AGAMIDAE 



523 



and fold the frill. When this curious creature is pursued it folds 

 the frill and runs in a semi-erect position upon its hind-limbs, 

 with its fore-limbs hanging down. However, it cannot keep 

 up this peculiar gait for long, and it then suddenly turns to bay, 

 frequently at the root of a tree, which it can climb with ease. 

 When standing at bay it spreads out the shield to its full extent, 

 in the middle of which appears the widely opened mouth, which 

 is red inside and armed with powerful teeth. Altogether this 





Fig. 126. — Ohlamydosaurus kingi. x|. 



lizard presents a formidable aspect, and is an enemy not to be 

 despised, considering that it is strongly built and grows to nearly 

 3 feet in length. For a further account of the habits and of 

 the mechanism of the frill see De Vis.^ 



PhysignatJius. — This is a water-loving genus, inhabiting well- 

 watered districts with luxurious vegetation in Australia, Papuasia, 

 Siam, and Cochin China. The body and the very long tail are 

 laterally compressed and furnished with a low, serrated crest. 

 Ph. lesueuri of Queensland reaches a length of about 1 8 inches. 

 The general colour is dark olive above, with darker and lighter 



1 P. Linn. Hoc. N.S. W. viii. 1883, p. 300. , 



