THE ORIGIN OF SPECIES. 45 



greyhounds by careful and methodical selection, or by that un- 

 conscious selection which results from each man trying to keep 

 the best dogs without any thought of modifying the breed. 



"Even without any change in the proportional numbers of 

 the animals on which our wolf preyed, a cub might be born 

 with an innate tendency to pursue certain kinds of prey. Nor 

 can this be thought very improbable; for we often observe 

 great differences in the natural tendencies of our domestic ani- 

 mals: one cat, for instance, taking to catching rats, another 

 mice; one cat, according to Mr. St. John, bringing home winged 

 game, another hares or rabbits, and another hunting on marshy 

 ground, and almost nightly catching woodcocks or snipes. The 

 tendency to catch rats rather than mice is known to be inher- 

 ited. Now, if any slight innate change of habit or of structure 

 benefited an individual wolf, it would have the best chance of 

 surviving and of leaving offspring. Some of its young would 

 probably inherit the same habits or structure, and by the repe- 

 tition of this process a new variety might be formed which 

 would either supplant or coexist with the parent-form of wolf. 

 Or, again, the wolves inhabiting a mountainous district, and 

 those frequenting the lowlands, would naturally be forced to hunt 

 different prey ; and from a continued preservation of the indi- 

 viduals best fitted for the two sites, two varieties might slowly 

 be formed. These varieties would cross and blend where they 

 met; but to this subject of intercrossing we shall soon have to 

 return. I may add that, according to Mr. Pierce, there are two 

 varieties of the wolf inhabiting the Catskill Mountains in the 

 United States, one with a light greyhound-like form, which pur- 

 sues deer, and the other more bulky, with shorter legs, which 

 more frequently attacks the shepherd's flock." (pp. 90, 91.) 



We eke out the illustration here with a counterpart 

 instance, viz., the remark of Dr. Bachman that " the 

 deer that reside permanently in the swamps of Caro- 

 lina are taller and Ipngeivlegged than those in the 

 higher grounds." l 



' " Quadrupeds of America," vol. ii., p. 289. 



