(;583 ) 



NOTES ON THE SPECIMENS OF WILD ASSES IN 

 ENGLISH COLLECTIONS. 



BY E. LYDEKKER. 



(Plates XVII.— XX.) 



THE gift to the British Museum by Mr. N. 0. Rothschild of the skeleton and 

 mounted skin of a wild ass (No. 59), collected by himself and Messrs. 

 Henley and Wollaston at Nakheila, Atbara River, Eastern Sudan, on February KJth, 

 1904, affords an opportunity of reviewing the state of our knowledge with regard to 

 the species and races of the wild asses of both Africa and Asia. Unfortunately, 

 owing to the lack of a sufficiency of specimens and of definite information with 

 regard to the place of origin of several of the few available examples, such a 

 review cannot be regarded as anything like final or complete ; several points in 

 regard to nomenclature and affinities being left for future determination. The 

 plan followed has been to review such of the more recent descriptions of these 

 animals as appear the most trustworthy, and to give coloured figures of specimens 

 in the museums and menageries in this country. Of the two races here included 

 under the specific title of Equus hemionus coloured figures have already appeared 

 in a paper recently contributed by myself to the Zoological Society's Proceedings ; 

 and it has therefore been considered unnecessary to repeat figures of these forms 

 in the present article. 



Apart from the question of species and subspecies, wild asses have an interest 

 from another point of view — namely coloration. In an article originally published 

 in the /e'e^fl? newspaper, but reprinted in my volume entitled " Mostly Mammals,'' 

 and in a later article which appeared in the Field for October 17th, 1903, I have 

 pointed out that a large number of mammals change their colour from rufous in 

 summer to grey in winter,* and I have also endeavoured to show that such colour- 

 changes are in the main confined to extra-tropical species. Excellent examples of 

 this type of colour-change are afforded by the European roe-deer, the North 

 American white-tailed deer, and the fallow-deer ; while the muntjac and the Indian 

 chital may be cited as examples of tropical species which undergo no seasonal 

 change of colour. 



The wild asses of the extra-tropical countries conform, in greater or less degree, 

 to both the above laws ; such colour-changes as take place being from rufous in 

 summer to grey-fawn in winter. The most marked instance of this type of change 

 being presented by the form described below as Equus onager castaneus. On the 

 other hand, the African wild asses, which are the only members of the group 

 found within the tropics, exhibit no seasonal colour-change ; their tint being at all 

 times of the year grey-fawn, which we may perhaps venture to assume is better 

 suited to their surroundings than sandy or rufous. 



The remarkable feature in connection with the conformity of colour-change iu 

 the non-tropical species of wild asses to that which obtains in the roebuck and the 



' By an unfortunate oversight, on p.ige 24 of " Mostly Mammals " the red is said to he the winter, 

 and the grey-fawn the summer colour. 



