222 MY SOMALI BOOK 



in which different species of the ungulata do associate 

 together on the most friendly terms. 



Again, the necessity of recognition marks to obviate 

 the danger of crossing between allied species is, as 

 Mr. Selous points out, largely illusory, at any rate 

 among the larger animals, for the simple reason that 

 the ranges of nearly allied species very seldom overlap, 

 and where such overlapping takes place, interbreeding 

 undoubtedly does at times occur. 



The black and white face marks of the oryx are an 

 instance of colouration that, like Mr. Selous, I have 



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found certainly not inconspicuous, in the bush or out 

 of it. They might doubtless be put down as aids to 

 recognition, if the oryx has any occasion for such — 

 that is what I doubt. 



There are, however, two occasions on which it is 

 easy to agree with Dr. Wallace that some means of 

 rapid recognition at a moderate distance would seem 

 likely to be of undoubted value. I mean in the case 

 of birds on migration, and in the case of a young 

 creature for whom it is a necessity to keep in close 

 touch with its parent or with the flock. Many of the 

 markings on the wings of birds are no doubt correctly 



