104 THE EVOLUTION OF LIVING BEINGS. 



Domestic dogs. 



Vol. I, p. 26 : ,,it is highly probable that the domes- 

 tic dogs of the world are descended from two well- 

 ,,defined species of wolf (viz C. lupus and C. latrans) 

 ,,and from two or three doubtfull species (namely the 

 ,,European, Indian and North African Wolves); 

 ^frorn at least one or two South American canine spe- 

 ,,cies; from several races or species of jackal, and per 

 ,,haps from one or more extinct species". 



Domestic Cats. 



Vol. I, p. 49. ,,we have seen that distant countries 

 ,,possess distinct domestic races of the cat. The diff e- 

 ,,rences may in part be due to descent from several 

 ,,original species, or at least from crosses with them". 



Domestic Horses. 



Vol. I, p. 53. Whether the whole amount of diffe- 

 ,,rence between the various breeds has arisen under 

 ,,domestication is doubtfull. From the fertility of the 

 ,,most distinct breeds, when crossed, naturalists 

 ,,have generally looked at all the breeds as having 

 ,,descended from a single species. Few will agree with 

 ,,Colonel H. Smith, who believes that they have des- 

 ,,cended from no less than five primitive and diffe- 

 ,,rently coloured stocks. But as several species and 

 ,,varieties of the horse existed during the later ter- 

 tiary periods and as Riitimeyer found differences in 

 ,,the size and form of the skull in the earliest known 

 ,,domesticated horses, we ought not to feel sure 

 that ,,all our horses are descended from a single 

 species". 



The ass. 



