594 Mr. Hans Gadow on Colour in Amphibia. [April 26, 



to, but there are many cases which seem to show that whatever has 

 produced the pattern has been au external influence. For instance, 

 in the common grass-frog the series of spots on the flanks extend 

 right across the folded limb, over the thighs, shanks and feet. They 

 form longitudinal bands only whilst the frog is at rest. When it 

 stretches the limbs the bands are disconnected, and wherever the 

 opposed parts touch and hide each other, there is no special pigmenta- 

 tion. This is a very common arrangement in Frogs. Again, there 

 are cases in which coloured lines go right across the eye, or, what 

 is still more puzzling, right across the gape of the mouth, as, for 

 instance, in the Argentine Toad (Ceratophrys ornata). This ugly- 

 shaped creature has a beautifully coloured carpet-like pattern of 

 black and yellow, with green patches. Each patch is surrounded by 

 a narrow line of white or yellow dots interspersed with lines of rusty 

 red and brown. Many of the spots look exactly like the little sun- 

 images which sunlight throws upon the ground when streaming 

 through dense foliage. The toad buries itself half in the soil, pre- 

 ferably in grass or under dense vegetation. If there is not enough 

 green it throws little lumps of soil upon its back, the skin of which 

 at the same time becomes more crinkled and assumes duller tones. 



[H. G.] 



