4O Permanence and Evolution. 



teristics are permanent when the strain is kept 

 pure. 



CATTLE. 



Here, as usual, earlier naturalists supposed 

 only one domestic ox Bos Taurus of which 

 the Lithuanian bison, or so-called aurochs, was 

 generally supposed to be the original stock ; 

 the American bison to be a climatal variety of 

 the same. Cuvier pointed out the fundamental 

 differences between the domestic ox and both 

 European and American bisons ; but all kinds 

 of domestic ox, humped and non-humped, were 

 still generally considered variations of one stock. 

 Lately, Blyth (apud Darwin, " Animals and 

 Plants," 2nd Edition, vol. i. p. 83, also " Land 

 and Water," vol. iv. p. 10) from the point of 

 view of a descriptive naturalist, and Riitimeyer 

 (" Der Linnesche Genus Bos ") as an anatomist, 

 have pointed out such essential distinctions 

 between the humped and non-humped cow, 



