14 ZOOLOGY. 
imal, and then to study in the same thorough manner an 
allied form, and, finally, to compare thetwo. 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 may be 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, Carnivoras 
Family, Felidae ;/ 
Genus, Felis ; 
Species, Felis‘domesticus Linneus ; 
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 gencalogi- 
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 
