SPECIES AND BREEDS. 137 



From a comparison of a number of well-known 

 Species belonging to a natural Genus, it is not 

 difficult to ascertain what are essentially specific 

 characters. There is hardly among Mammalia a 

 more natural Genus than that which includes the 

 Rabbits and Hares, or that to which the Rats and 

 Mice are referred. Let us see how the different 

 Species differ from one another. Though we 

 give two names in the vernacular to the Genus 

 Hare, both Hares and Rabbits agree in all the 

 structural peculiarities constituting a Genus ; 

 but the different Species are distinguished by 

 their absolute size when full-grown, by the na- 

 ture and color of their fur, by the size and 

 form of the ear, by the relative length of their 

 legs and tail, by the more or less slender build 

 of their whole body, by their habits, some liv- 

 ing in open grounds, others among the bushes, 

 others in swamps, others burrowing under the 

 earth, by the number of young they bring 

 forth, by their different seasons of breeding, 

 and by still minor differences, such as the perma- 

 nent color of the hair throughout the year in 

 some, while in others it turns white in winter. 

 The Rats and Mice differ in a similar way : there 

 being large and small Species, some gray, some 

 brown, others rust-colored, some with soft, 

 others with coarse hair ; they differ also in the 

 length of the tail, and in having it more or less 



