CHAPTER V. 



A VIEW IN PERSPECTIVE. 



AFTER this outline sketch of the history of the 

 animal kingdom, we may now try to take a perspec- 

 tive view of the whole, in order to get a better 

 understanding of the true significance of the history. 

 Details of science are of little interest or of little 

 significance until they are collected into groups and 

 formulated into laws ; and a bird's-eye view gives us 

 a clearer idea of relations than an elaborate study of 

 details. 



Perhaps the most striking point which forces itself 

 to our attention is one already noticed, viz. : the 

 great extent to which the development of the ani- 

 mal kingdom had taken place even prior to the 

 beginning of the fossil period. In the outline of the 

 history of animals as sketched in the previous chap- 

 ter, it has been seen that all the groups of animals 

 except the insects and vertebrates had already 

 reached a high state of development before the 

 Silurian. In many of them there has been almost 

 no change since that time. In others, the change 

 has been chiefly in the addition of new families and 

 genera without any special modification of type. 

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