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); 

 M from 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 thecat.Thediffe- 

 ,,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 Rutimeyer 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. 



