1909.] ON THE DIFFERBXTIATION OF ZEBRAS. 547 



The following papers were read : — 



1. Contributions to the Study o£ the Equidse ; i. The 

 Differentiation o£ the Three Species oi: Zebras. By 

 Prof. William Ridge way, M.A., Sc.D., F.B.A., 

 LL.D., Litt.D.* 



[Received April 21, 1909.] 



(Text-figures 140-155.) 



I propose to describe ten skins of Zebras from British East 

 Africa, the interest of which consists partly in the fact that they 

 were all shot expressly for me, and that an exact record of the 

 locality and the altitude was kept in each case. They have thus 

 a far higher scientific value than the ordinary specimens in our 

 museums, which have for the most part been obtained from 

 sportsmen or traders, who could give no accurate information 

 regarding the provenance of the specimens. I must express my 

 gratitude to the Rt. Hon. Alfred Lyttelton, K.C., M.P., who 

 when Secretary of State for the Colonies authorised the officials 

 of British East Africa to assist me in obtaining zebra skins, and 

 to my friend, Mr. 0. W. Hobley, C.M.G., Assistant-Commissioner 

 at Nairobi, who kindly undertook to see that the instructions of 

 the Secretary of State were carried out, and on whom devolved 

 all the trouble of packing and despatching the specimens. 



But the skins have a further value, since they demonstrate 

 that the individuals of the same species vary in coloration from 

 locality to locality, and that it is useless attempting to make 

 species or subspecies out of animals which are mere local varieties. 

 Finally, we may reason from what these skins demonstrate as 

 taking place in a given area that the same diflferentiation has 

 taken place in the coloration of all the Equidse from Northern 

 Europe and Asia down to Cape Colony, a lesson which applies 

 equally to the whole animal kingdom, man included. 



Zooloo"ists are generally agreed that all existing Zebras fall into 

 three main species : — Equus zebra, or the Mountain Zebra,;f ormerly 

 very abundant in Cape Colony, E. hitrchelli, and E. grevyi, though 

 Dr. Matschie treats as true species certain varieties of the 

 Burchell family. Mr. Pocock has shown that all the varieties of 

 the Burchell Zebra seem to shade off into the better marked 

 specimens of the now extinct Quagga of Cape Colony, whilst 

 Prof. Ewart has shown that a bridge can be found between the 

 Mountain Zebra and the Burchelline family, through Crawshay's 

 variety of the latter. 



The chief characteristics of the three species may be briefly 

 enumerated. 



The splendid Grevy Zebra, found in Somaliland, Shoa, and 



* Commuuicated bv Dr. P. Chalmeks Mitchell, M.A., F.R.S., F.Z.S. 



38* 



