Permanence and Evolution. 49 



A 

 belongs to a land of droughts, occasionally 



reviving by reversion, and after some such 

 revival preserved in South America by me- 

 thodical selection. This may be found to throw 

 light on many instances of odd breeds character- 

 istic of places where they are not likely to be 

 indigenous, and specially on some we shall have 

 to deal with in treating of 



THE SHEEP. 



Of the origin of any of our domestic races 

 of sheep nothing is known. According to Blyth 

 (" Proceedings of Zoological Society of London," 

 Part viii. p. 62), there are about fourteen races 

 of wild sheep now living ; how many there may 

 once have been we do not know. Darwin men- 

 tions with a note of admiration that Anderson 

 supposes British sheep to be the descendants of 

 no less than eleven native wild forms, " with a 

 bold defiance of all that is known as to 

 geographical distribution ; " but if (as palseon- 



