XI 
THE COLOURS OF AMPHIBIANS 
235 
The effect of light on the developing larvae was 
also tested, and it was found that light has but little 
effect, though on the whole the larvae are darker in 
light than in darkness. This is interesting because 
the same thing has been noticed in tadpoles of the 
frog, which become pale and transparent in darkness, 
while adult frogs, many fishes, reptiles, etc., become 
pale in strong light. Thus at least in the frog the 
larva and the adult react differently to the stimulus 
of light. 
As an interesting commentary upon these obser¬ 
vations of Fischers, we may note that Bedriaga in 
describing the larvae of Molge aspersa, remarks that 
while the colour is usually an olive-brown with 
yellowish spots, larvae taken from deep water are 
much darker in tint, and the yellow spots are reduced 
both in size and intensity. On the other hand, 
larvae from sunny shallow situations are pale in 
colour and very distinctly spotted with yellow. As 
Fischel found that light as a whole tended to darken 
the colours, we must suppose that in this case it is 
the temperature of the water in the two situations 
which is important in affecting coloration. 
Similarly, Karl Knauthe found that adult Am¬ 
phibians (Bufo variabilis and B. vulgaris, Pelobates 
fuscus, and others) turned dark, often gray or black, 
when exposed to the influence of intense cold. It 
would appear from this observation that the larvae 
and adults react similarly to variations in temperature. 
