J. E. DUKHDKN 159 



InhabiU pnicticnily tho wholo of tho sub-continent of South 

 Africa. 



Ob«H»rve<i alonpiido one another, im can now Im^ <lone at (JrcMitfrintein, 

 no one could fail to tiislin^uish \\\r nnrth<'rn from th«* Houthcrn ostrirh. 

 The greater height of the former, the stronger liinhH and th<' light 

 yellow of the skin an* obvious features, while the sexually nuiture cock 

 is still nion* distinctive on account of the brilliant scarlet of the head, 

 ni*ck and legs, and the red colour of the b(Mly generally. The naked 

 patch on the head and the smooth, larger eggs are just ;us consUmt dis- 

 tinguishing features. Many small differences of feather structure occur, 

 and are of much imj)ortance to the practical ostrich farmer. Hitherto 

 all the distinguishing characters of the imjK)rted northern ostrich have 

 been retained under the new conditions of South Africa and re-appear 

 in the progeny, showing that they are hereditary and inde{)endent of 

 climatic and other environmental influences. 



Whether the northern and the southern ostrich are to be regardei^i 

 as distinct species depends largely upon one's conception of the term 

 species and will be discussed later. It may be noted however that the 

 two are found to interbreed freely and reciprocally, and the crosses or 

 hybrids have also been proved to be fertile, both inter se and with either 

 of the parent forms ; at the same time the two races have many dis- 

 tinctive characters which are germinal in their origin. 



Nature of the Material. 



From a genetical point of view the material on which the investiga- 

 tions are being conducted is heterogeneous. The imported Nigerian 

 birds are such as were procured by the Arabs from wild nests, and then 

 reared in kraals for the sale of their plumage. Methodical ostrich 

 farming, as conducted in South Africa, is scarcely known in North 

 Africii, and chicks are not bred in captivity ; hence the birds are un- 

 influenced by any artificial selection. They exhibit much variation in 

 the details of feather structure, and many distinct commercial types of 

 plumes are represented, though all the birds come from one area. On 

 importation the greater number were chicks about six months old. 

 The majority of the older birds failed to become adapted to their new^ 

 environmental conditions, and many died from lack of iminunity to the 

 various parasitic diseiises affecting the southern bird. A selection has 

 been made of those producing the most desirable plumage and the 

 others discarded. 



