298 REPTILES. 



The transition from serpents to lizards is happily exemplified 

 by a pretty little animal, common enough in this country, called 



The Slow- Worm (Anguis fragilis), the appearance of which is thoroughly 

 snake-like ; its body is very long and slender, and it has not the slightest appearance 

 of limbs. Yet it is very closely allied to the lizards, as its internal structure clearly 

 shows. The bones of the pelvis, or arch to which the hinder limbs are attached, are 

 found to exist in a rudimentary state, although no outward indication of limbs appears. 

 If this little creature is laid hold of or alarmed, it contracts its body so forcibly as to 



FIG. 323. Stcm-WoRM. 



become perfectly stiff, and then it will break in two with the slightest blow or attempt 

 to bend it. We therefore at once perceive the propriety of one of its Latin appellation^, 

 that of fragilis (brittle). The slow- worm is not only perfectly harmless, but extremely 

 useful, its principal food consisting of slugs, the greatest enemies of the agriculturist. 



In the GrlaSS Snake of North America the condition of the limbs is equally 

 rudimentary. Other species display, as it were, links in a curious chain of gradations : 

 some have two minute feet in front and none behind ; others, as the Sheltopusik 

 (Pseudopus], have only sproutings of the hinder pair. Some have both pairs, but small 

 and weak, set very far apart on the lengthened body, and destitute of toes. In others 

 they become gradually more developed, until we find them at length completely formed, 

 as in 



The True Lizards (Lacerta), remarkable for the activity of their move- 

 ments. Of these we have two native species. 



The Common or Viviparous Lizard (Zooloca), so called because instead of 

 depositing her eggs in the sand to be matured by the warmth of the sun, as other 

 lizards, the female of this species retains them until the young are hatched, and thus 

 they are produced alive. 



The Sand Lizards (Lacerta agilis), are remarkable for the activity of their move- 

 ments. Every one must have remarked with what rapidity they nm from one place to 

 another, and how they caw cling to walls and rocks by means of their long and crooked 

 claws. The food of these lizards consists chiefly of insects. They are timid, harmless 



