436 



LOWER VERTEBRATES. 



Stout nails, are too small to allow the animal any very rapid movements, the chief 

 source of protection being in the hard, thick tuberculate shields which cover the 

 entire upper side of the body, though below they become thin and smooth. About 

 this strange animal's habits but little is known. It has been captured in western 

 Australia. 



The family Geeehosaueid^ includes but a single genus. Gerrhosaurus Jlavigu- 

 laris is a slender lizard, inhabiting South Africa, of about twelve inches in length, 

 and colored above with yellowish-brown, striped and banded with lighter and darker 

 shades. Localities covered with a thick growth of underwood seem to be the most 

 often chosen, the animals, on apprehending danger, concealing themselves by burrow- 

 ing under the dead leaves or loose earth. Specimens are distributed over a wide area. 



Rw 



rfV^.n, 



Fig. 252- — Trachysaurus nigosus. 



from Cape Colony as far north as the Tropic of Capricorn. G. bibroni inhabits the 

 shaded ravines of the Orange River, while G. typicus prefers the dvj plains, over the 

 sand of which they scamper with most extraordinary rapidity, it being almost impos- 

 sible for the eye to follow them in their flight. They are also active burrowers, and, 

 on being disturbed, often conceal themselves in the loose sand, though only to a mode- 

 rate depth. 



ScnsroiD^ includes a large number of terrestrial lizards inhabiting the more tropi- 

 cal countries generally, and protected by a covering of smooth bony plates, which, on 

 the crown, are regularly arranged, like those of serpents. Skinks are found secreted 

 under old logs, bark, and dead leaves, or in shallow burrows in loose earth. They 

 are oviparous, and the eggs, to the number of ten or a dozen, are hid away in those 

 situations. 



