The Mexican Iguana, (_Ctenosaura acanthura_), looks unique in the possession of rings of sharp spines about the tail. Most specimens are jet black when adult, but very young examples are pale green.
The South American Iguana, (_Iguana tuberculata_), may be readily distinguished by the very pronounced fringe of erect spines which rise along the back-bone of male specimens, and also by the presence of a rounded tubercle or plate on each side of the head. This is a brightly colored Iguana, having bars of green, gray and black. It is strictly arboreal, and evinces stronger herbivorous habits than species of the allied genera. A large male specimen is seven feet long, but much of this length is taken up by the gradually tapering tail. In South America--on the Orinoco, at least--this species is considered edible, and the writer can testify that to a hungry man its flesh is excellent.
The very popular Horned "Toad", (_Phrynosoma_), of the southwestern states, of which there are eight or nine species, should be mentioned if for no other reason than to place it where it belongs--with the lizards, and not with the toads.
The Tegus, (genus _Tupinambis_), are powerful lizards, growing to a length of four feet, and inhabiting tropical South America. They are fleet of foot, mainly carnivorous and very quarrelsome. It is impossible to keep any but the larger lizards in the yard with them. Tegus are fond of eggs, breaking the shell at one end and lapping up the contents by means of the very broad, forked tongue. They will also eat raw beef.
The Australian Monitor, (_Varanus gouldii_), is a good representative of a genus of large and powerful lizards confined to the Old World, where they occur in India, Malaysia, Africa and Australia. Monitors grow to a length of eight feet. They are swift runners, entirely carnivorous, and usually dwell in thick jungles. They are able to swallow entire an animal as large as a half-grown rabbit. All are fond of eggs, swallowing them without breaking the shell, which is soon dissolved by the powerful gastric juices.
Other Lizards.--Within the main halls of the Reptile House will be found various representatives of the smaller Lizards, a few of which may be mentioned.