88 REPTILES 



and the moloch {Moloch horridus). In the former the resem- 

 blance to dark-coloured soil is striking ; the skin being slaty 

 grey with flecks of white and black. On the other hand, the 

 moloch is coloured to harmonise with sandy soil containing 

 brown pebbles or fragments of stone ; the ground-colour being 

 buff, with a number of oval cholocate blotches. When half- 

 buried in soil of the above description, the creature must be 

 practically invisible ; the illusion being enhanced by the 

 horn-like excrescences dotted over the head, body, and tail. 



It is, however, by no means only such dull-coloured lizards 

 that harmonise in hue with their surroundings. Few creatures 

 are more brilliantly coloured than the eyed lizard {Lacerta 

 occllata) of Southern Europe, with its back of mingled flecks of 

 gold and chocolate, the large bright blue " eyes " on the flanks 

 and the brown head and tail. And yet there can be little doubt 

 that these harlequin colours fade into a confused blue when this 

 reptile is lurking among grass and other low herbage. Again, 

 certain small snakes have their skins mottled with bright red 

 and black ; a combination which although conspicuous in cap- 

 tured specimens, harmonises with soil composed of red sand 

 mingled with dark pebbles. A similar type of coloration occurs 

 in that American reptile known as the poisonous lizard, or gila 

 monster (Helodenna suspectum), which is not uncommon in 

 parts of Arizona and the neighbouring districts. If this reptile 

 inhabit country with a soil of the above-mentioned description, 

 its colouring must be of a protective nature, but such descriptions 

 of its habitat as have come under my notice are silent on this 

 point. On the other hand, the gila monster may present an 

 example of " warning colour" ; that is to say, its bright colour- 

 ing may be conspicuous and serve to warn enemies (by inherited 

 experience) of its dangerous and poisonous nature. 



In concluding this part of the subject, it may be pointed 

 out that no reptiles display that peculiar protective arrange- 

 ment of colouring so commonly developed in large mammals 

 living in the open, which consists in having the under-parts 

 light and the back dark, thus neutralising the effect of the 

 shade cast by the body. And the explanation of this is not 

 far to seek, for no existing reptiles have the body sufficiently 

 elevated above the ground to make this type of coloration 

 effective. It is not meant by this to assert that no reptiles 



