XI 
THE COLOURS OF AMPHIBIANS 
229 
factors in coloration, the epidermic pigment having 
relatively little effect. In the larva, the dermis over 
its whole area contains both black and yellow cells, 
but the latter are more abundant at certain regions, 
corresponding to the future yellow spots of the adult. 
The peritoneum contains also both yellow and black 
cells, while in the adult there is no trace of yellow 
cells in it. 
Fischel’s observations on the coloration were made 
in connection with some experiments on artificially 
produced colour-change, and he did not therefore 
carry them beyond this point. Before proceeding, 
however, to consider the theoretical bearing of the 
facts given above, we may supplement them by some 
notes made by Dr. Bedriaga on the development of 
colour in the larvae of newts. Bedriaga did not 
investigate the histology of his specimens, but in 
view of the similarity of colour, we are probably 
justified in applying Fischel’s statements throughout. 
We may take the case of Molge montana , which 
is described in some detail, as typical of one set. In 
this form, larvae 10-15 mm - i n length are uniformly 
yellow beneath, and yellowish-white with black spots 
above. Larvae 20-25 mm. in length show these 
black spots spreading over the light ground, especially 
on the upper surface. From 25 up to 40 mm. the 
larvae show a gradual increase of the black pigment 
which now becomes the ground colour, the light pig¬ 
ment appearing in the shape of small spots, but 
forming also a median yellow stripe. Larvae of 40- 
45 mm. length appear when taken from deep water 
to be perfectly black, but if placed in shallow vessels 
they become much lighter, and then exhibit very 
