THE CLASSIFICATION OF ANIMALS 51 



most of the technical words used in naming the parts of animals 

 and plants are Latin. So that Latin may be called the language 

 of science. For most of the groups of animals we have English 

 names as well as Greek or Latin ones and when talking with an 

 English-speaking person we can use these names. But when 

 scientific men write of animals they use the names which have 

 been agreed on by naturalists of all nationalities and which 

 are understood by all of these naturalists. These Latin and 

 Greek names of animals, laughed at by non-scientific persons 

 as "jaw-breakers," are really a great convenience, and save 

 much circumlocution and misunderstanding. 



Zoological Classification and Nomenclature. In any dis- 

 cussion of the nomenclature of zoological classification it is 

 first of all necessary to distinguish between the few names 

 used as common nouns, such as species, genus, family, order, 

 etc., which denote the different kinds of groups into which 

 animals are divided, and the host of proper noun names which 

 are applied to the many groups of each kind which have been 

 established by students of systematic zoology. 



A single kind of animal, as a house-fly, a robin or a coyote, 

 is called a species of animal. Coyotes, dogs and gray wolves 

 are different species much alike. They are grouped together 

 with some other kinds of wolves and dog-like animals to form 

 a group called a genus. The robin belongs to a genus which 

 includes one or two other robin-like species of birds and the 

 house-fly to a genus which includes several other house-fly 

 species of insects. Each of these genera has a proper name, 

 which distinguishes it from all other genera, and for that matter 

 from all other groups of animals, because a genus name is 

 never used for more than one group of animals. The dog- 

 coyote-wolf genus is called Canis, the robin genus, Merula, 

 and the house-fly genus, Musca. 



Each species belonging to these genera also has a specific 

 proper name, the dog's species name being familiaris, the 

 coyote's latrans, the gray wolf's occidentalis, the robin's migra- 

 loria, and the house-fly's domestica. But because of the 

 enormous number of kinds of animals we do not try to have 

 a separate single word name for each species, but always com- 



