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SOUTH AFEICA 
distinguishable. The neck and belly did not appear to change 
colour. 
It was then killed, being rapidly overcome by chloroform, then 
becoming more dusky than I had seen it previously: that is to say 
it assumed its darkest coloration. 
Chamaeleon dilepis, Leach. The animal, a female, was taken 
near the Waterworks, Bulawayo, September 9th, 1905 (about 3 to 4 feet 
from the ground), on a shrub of Dombeya (?) rotundifolia, the white 
flowers of which were attracting a number of insects of various 
orders. I was startled on detecting the animal, which at first escaped 
my notice. 
Description .—Pale yellowish-grey, legs and tail darker; streaked 
and blotched with greenish-grey. Throat with six cadmium-yellow 
stripes. A yellow spot behind the shoulder, another over the ribs, 
and a yellow lateral line. 
It gave vent to a gurgling hiss when disturbed, and once bit me, 
but not hard enough to hurt. 
It was kept alive and observed at Victoria Falls, September 16th, 
1905. Placed on a plant of young Acacia, the animal soon lost all its 
darker bands and became almost uniform grey-green, with the above 
yellow markings. In the sun it became strongly mottled, with some 
tendency to be paler on the shady side, but this was not very marked. 
Its excrement consisted of elytra and other insect-fragments. 
When chloroformed, it became a uniform pale yellowish colour, 
a little paler than my khaki coat; that is to say, assumed its palest 
coloration. 
The moment that I saw the green Chamaeleon turn dark on the 
side towards the sun (a quite unexpected phenomenon) Mr. Abbott 
H. Thayer’s model of the Wild-duck in the Oxford Museum came to 
my mind. Here, I thought, was a striking instance of the principle 
of counter-shading, whereby shadow is annihilated and with it the 
conception of solidity. 
The dissimilar action of chloroform on the two reptiles is remark¬ 
able. If it be assumed (as seems likely) that the darkening of the 
green chamaeleon was paralytic, then the blanching of the grey 
chamaeleon must have been the result of stimulation, or vice versa. 1 
1 These observations, together with others of his own, generally concordant with 
mine, were communicated to the Linnean Society by Professor E. B. Poulton, 
F.B.S. Journal Linnean Society , Zoology , vol. xxx., 1907, pp. 45-48. 
