248 BRANCH CHORDATA 



only, perhaps not over i inch. " Horned toads " will endure long fasts. 

 They hibernate in winter. All species are viviparous and the young at 

 one litter number seven or eight. 



Another Iguana {tuberculata) , of South and Central America and the 

 West Indies, is sometimes 5 or 6 feet long and weighs nearly 30 pounds. 

 It spends much of its time in trees, but when alarmed plunges into the 

 water below it. It lays about two dozen eggs in a hole in the side of the 

 bank. The flesh of these animals is much prized for food by the natives. 



The Monitors. — The one genus ( Var'anus) of this family ( Varan' ida) 

 consists of about thirty species. They are found in Africa, but not in 

 Madagascar, in Australia, and in Southern Asia. They have long forked 

 extensible tongues. They are large, attaining the length of 4 or 5, or even 

 6 feet. Some are found in desert or dry regions, while others are semi- 

 aquatic. The natives of some regions use the flesh of the monitors for 

 food. The monitors are rapacious, devouring any animals which they 

 can get. "The Monitor {Var'anus nilot'icus) is a great water-lizard that 

 lives in the Nile. It is the principal enemy of the crocodile. When full 

 grown it reaches a length of 6 feet or more." — Kellogg. 



Library Work. — See Gadow or other large works on reptiles 

 for an extended description of Lacertilia of the tropical regions. 

 The " Flying Dragon " and other interesting forms are well 

 worth your study. Baskett and Ditmar's " Story of Amphib- 

 ians and Reptiles " relates many interesting facts in a simple, 

 yet instructive manner, also, Hornaday's " American Natural 

 History." Do not fail to read the larger works. Get beyond 

 mere text-book study of these wonderful forms in this and other 

 lands. Broaden your own horizon. 



ORDER IV. CHELONIA 



Turtles vary in size from a few inches in length to 6 or more 

 feet in some marine forms. The turtles of to-day are small as 

 compared with some extinct forms. They vary in weight from 

 a few ounces to over 1000 pounds. There are marine, fresh- 

 water, and land forms, while the " gophers " of the South bur- 

 row in the ground. 



Skeleton. — Turtles are easily recognized by their shell or 

 exoskeleton. The dorsal portion of the shell is called the cara- 

 pace, and the ventral portion the plastron. The covering of this 

 shell consists of horny epidermal plates. These are thin, and 

 when pulled off reveal the bony shields beneath. 



The bony carapace (Figs. 204, 205) is composed of the spines of 

 the dorsal vertebra?, flattened, the ribs broadened out and joined 

 to each other by sutures, also to the outer marginal row of 



