72 THE NATURALIST IN AUSTRALIA. 



upon and kill other and larger lizards, such as Varani, refusing to come to close 

 quarters with so formidable-looking an object as Chlamydosaurus, when it turns upon 

 them with gaping mouth and suddenly erected frill. The erection of the feathers of 

 an owl or the fur of a cat is correlated with a like " scaring " function, but the 

 inflation of the hood of the Cobra, and in a less degree the neck-membranes of other 

 snakes, furnishes, perhaps, a more appropriate analogy. In one other Australian 

 species, Amphibolurus barbattts, commonly known as the Jew Lizard, which is also 

 figured and described in this Chapter, the throat membrane is likewise inflated under 

 the influence of irritation in such a manner as almost to constitute a frill. As 

 hereafter recorded, in fact, this species, in districts south of the habitat of 

 Chlamydosaurus, is commonly distinguished by the popular name of the Frilled 

 Lizard. 



It is worthy of note with reference to the elevation and depression of the 

 membranous frill of Chlamydosaurus that the species is not unfrequently delineated in 

 natural history works with this structure more or less fully extended, but with the 

 mouth completely closed. The author has also observed mounted specimens in 

 museums displaying a corresponding relationship of the organ and structure indicated. 

 As a matter of fact, the opening of the mouth and the erection of the frill are 

 synchronous actions which cannot be exercised independently of one another. An 

 explanation of this circumstance is afforded by the presence of slender processes of 

 the hyoid bone which extend on either side through the walls of the membranous 

 frill. The relative elevation of the frill is consequently in direct proportion with 

 the depression of the mandible, and it is only under the condition of the mouth 

 being opened to its widest extent that the frill is so conspicuously displayed as to 

 stand out at a right angle from the animal's neck, as indicated in several of the 

 accompanying illustrations. 



Although presenting so weird and formidable an appearance, the Frilled 

 Lizard possesses but feeble powers of aggression. Its teeth are small, the jaws 

 comparatively weak, and it is but rarely that the animal attempts to bite, relying 

 apparently on the discomfiture and retreat of its would-be assailants through the 

 terror-striking appearance of its gaping jaws and erected frill. Individual specimens 

 were, however, found by the author to differ materially in the exercise of their 

 defensive or aggressive proclivities. With the majority of some half-a-dozen examples 

 kept in confinement the non-aggressive form of defence was alone displayed. Two 

 exceptional individuals, however, manifested an essentially hostile and pugnacious 



