rBESIDENTIAL ADDRESS. 835 



Abyssinia by being greyer in colour, by tlie entire absence of shoulder stripes, 

 and by smaller ears^ in all which characteristics it comes closer to its neighbours 

 on the Asiatic side than it does to its relations iu Abyssinia and Nubia. 



Next we meet the zebras. First couies the magnificent Gr^vy zebra of Somali- 

 land, Shoa, and British East Africa. It is completely striped down to its hoofs, 

 but the coloration of the specimens from Shoa differs from that of those from 

 Somalilaud, and from those of British East Africa. The Grevy zebra has its hoofs 

 rounded in front like those of a horse, but its ears are more like its neighbours the 

 asses than those of any other zebra. 



In the region north of the river Tana the Burchelline group of zebras overlaps 

 the Grevy, and though it differs essentially in form, habits, and shape of it** hoofs 

 from the Grevy some of those in the neighbourhood of Lake Barringo show grid- 

 iron markings on the croup like those on the GrtSvy zebra, whilst, like the latter, 

 they also possess functional premolars. 



All the zebras of the equatorial regions are striped to the hoofs, but when we 

 reach the Transvaal, the Burchelline zebra, known as Chapman's, is divesting itself 

 of stripes on its legs, whilst the ground colour is getting less white and the stripes 

 less black. Further south the true Burchell zebra of the Orange River has com- 

 pletely lost the stripes ou its legs and under-surface, its general colouring being 

 pale yellowish brown, the stripes being dark brown or nearly black. South of the 

 Orange River the now extinct quagga of Cape Colony had not only begun to lose the 

 stripes of its under-part and on the hind -quarters, but in Darnell's specimen they 

 only survived on the neck as far as the withers, the animal having its upper surface 

 bay and a tail like that of a horse, whilst all specimens of quagga show a rounded 

 hoof like that of a horse. 



In the quagga of 30° to 32° S. we have practically a bay horse corresponding 

 to the bay Libyan horse of lat. 30°-32° N. 



But the production of such variations iu colour do not require great differences 

 in latitude. On the contrary, from a study of a series of skins of zebras shot for 

 me in British East Africa, each of which is from a known locality and from a 

 known altitude, there can be no doubt that such variations in colour are found 

 from district to district within a comparatively small area. 



In addition to the two species of zebra already mentioned, there is the moun- 

 tain zebra, formerly extremely common in the mountainous parts of Cape Colony 

 and Natal, though now nearly extinct in that area. Its hind legs, as miglit natu- 

 rally have been expected from its habitat, are more developed than those of the 

 other zebras, just as these same limbs are also more developed in the kiang of the 

 Himalayas than in any other ass. 



"With these facts before us, there can be no doubt that environment is a most 

 potent factor not only in coloration, but also in osteology. No less certain is it 

 that environment is capable of producing changes in animal types with great 

 rapidity. Thus, although it is an historical fact that there were no horses in Java 

 in 1346, and it is known that the ponies now there are descended from those 

 brought in by the Arabs, yet within five centuries there has arisen a race of ponies 

 (often striped) some of which are not more than two feet high. Darwin himself 

 has given other examples of the rapid change in structure of horses when 

 transferred from one environment to another, as for instance when Pampas horses 

 are brought up into the Andes. 



Another good example is that of the now familiar Basuto ponies. Up to 1846 

 the Basutos did not possess a single horse, those of them who went down and 

 worked for the Boers of the Orange River usually taking their pay in cattle. At 

 the date mentioned some of them began to take horses instead. These horses 

 were of the ordinary mixed colonial kinds, and we may be sure that the Boers did 

 not let the Basutos have picked specimens. The Basutos turned these horses out 

 on their mountains, where living under perfectly natural conditions their posterity 

 •within less than forty years had settled down into a well-defined type of mountain 

 pony. 



Nor is it only in the horse family that we meet with examples of the force of 

 environment. The tiger extends fi-om the Indian Ocean, through China up to 



3 H 2 



