ASSIMILATIVE COLOURATION. 467 
to the Spotted Deer, says, ‘‘ unless it moves, few beasts are more 
difficult to see; the colour of the skin harmonizes with the dead 
leaves and grass, while the white spots are indistinguishable from 
the little flecks of light caused by the sunshine passing through 
the leafy branches.” * These observations have the great merit 
of being neither the result of preconceived opinion, nor the effort 
to support a theory. Mr. Galton’s journey was made during the 
years 1850-2, before the advent of that epoch-making work the 
‘Origin of Species,’ which at once rivetted attention on all these 
phenomena. General Douglas Hamilton simply recorded the 
impressions of a sportsman with thirty-five years’ experience in 
India. Such testimony cannot be gainsaid, and though numerous 
other illustrations could readily be compiled, and from the pens 
of capable observers, those here given will suffice as regards the 
standard of competence and accuracy. On the other hand, I was 
surprised, in reading the ‘Travels and Adventures in South East 
Africa’ of that celebrated and experienced hunter, Mr. P. C. 
Selous, that he seemed to have no similar observations to record. 
In reference to the above instances of spots and stripes 
affording concealment, the explanation of ‘‘ active mimicry,” as 
I hope to advocate subsequently, might be applied; but then it 
must be remembered that the same phenomenon is found in 
other animals who live under very different conditions. Thus the 
Zebra Shark (Stegostoma tigrinum) is marked with black or brown 
transverse bars or round spots. Again, in Australia, according 
to Prof. Strong, the Rabbit is not only often parti-coloured, but 
numerous instances occur not only of white and black Rabbits, 
but of Rabbits “ with beautifully striped skins.” t 
The origin of spots and stripes is shrouded in obscurity. In 
domesticated animals, such as Dogs, Cats, cattle, and Horses, 
unsymmetrical markings constantly occur. According to Mr. 
Wallace, “‘Such markings never occur in wild races, or if they 
occur in individual cases they never increase; and I have given 
* Roy. Nat. Hist.,’ vol. ii. p. 8355.—Livingstone seems inclined to the 
opinion that such animals take refuge in the forest to escape from the 
hunters: ‘‘ But here, where they are killed by the arrows of the Balonda, 
they select for safety the densest forest, where the arrow cannot be easily 
shot” (‘ Missionary Travels and Researches in South Africa,’ p. 280). 
+ ‘ Zoologist,’ 3rd ser., vol. xvili. p. 406. 
