vi PREFACE 



Then follows a general account of the branch to which 

 the example dissected belongs and brief accounts of 

 some of the more interesting members of the branch. In 

 these accounts technical directions are given for brief 

 comparative examinations and for the study of the life- 

 history and habits of some of the more accessible of 

 these forms. 



It will not be possible, of course, to undertake with any 

 thoroughness the consideration of all of the branches of 

 animals in a single year. But all are treated in the book, 

 so that the choice of those to be studied may rest with the 

 teacher. This choice will of necessity depend largely on 

 the opportunities afforded by the situation of the school, 

 as, for example, whether on the seashore or in the interior 

 near a lake or river, or on the dry plains, and on the re- 

 lation of the school-terms to the seasons of the year. 

 The branches are arranged in the book so that the sim- 

 plest animals are first considered, the slightly complex 

 ones next, and lastly the most highly organized forms. 

 But if in order to obtain examples for study it is necessary 

 to take up branches irregularly, that need not prove con- 

 fusing. The author would suggest that whatever other 

 branches are studied, the insects and birds, which are 

 readily available in all parts of the country, be certainly 

 selected, and with this selection in view has given them 

 special attention. Indeed some teachers may find these 

 two branches to offer quite sufficient work in classificatory 

 and ecological lines. 



Part III is devoted to a necessarily brief consideration 

 of certain of the more conspicuous and interesting 

 features of animal ecology. It has in it the suggestion 

 for much interesting field-work. The work of this part 

 should be taken up in connection with that of Part II, as, 

 for example, the consideration of social and communal 

 life in connection with the insects, parasitism in connec- 



