INTRODUCTION. XV 



one another by the size, color, form, and various other cir- 

 cumstances of external appearance. There are, then, as 

 many species as there are sorts of animals. Thus the cat is 

 one species, the tiger is another, and the lion, leopard, 

 jaguar, and catamount are also separate species ; but taken 

 together with others, they constitute the genus Felis. Thus, 

 too, the genus Canis contains the dog, the wolf, the jackal, 

 and the fox, which are all so many distinct species. The ge- 

 nus Sciurus contains the gray, red, striped, and several other 

 kinds of squirrels. In treating of any particular animal, nat- 

 uralists are accustomed to designate it by a name derived from 

 its genus and species. This name is composed of two words, 

 the first being the name of its genus, and the second being 

 altogether arbitrary, or else expressing some circumstance, 

 relating to the color, size, or residence of the animal, which 

 serves in a degree to distinguish it from others. The first 13 

 called its generic, the second its trivial or specific name, and 

 they correspond very closely to the names of human individ- 

 uals, the generic terms answering to the surname, which 

 designates the family to which any one belongs, and the triv- 

 ial to the Christian name, which designates the particular 

 individual. 



To give an example : The different species of the genus 

 Felis, above mentioned, are distinguished one from another in 

 the following manner. The lion is called Felis leo ; the tiger, 

 Felis tigris; the leopard, Felis leopardus ; the jaguar, Felis 

 onca ; the lynx, Felis lynx ; the serval, Felis serval, &c. In 

 the genus Canis, the dog is called Canis domesticus ; the 

 wolf, Canis lupus ; the black wolf, Canis lycaon ; the fox, 

 Canis vulpes, &c. In this way, each animal is capable of 

 being clearly and accurately designated, by a name less liable 

 to mistake and confusion than its common one, which is 

 sometimes applied to several different species. This is called 

 the scientific or systematic name. 



Each sort of animal thus constitutes a distinct SPECIES ; a 

 number of species taken together form a GENUS ; those genera 

 which have important and well-defined points of resemblance 

 in structure and conformation are placed together in an ORDER ; 

 whilst upon a similar principle, but more extensive in its ap- 

 plication, these orders are marshalled into separate CLASSES ; 

 these, again, are arranged into distinct DIVISIONS ; which con- 

 stitute the two grand KINGDOMS of the whole animal world. 



