vi PREFACE. 



by collecting the specimens and forming a little cabinet of 

 them. 



The difficulty, however, arises in commencing the les- 

 sons with either the lowest or the highest animals. If the au- 

 thor commences with the lowest animals, he deals at the out- 

 set with creatures which the pupil in certain cases can never 

 see, as many of the animals to be considered are microscopic, 

 and most of them of such a nature that their soft parts 

 cannot be preserved. On the other hand, if the author com- 

 mence with the vertebrates, he presents, point-blank, some 

 of the forms of structure most difficult to understand. 



The main thing at the outset is to teach the pupil how 

 to collect the objects for study ; this leads him to observe 

 them in Nature, and here the best part of the lesson is 

 learned : methods of protection for the young, curious 

 habits, modes of fabricating nests, and many little features 

 are here observed, which can never be studied from an or- 

 dinary collection. Hence, collecting in the field is of para- 

 mount importance. Next, the forming of a little collection 

 at home prompts the pupil to seek out certain resemblances 

 among his objects, in order to bring those of a kind together. 

 In this way he is prepared to understand and appreciate 

 methods of classification. Finally, having grasped the lead- 

 ing features of a few groups, he is enabled to comprehend 

 the character of cognate groiips with less difficulty. Thus, 



