590 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1917. 



I am familiar. The roar or bellow of the larger alligators may be 

 heard for a considerable distance and while hunting in the cane- 

 brake region of northeastern Louisiana in early spring I have lain 

 awake in my blankets far into the night listening to this strange, 

 wierd call. Along the Mississippi River below New Orleans where 

 the muskrats have caused such serious losses through damage to the 

 levees, the alligators, recognized as the principal natural enemy of 

 these burrowers, are protected by local laws. 



The alligator pool in the Zoological Park contains about 25 speci- 

 mens of various sizes; but the smaller individuals, some under a 

 foot in Ivingth, have special quarters. The larger alligators are can- 

 nibals and when hungry do not hesitate to swallow the young of 

 their own species. 



THE LIZARDS. 



Most of the American lizards are graceful and innocent creatures 

 and many are beautifully colored. They are as much a delight to 

 students of reptiles as our warblers are to the ornithologists. There 

 are, however, two large species, found in the Southwest and in 

 Mexico, which are dangerous reptiles. They are known as the beaded 

 or tuberculated lizards, are sluggish creatures inhabiting arid situa- 

 tions, and are the only known poisonous lizards. 



The Gila monster {Heloderma suspectu7n) is laiown only from por- 

 tions of Arizona, New Mexico, Sonora, and southern Nevada. It is a 

 comparatively large species, growing to 20 inches or more in lengtli. 

 In color it is brown or blackish, marked with numerous rings and 

 blotches of yellow or orange. The upper parts are heavily beaded or 

 tuberculated; the tail is fat and stumpy, and the reptile presents 

 altogether a dangerous and terrifying appearance. On account of 

 his notorious disposition and because of his poisonous bite, the Gila 

 monster is much dreaded by residents of the region in which he lives; 

 and the several specimens on exhibition attract great attention. The 

 poison glands are situated on the outer side of the lower jaw near 

 the tip. When biting the Gila monster holds on like a bulldog so that 

 the poison may have time to become absorbed in the wound. No 

 specific antidote is known. 



The iguanas, large lizards of tropical America, are represented in 

 the collection by the rock iguana of Mona Island, near Porto Eico. 

 This species {Cyclura stejnegeri) sometimes reaches a length of over 

 3 feet. It is a ground-inhabiting reptile and is chiefly vegetarian in 

 diet. Iguanas are much sought by the natives for food. 



Several species of the commoner lizards of small size, native to the 

 Southeastern States, are shown. The glossy blue-tailed skink 

 {Enmeccs guinqueUueafus) is one of the most handsome of the east- 

 ern forms. It is common in pine woods, especially in the South. The 



