J. K. OlIKKDKN 191 



surface of the win^ is now pnicticully ujikrcJ. Only <»ni' row of under- 

 ooverte pt»raist8. ami it in hanlly ever complete, while rare HurvivaU of 

 members of the »eci»n(l and third rows indicnte that the under Hurface 

 was at one time well covertMl. The win^ (Hiills and up|M'r-covertH are 

 many le,H8 in number in some stniins than in oth<»rH, and th<* under 

 covering of down for the IhkIv generally hiis all but ilisjipjx'anMl, vestigial 

 plumules apiKMiring only around the base of th** large feathers of the 

 wing and tail. Pn>bably no bird is at present so naked lus the ostrich. 



It is cpiestionable however whether the loss of plumage hitherto has 

 any serious influenci^ on the well being of the ostrich. It is not incom- 

 patible with its present existence. But should the losses continue to 

 a much further degree the absence of a protective covering may begin 

 to be felt; while should the number of wing (juills become still further 

 lessened their inability to cover the usual quantity of eggs (12 to IG) 

 during incubation may aflfect the number of chicks reared. 



It is likewise impossible to Jiscribe any selection or utilitarian value 

 to the colour differences between the northern and the southern ostrich. 

 The light colour of the chicks, young birds and hens of the former com- 

 pared with the dark colour of the latter can hardly be reganled as either 

 advantageous or disadvantageous. The intense scarlet nuptial coloura- 

 tion of the northern cock as contrasted with the restricted scarlet of its 

 southern rival has already been shown to give it no preference in the 

 eyes of its sombre mate. On the natural veld it might i>ossibly add to 

 its conspicuousness, supposing any greater display value on the African 

 plains could be thought of than that of an ordinary cock with his intense 

 black body plumage, white wings, white neck and light legs'. 



In like manner the marked differences associated with the egg of 

 the two races can scarcely be deemed to have any adaptive value. The 

 bigger northern bird may be expected to produce a larger egg than 

 its smaller southern relative, but from a selection point of view nothing 

 in reason is to be said in favour of its rounder shape, smooth surface and 

 absence of pitting, in comparison with the more oval shape and pitted 

 surface of the other. Both are equally successful in artificial ;is well as 

 natural incubation. 



On mechanical grounds some advantage may accrue from the loss of 

 the fourth toe, the claw of which has almost disappeared from the race, 



* Ex-President Roosevelt in African Game Atiimals, has given much consideration 

 to the question of protective colouration and considers (p. 181) that " Cock ostriches 

 alwajs show jet black, and are visible at a greater distance than any of the common game; 

 the neutral tints of the hens making them far less conspicuous." 



