14 ZOOLOGY. 



imal, and then to study in the same thorough manner an 

 allied form, and, finally, to compare the two. For example, 

 take a frog and compare it with a toad, and then with a 

 newt, or a land salamander ; thus, by a study of the different 

 types of Batrachians, one may arrive at a knowledge of the 

 affinities of the different species of the class. The methods 

 of research are, then, observation and comparison. The 

 best and most philosophic observers are those who compare 

 most. Then, passing on to other animals, the student will 

 place in one group animals that are alike. He will find that 

 many agree in certain general characters common to all. 

 He will thus form them into classes, and those that agree in 

 less general characters into orders, and so on until those 

 agreeing in still less important characteristics maybe placed 

 in categories or groups termed families, genera and species, 

 varieties and races. For example, the cat belongs to the 

 following groups : 



Kingdom of Animals ; 



Sub-kingdom, or branch, Vertebrates ; 

 Class, Mammalia ; 

 Order, Carnivora ; 

 Family, Felidae ; 

 Genus, Felis ; 



Species, Felis domesticus Linnaeus ; 

 Variety, Angorensis. 



But these different groups are insufficient to represent the 

 almost endless relationships and series called the System of 

 Nature, which our classifications attempt to represent. 

 Hence we have sub-species, sub-genera, sub-families and 

 super-families, sub-orders and super-orders, and sub-classes 

 and super-classes, and the different assemblages may be 

 grouped into series of orders, families, etc. 



The relations of the members of these different groups 

 may be represented in the same manner as the genealogi- 

 cal tree of the historian, or like a tree, with its trunk 

 and branches and twigs ; or on a plane by a cross-section 

 through the tree, the different groups or ends of the 

 branches resembling a constellation, and embodying one's 



