INTRODUCTION. 5 



animals in time is the subject-matter of P alee o zoology. The 

 facts of palaeozoology and the conclusions resting thereon are 

 among the most important in the whole realm of Zoology, 

 inasmuch as they supplement the facts gained from the study 

 of embryology and morphology of living species, thus enabling 

 the investigator to trace the history of the various races of 

 animals into the remote past. 



9. Practical Exercises. Let the student submit a written report on 

 the distribution of the animals in his immediate neighborhood, based on 

 his own observations. The report need not be exhaustive in order to 

 convince the student of the effect of the environment, which includes 

 everything in the surroundings, on the distribution of animals. Some 

 classification should be made of the varieties of territory included ; as 

 river, pond, lowland, woodland, prairie, mountain, and the like. Deter- 

 mine, by reference to the authorities available, the geographical distribu- 

 tion of the following: the elephant, the camel, the kangaroo, the horse, 

 the white bear, the seal, the salmon, the crocodile, the reef-forming coral, 

 the sponge of commerce. 



10. Classification. In studying animals and plants one is 

 soon impressed with the fact that among the thousands of 

 individuals, even of the same general kind, there are no two 

 exactly alike; and yet among them all, with their manifest dif- 

 ferences, there are numerous points of similarity. These two 

 facts make it possible to group those most alike into more or 

 less coherent classes, separating them at the same time from 

 other classes. The forming, naming, and defining of these 

 groups and subgroups we call Taxonomy or Classification. 

 Manifestly, true classification must depend upon the facts de- 

 rived from the completest possible study of the structure and 

 relations of organisms, and can only be perfect when we know 

 all that is to be known about them. In addition to displaying 

 our present knowledge of the relationship of animals, classifi- 

 cation serves a most important end in giving us more rapid 

 power of using that knowledge in getting further knowledge 

 that is needed. 



11. Historical. Zoology as a science can scarcely be said 

 to be more than three hundred years old, although Aristotle, 

 more than three hundred years before Christ, wrote much of 



