88 THE STORY OF REPTILE LIFE. 



blotting paper. The similarity between the 

 moloch and horned "toads," it is to be re- 

 marked, is the result, not of blood relationship, 

 but of adaptation to a similar environment. 

 Such parallels are not rare in Nature, and may 

 occur whenever like structures are acted upon 

 in like manner. Yet another spine-clad lizard 

 is found in South and Tropical Africa and in 

 Madagascar. Known as girclled-tailed lizards, 

 and attaining a length of fifteen inches, it differs 

 from the spiny forms just described in many 

 respects. In the first place, the horny spines 

 are backed by bony nodules so that the creature 

 is invested in a complete armour. In the second, 

 the spines are more symmetrical in form and 

 arrangement, constituting, in the back, a broad 

 shield composed of a number of transverse bands. 

 The spines on the base of the head, the neck, 

 and around the tail are very large. The spines 

 of the moloch lizard and of the horned " toads " 

 appear to serve as a disguise rather than as 

 offensive-defensive armour. Concerning the use 

 of the spines of the girdled-tailed lizards we have 

 no definite information. But we have yet another 

 group of armoured lizards to which reference must 

 be made the Thorny-Tailed Lizards ( Uromastix) 

 and in these the armour is defensive. Desert- 

 dwellers, like the forms just described, these 

 creatures diifer conspicuously therefrom, in that 

 the head and trunk are quite smooth, being 

 clothed only in small scales. The tail, however, 

 is armed with strong spines which appear to have 

 been developed in conjunction with the peculiar 

 liabit of these creatures of living in burrows. 



