to make it possible 

 for the teacher to diverge from the order we have employed. 



Whatever the order followed, it is evident that recitation on 

 the chapters in the text-book should be held only after the pupil 

 lias made his study in the laboratory, for the text-book in science 

 has its greatest usefulness in connecting, extending, and illumi- 

 nating the work of the laboratory. Laboratory work brings the 

 pupil in touch with actual things, and if the studies are properly 

 conducted, they will aid in developing in the mind the power of 

 independent judgment. But the young and untrained student 

 cannot build up a conception of the science of zoology from the 

 more or less isolated data of the laboratory ; in this fact lies the 

 justification of a text-book in zoology. 



The function of the suggestions for laboratory work is to help 

 the pupil to make the be*st use of his time, and to direct him in 

 such a way that he will become more and more independent, 

 and be able to study intelligently without detailed directions. 

 It seems to us that the kind of directions given to pupils will 



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