522 LACERTAE chap. 



hidden. The body is depressed, devoid of a dorsal crest ; on the 

 throat is a transverse fold but no sac. 



A. Zander^ has made interesting observations upon the habits 

 of several species. 



Ph. helioscopus lives on hard stretches of soil, which are 

 absolutelv bare of vegetation, the soil being baked as hard as a 

 paved road. The lizards live on any insects they can get hold 

 of, chiefly, however, upon mining ants. Wlien chased they run 

 with short jerks, carrying the tail high or rolled up. 



Fh. inter scapular is occurs, in Transcaspia, on the shifting, 

 loose sand. It runs so fast that one scarcely sees anything but 

 its shadow. Tlie tail is rolled upwards. With short jerks 

 it suddenly changes its direction, stops behind a few blades of 

 grass, or in the open, makes a few shaking, wavy movements, 

 and covers it.self lightly with sand. Shortly after that the top 

 of the head appears, the grains of sand rolling off between the 

 strong supraciliary ridges, and the little creature, only about 3 

 inches long, peeps out of its temporary hiding-place. 



Ph. mystaceus, which inhabits Transcaspia and parts of 

 Southern Russia, often faces its aggressor, raising itself upon its 

 fore-limbs, curling and uncurling its tail in its excitement, and 

 holding its mouth widely open. The creature, which attains a 

 length of 9 inches, inclusive of the long tail, then assumes a 

 markedly changed aspect. The flaps of skin at the corners of 

 the mouth swell up into a half-moon-shaped transverse plate, 

 the hinder surface of which is covered by the outer skin, while 

 the front is a continuation of the rosy lining of the mouth, 

 which thereby appears hugely enlarged. When biting it hangs 

 firmly on to the finger. This friglitening attitude is interest- 

 ing, since it occurs in a much more developed condition in the 

 foUowinij o;enus. 



Chhonydosaurus /./>////. — This peculiar Agamoid, which 

 inliabits Queensland and Northern and North-Western Australia, 

 is easily recognised by the large frill-shaped dermal expansion on 

 either side of tlie neck. The two halves are confluent on the 

 throat. The whole frill can l)e erected, and is worked by the 

 much-elongated arches or horns of the hyoid apparatus, which 

 extend into the flaps of skin, somewhat like the ribs of an 

 umbrella. The specially modified hyoidean nmscles spread out 



1 Zool. Garten. 1895, p. 2:>7. 



