3 o2 AMPHIBIA xii. 5- 



makes them very difficult to see among the leaves; on the other hand, 

 R. temporaria and other species living among grass show a pattern of 

 dark marks, which breaks up their outline. In other amphibians, how- 

 ever, the colour makes the animal 

 conspicuous, for instance the 

 black and yellow markings of 

 Salamandra maculosa. Conspi- 

 cuous colour is often associated 

 with great development of the 

 poisonous parotoid glands and 

 is therefore presumably sematic 

 or warning coloration, allowing 

 recognition by possible attackers. 

 This correlation is not always 

 found, however; the toad Cera- 

 tophrysamericanaisd\i\\co\o\irtd 

 but poisonous, whereas C. dor- 

 sata has a bright pattern but is 

 harmless. 



Many frogs make a sudden 

 exposure of brightly coloured 

 patches on the thighs when they 

 jump. This presumably serves 

 to startle the attacker and such 

 colours may be called dymantic 

 or startling. A similar use of 

 colour is made by the cuttle- 

 fish (Sepia), which may suddenly 

 produce two black spots when 

 alarmed, and also by some Lepi- 

 doptera. It is interesting that the 

 colour used in this way so often 

 takes the form of black spots 

 ('eye-spots'), which have an es- 

 pecially striking quality. In some anurans these colours are irregular 

 dark marks, but in Mantipus ocellatus they take the form of definite 

 'eye-spots'. 



It must not be forgotten that the presence of pigment serves to 

 protect the organs from the effects of light, which may cause contrac- 

 tion when it falls directly upon muscles. Dark colour may also assist 

 in the absorption of heat, both in the adults and in the eggs. 



(a) (b) 



Fig. 175. Record of the movements of 

 Ambystoma walking on a smoked drum, 

 a, in rapid locomotion (with the body on 

 the ground); b, in slow locomotion (raised 

 up on the legs). (From Evans, Anat. Rec. 

 95.) 



