ZOOLOGICAL SOCIETY BULLETIN 



303 



make a number of important observations. \\"e 

 find tiiat tbc curious baliit of running e)n the 

 hind legs, previously described as existing with 

 but one or two Old World lizards, is actually 

 a common habit among the members of the 

 New World I_i^iiaiiidac and the Old World 

 .■igainichw as well. It is a habit almost in- 

 variably confined to strictly terrestrial lizards, 

 with elongated, powerful hind legs, like the 

 Mexican Basiliscs, (Basiliscus), the Ground 

 Iguanas, {Ctciwsaiira), or the familiar Col- 

 lared Lizard, (Crotapliyhn), of the western 

 Uriited States. This kangaroo-like i)osition is 

 always assumed by such species when running 

 very fast. The reason for this habit remaining 

 in obscurity so long may doubtless be ex- 

 plained by the lack of proper facilities of many 

 students for the study of their living speci- 

 mens. Kept in the proverbial small cage, or 

 tcrrarium, these lizards give not a hint of their 

 singular gait. It seems reasonable to suppose 

 that this is an ancestral trait passed down from 

 the gigantic lacertilians of the past, many of 

 which stalked about on enormously developed 

 hind legs while browsing from overhead 

 branches. 



Kept in suitable quarters, where they may 

 exercise and develop a normal appetite, our 

 various species of iguanas have displayed feed- 

 ing habits quite different in contrast to the pre- 

 vailing idea that they are wholly herbivorous. 

 We find, in fact, that the larger, terrestrial 

 species, such as the Rhinoceros Iguana, (Cy- 

 chira cornuta), and the I'>ahania Iguana. ( C". 

 bacloplia). are largely carnivorous, rushing 

 upon small mammals with the same ferocity as 

 the strictly carnivorous Monitors, (J^arainis). 

 Besides, these iguanas will eat birds, eggs and 

 the larger grubs of insects. Even the persis- 

 tently arboreal iguanas are flesh-eaters to a 

 considerable extent. 



In our collection of lizards, the student may 

 note the enormous variability of form among 

 lacertilians. In this order, as among many 

 others of both cold and warm-blooded crea- 

 tures, one phase of evolution has been the 

 marked degeneration of species that have 

 gradually adopted secretive or burrowing 

 habits. We find among our lizards species that 

 are entirely- devoid of external limbs, that pro- 

 gress by lateral undulations, like a snake. .An 

 example of this kind is the .\merican ''Glass 

 Snake," a member of the .liij:;iil(hu\ The 

 make-up is exactly like a serpent, but the pres- 

 ence of eye-lids and ear-openings should de- 

 note lacertine relationship even to the novice. 

 Compare this snake-like creature with one of 

 the big monitors — a giant among lizards — 



and note the great difference in structure and 

 bulk. ICigiit feet long, with powerful limbs 

 and claws as long as those of a leo|)artl, the 

 monitor is fleet, strong and audacious enough 

 to leap upon a fawn and tear at its throat until 

 the victim is overpowered. And between 

 these extremes, we have on exhibition the 

 great series of intermediate forms, some so 

 grotesque as to ap])ear like much overdrawn 

 caricatures of disordered dreams, others so 

 exquisitely beautiful in form and coloration, 

 that correct delineation by an artist might be 

 viewed with derision as quite impossible pro- 

 ducts of Nature. 



One of the most remarkable of our lizards 

 is the Mexican Basilisc, (Basilisciis zittatus), 

 a wonderfully fleet creature with a high, stiflf 

 comb on the rear part of the head, and a 

 greatly elongated tail and hind legs almost as 

 much developed as those of a frog. In some 

 works of Natural History, this species has 

 been described as altogether arboreal. Its 

 habits are actually quite the reverse. Mr. 

 Gustav Sabille, who captured fourteen speci- 

 mens near the East Coast of Mexico, informs 

 the writer that he found these lizards in quite 

 dry, sandy jjlaces. darting about at bewilder- 

 ing speed in company with a large species of 

 .linciva. Mr. Sabille explains that all of the 

 specimens of the Basilisc observed by him ran 

 on their hind legs when pursued. They were 

 so fleet of foot as to appear like a mere streak 

 when running. They appeared as if con- 

 vinced of their ability to easily evade capture, 

 for instead of darting straight away, the 

 course of most specimens was in a semi-circle, 

 and during the heat of mid-day, the collector 

 found it impossible to catch them owing to 

 this dodging. Late in the afternoon they 

 could be cliased into thickets, thence cau- 

 tiously stalked with some success. The antics 

 of these lizards after arrival in the Park w'ere 

 quite in accordance with Mr. Sabille's de- 

 scri[)tion. They are mostly insectivorous, 

 l)ut small flowers are also sometimes eaten. 

 Owing to the needlelike development of the 

 claws, we are compelled to keep them indoors, 

 as several specimens ran up the brickwork on 

 the side of the Reiitile House, hurled them- 

 selves backward, and escaped over the walls 

 of the corral. 



The large yard devoted to the Iguanas has 

 taken on quite a tropical aspect since stocking 

 with a fine series of the large species. .\ 

 bright sunshine brings all of the specimens 

 from indoors. Sprawled about the yard in 

 odd positions, may be seen the big Rhinoceros 

 and the Bahama Iguanas, of dingv brown 



