222 



KNOWLEDGE, 



[October. 1902. 



tho ininiiitaitis of Capo Colony and adjacent districts. 

 Nortli of tlic Vaal lliver the veldt was, however, dotted over 

 with herds i)f Biirchell's zebra, the aforesaid bonte-quagfja, 

 which (inclusive) of its local races, has a verv extensive 

 geographical distribution in East and Central Africa. It 

 is scarcely necessary to say tiiat this species differed from 

 the true quagga in having the whole body striped, as 

 well as by its much more brilliant type of colouration and 

 the pattern of the striping. One very remarkable feature 

 in connection with this species must not be passed over 

 without notice. In the original and typical race (now 

 apparently extinct), which was obtained just north of the 

 Vaal Kiver, in British Bcchuanaland, and therefore imme- 

 diately adjacent to the northern limits of the quagga, the 

 whole of the legs, as well as a considerable portion of the 

 hind-quarters, were devoid of stripes. In this respect the 

 ty[iical form of the Transvaal species came much nearer to 

 the last-mentioned animal than do the races from more 

 northern districts, in which the hind-quarters and legs are 

 more or less com])letely striped ; the striping attaining its 

 fullest development in the most northern race of all, the 

 so-called Grant's zebra of Somaliland and Abyssinia. 



Of course, these gradations towards the quagga-type 

 of colouration of the more southern representatives of 

 Burchell's zebra, as well as the difference in the colouration 

 of the quagga itself as compared with zebras, have a 

 meaning and a reason, if only they could be discovered. 

 And it may be remarked incidentally iu this place that 

 unless we attem]>t to account rationally for such variations 

 there is little justification for the modern practice of 

 distinguishing between the local races of vaiiable species. 



The striping of the zebras, which there is considerable 

 cause for regarding as the primitive type of colouration of 

 the horse family in general, is evidently of a protective 

 nature. It was stated some years ago that zebras a short 

 distance off are absolutely invisible in bright moonlight, 

 and I have reason to believe that the same is to a great 

 extent the ease in sunlight. For some reason or other the 

 species inhabiting the plains (not the mountains, be it 

 observed) of South Africa have tended to discard this 

 striped colouration, the southern race of Burchell's zebra 

 exhibiting the first, and the quagga the second stage in 

 this transformation. In North Africa the transformation 

 has been carried a stage further, the wild asses of the Red 

 Sea littoral having discarded their stripes almost com- 

 pletely in favoui- of a uniform grey or tawny livery. In 

 this part of the continent there is now no trace of a 

 transitional form, whatever may have been the case in the 

 past, and we thus have the sharp contrast between the 

 uniformly coloured wild asses of the coast of the Red Sea 

 on the one hand, and the fully striped zebras of Abyssinia 

 and Southern Somaliland on the other. 



Whether there is anything in the climatic and other 

 physical conditions of the jdains of Cape Colony which 

 renders a partially .striped species less conspicuous than 

 (me in which the striping is fully developed, the dis- 

 apjjearance of the quagga makes it now impossible to 

 determine. But observation might advantageously be 

 directed to the comparative invisibility, or otherwise, of 

 the wild asses of the Red Scu littoial and the fully striped 

 zebras of the interior, and whether this would !"■ affected 

 in any degree by the transference of the one to the habitat 

 of the other. Whatever be the explanation, the tact 

 remains that at the opposite extremities of Africa some of 

 the memlx>rs of the equine tribe have developed a tendency 

 to the repliicement of a strij^ed livery by one of a uniform 

 and sober hue, and that in the south of the continent this 

 tendency exists only in the species inhabiting the jilains. 

 Moreover, it is only in S(.)uth Africa that the ti'ansitional 



form is met with, and only in the north of the continent 

 that the striping has l)een completely lost. 



But this is only one phase of a general tendency among 

 mammals to replace their spots or stripes by a uniformly 

 coloured coat, as is exemplified by the c'ase of many deer, 

 pigs, and tapirs, as well as by the lion and the puma 

 among the Carnivora. 



So far as I am aware, no one has ever attempted to give 

 a philosophical reason for this nanarkable tendency. But 

 till an adequate explanation of the phenomenon be forth- 

 coming, naturalists, to repeat the words of a well-known 

 ornithologist, have left half their work (and I am inclined 

 to think the more important half; undone. Without 

 ascertaining the reason for phenomena of this nature our 

 zoological work is, indeed, as though a man were content 

 with describing the mechanism of a complicated machine 

 without an inkling as to its use. 



One word more, and I have done. To the systematic 

 zoologist, the quagga is an animal of special interest as 

 affording evidence of the intimate relationship between 

 the zebras and the wild asses. Although, judging from 

 its geographical distribution and its physical character- 

 istics, it was probably not the actual transitional form 

 between the striped and the uniformly coloured species, 

 yet it serves to show the manner in which the transition 

 was effected. In this sense it is undoubtedly a link, and 

 since it is now, unhappily, missing from the roll of living 

 animals, the reason for the title of the present article will 

 be apparent. 



♦ 



ACROSS RUSSIAN LAPLAND IN SEARCH OF 

 BIRDS. 



By Harry F. Witherby, f.z.s., m.b.o.u. 



IV.— IN THE BIRCH SCRUB AND ON THE 

 ROCKY COAST. 



The concluding portion of my last article* found my 

 companion and mvself amongst the marshes near the 

 northern end of the great Imandra Lake. 



Our limited food supply continually drove us forward, 

 so that however interesting a place might be we could 

 never afford to stay there long. Rowing to the head of 

 the Imandra, we landed at the mouth of a small river 

 which flowed into the lake. The river was full of rapids, 

 and could not be ascended by a boat, so we walked across 

 country to a little lake, which the river connected with 

 the Imandra. 



Crossing this lake — the Pereyaver — we arrived at an 

 interesting water ]5artiiig. An almost level strip of land 

 of only some five hundred yards across separated two 

 chains of lakes and rivers — the one up which we had 

 travelled flowed southward and reached the White Sea, 

 while the other rushed northward and found an outlet in 

 the Arctic Ocean. 



At this spot we were attacked by vast swarms of 

 blood-sucking flies, so small that they easily passed througb 

 the mosquitoe veils, and so voracious and poisonous that 

 we were soon sufi'ering from swollen glands and intense 

 ear-ache. We were forced to pack up and flee northwards, 

 camping eventually on the shores of the Pulozero. Here 

 we found unexpected civilization in the shape of a well- 

 built telegraph station, inhabited by a most hospitable 

 official, who treated us with every kindness. Although 

 somewhat short of flour himself, he provided us with 

 bread, which we sorely needed, and in the way of luxuries 

 he had his bath house heated and })repared for our use. 



• Set Kkowi-edok, June, 1902. 



