320 



EVOLUTION AND ANIMAL LIFE 



miles, he finds himself at Hakodate, in Japan. He is now separated 

 from his starting point by an almost endless succession of plains and 

 mountains, arid deserts or icy plateaus; yet, when he visits the interior 



FIG. 187. Three species of jack rabbits differing in size, color, and markings, but be- 

 lieved to be derived from one stock. The differences have arisen through isolation 

 and adaptation. The upper figure shows the head and fore legs of the black jack 

 rabbit, Lepus insulariis, of Espiritu Sanctu Island, Gulf of California; the lower 

 right-hand figure the Arizona jack rabbit, Lepus alleni, specimen from Fort Lowell, 

 Arizona; and the lower left-hand figure the San Pedro Martin jack rabbit, Lepus 

 martirensis, from San Pedro Martin, Baja California. 



