2508 



SCALED REPTILES 



THE POISONOUS LIZARDS 

 Family HELODERMATID^ 



Two conspicuously-colored lizards, ranging from the isthmus of Tehuantepec 

 in Central America as far north as New Mexico and Arizona, stand alone in the 

 suborder in being poisonous, their bite, in certain cases at least, being sufficiently 

 severe to produce very serious symptoms even on human beings, while smaller ani- 

 mals are soon killed thereby. These two species are the Mexican poisonous lizard 

 (Heloderma horridum) of Western Mexico, and the Arizona poisonous lizard (H. 



ARIZONA POISONOUS LIZARD. 



(One-third natural size.) 



suspectum] from New Mexico and Arizona, the former being known in its native 

 country by the name of silatica. Nearly allied to the blind worm, which they re- 

 semble in the general structure of their tongue and teeth, although distinguished by 

 certain peculiarities in the conformation of the skull, and by the upper surface be- 

 ing covered with small granular tubercles, externally they are characterized by the 

 depressed head, the plump, rounded body, the tolerably long cylindrical tail, the 

 rather short limbs, in which the third and fourth toes are longer than the others, 



