animals is concerned with the causes of this process, as 

 what we may venture to call the physiology of evolution. 

 In brief, then, the great questions of zoology are the what 

 and the how of evolution. 



In view of the earlier lectures, it is unnecessary to speak 

 at length of classification or taxonomy the first division 

 of static or structural zoology. Aristotle, who gathered 

 and studied some five hundred of the more common ani- 

 mals of the earth and shore and sea, and the mediaevalists 

 Wotton and Ray, Gesner and Aldrovandi, were animated 

 primarily by the instincts of the collector of interesting 

 information. Linnaeus, the great figure of the eighteenth 

 century, rendered an immortal service to zoology (and 

 botany, too,) by introducing the present ordered system of 

 naming and classifying organisms. But classification was 

 to Linnaeus an end in itself, he could not see that it was 

 but a means to the larger end of understanding and ex- 

 pressing evolutionary relationships, that resemblance 

 meant consanguinity. It remained for Erasmus Darwin, 

 the elder St. Hiliare, Lamarck and others to appreciate 

 this inner meaning which so vivifies the otherwise dead 

 details of taxonomy. 



The many connected details of animal structure and 

 development and function constitute the threads, as it were, 

 which are interwoven by comparative treatment to form 

 the warp and woof of the fabric of zoology. Classifica- 

 tion draws upon this fabric the pattern of genealogical 

 connections, emphasizing those threads that run furthest, 

 the so-called distinctive or diagnostic characters. And 

 though the pattern must be altered here and there as 

 knowledge increases, the zoologist feels that it has a real 

 significance as a representation of evolutionary descent. 



As more and more of the lower animals were brought 

 by the microscope from the obscurity of their zoological 

 underworld, as exploration revealed more of the creatures 



8 



