THE SCALE-FOOTED LIZARDS 



2475 



of the hind-limbs, although the front pair have quite disappeared externally. 

 According to the opinion of Mr. Boulenger, the scale foots come nearest to the 

 geckoes, with which they agree in the essential characteristics of their skull, as they 

 do in the nature of their tongue, the want of movable eyelids, and the vertical pupil 

 of the eye; although the latter characteristic, as being variable in the geckoes, can- 

 not be regarded as of much importance. Apart from their external form, they differ 

 from the geckoes and thereby resemble the members of the next family in that the 

 inner extremities of the collar -bones are not expanded into a loop-shaped form, 

 while they are peculiar in that the number of bones entering into the composition 

 of each half of the lower jaw is reduced from six to four. The small and numer- 

 ous teeth are closely set, and have generally long, cylindrical shafts, and blunted 



COMMON SCALE-FOOTED LIZARD. 



(Two-thirds natural size.) 



summits; although in the genus Lialis they are sharply pointed, swollen at the 

 base, and backwardly curved, thus resembling those of the monitors. The hinder 

 limbs are represented externally by a scaly flap, which is most developed in the 

 genus to which the figured example belongs; the component bones may be felt more 

 or less distinctly, and the skeleton of the common species shows five toe bones. 



The common scale-foot (Pygopus lepidopus), which attains a length of about 

 twenty inches, and has a tail twice as long as the head and body, is the typical rep- 

 resentative of the few members of this family. The head is long, pointed at the 

 snout, and scarcely separated from the body, being covered above with large sym- 

 metrical shields, and on the sides with small scales. The ear has an oblique oval 

 aperture, and the rudimental immovable eyelids are circular and covered with 



