158 EXPERIMENTAL EVOLUTION LECT. 



species we add some fifteen or eighteen species which 

 are more or less domesticated by the inhabitants of 

 other parts of the world, we obtain a sum total of 

 some forty, let us say fifty species. 



The wild forms of these domestic species are 

 nearly all known and living. The two genera of 

 ostriches, found in Africa and America, are among the 

 most recently domesticated forms, and in fact have 

 been domesticated only to a slight extent. Wild 

 swans are yet found in Sweden and Norway ; geese 

 are met in Asia and Europe ; ducks are found in the 

 greater part of Europe ; the turkey is an inhabitant 

 of the New World, whence it was imported but a few 

 centuries ago ; pheasants but yet partly domesticated 

 live wild in Central Asia ; the guinea-fowl has been 

 found wild in Africa by De Brazza ; the peacock 

 inhabits India, Java, and Sumatra ; the common fowl 

 is the descendant of the Indian Callus Bankiva ; the 

 rock-pigeon is the ancestor of all our varieties of 

 domestic pigeon. 



However, wild guinea-pigs are no longer found in 

 South America, where they existed some centuries 

 ago ; and of our hog only doubtful ancestors exist in 

 Asia and the Sunda Islands (Sus vittatus and papu- 

 ensis). Wild horses most probably still exist. Pliny, 

 Varro, Strabo mention them, and Erasmus Stella 

 and Rosslin speak of wild horses in 1518 and 



