SOME "COLD-BLOODED" LOVERS 167 



yellowish flesh colour, with a conspicuous dark spot on 

 each of the gular pouches, which are extended to their 

 utmost. He stands upright, raising the forepart of the 

 body as high as possible, and nodding his head up and 

 down. As he does so the mouth is rapidly opened and 

 shut, but no sound is emitted. When he is driven away, 

 caught, or killed, the dark spot disappears entirely from 

 the neck." 



Normally sluggish, the Lizards display, it will have been 

 remarked, a quite surprising degree of animation when 

 maddened by mate-hunger. Some exhibit a considerable 

 degree of pugnacity. In Anolis carolinensis, for example, 

 when two males meet they face one another, bob the 

 head up and down two or three times, expand the throat 

 pouch, lash their tails from side to side, and then, worked 

 up to the requisite degree of fury, rush at one another, 

 rolling over and over and holding firmly with the teeth. 

 The conflict generally ends in one of the combatants 

 losing his tail, which is eaten by the victor. 



The Chamseleons include among their number species 

 which have developed quite formidable horns, recalling 

 those of the Rhinoceros or, better, of the extinct 

 Arsinoetherium, since they are placed side by side instead 

 of one behind the other. In Owen's Chamaeleon there 

 are three such horns, two on the forehead and a median 

 horn on the snout, and these are borne only by the 

 males. 



The marvellous play of colour which many Lizards 

 display is commonly attributed indifferently to " pro- 

 tective coloration " and to " sexual selection." It is 

 unlikely that both have played equally important parts 

 in their development. If the case of certain of the 

 Geckoes alone is taken, then there would seem to be no 



