SCALED REPTILES LIZARDS. 405 



sheath formed by a transverse fold at the front of the hinder portion. A 

 further resemblance to snakes is to be found in the circumstance that these 

 lizards cast their skins in a single piece. As regards the limbs, great variety 

 is presented by the seven genera included in the family, some having the 

 feet fully developed, and terminating in five toes, whereas in others all 

 external traces of limbs have disappeared. It is noteworthy that all the 

 limbed forms are American, and that Central America and the West Indian 

 Islands are the head-quarters of the group. Beyond the New World, two 

 species are found in Europe and North Africa, while a third inhabits Burma 

 and the Himalaya. Of the seven genera, GerrhonotAis&ud. Ophisaurus are 

 peculiar in having a lateral fold on the body ; the former, which is exclusively 

 American, having two pairs of five-toed limbs, while the latter has, at most, 

 external representatives of the hinder pair. This genus includes the well- 

 known scheltopusik (0. apus) of South and Eastern Europe, as well as. one 

 Oriental, and other American types. Of those without folds, the genera 

 Diploglossus, Sauresia, and Panoplus are American and four-limbed, differing 

 from one another in the number of the toes, which vary from one or two to 

 five on each foot. Ophiodes is likewise American, but has only external 

 rudiments of the hind-limbs. Lastly we have Anguis, represented solely by 

 the familiar blind- worm of Europe, Western Asia, and North Africa, which 

 lacks all vestiges of limbs externally, and has the lateral teeth large and fang- 

 like. This species is also peculiar in giving birth to living young, all the 

 other members of the family laying eggs in. the ordinary manner. All the 



Anguidce, live on animal food, the 

 larger kinds killing and eating small 

 mammals, birds, and reptiles, whereas 

 the smaller species confine themselves 

 to worms, insects, slugs, and such 

 like. As a rule they are strictly ter- 

 restrial, although some species of 

 Gerrhotwtus will climb up low bushes. 

 The family AnniellidtE, as con- 

 taining only a single Calif ornian genus 

 with two species, may 

 be passed over with- Poisonous 

 out notice, and we Lizards. Family 

 accordingly proceed Helodermatidce. 

 to the family Helo- 

 dermatidce, which also comprises only 



two species, and ranges from Central 

 Ftg. 17-PoisoNous LIZARD (Heloderma). Amer f ca to New Mex b ico and Arizona , 



In common with many of the poison- 

 ous snakes, these lizards are distinguished by their brilliant coloration, one 

 kind having an orange or yellow ground-colour, with an irregular net-work of 

 dark markings on. the head and body, and dark rings round the tail. These 

 lizards possess a tongue and teeth of the same general type as in the blind- 

 worm, but have the upper surface covered with transverse rows of small 

 granular tubercles, the under-parts being invested with squared scales. 

 From those of the blind- worm the teeth differ by having grooves on the front 

 and back surfaces for the transmission of the poisonous fluid, and there are 

 certain structural differences in the skull. Both species are included in the 

 genus Heloderma, and the one from Arizona is rather the larger of the two, its 



