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ORDERS OF REPTILES— CROCODILES AND ALLIGATORS 
General Characters of Crocodilians. — A 
crocodilian is a lizard-like reptile, of very large 
size, with short, thick legs, a long tail, and the 
most highly developed vascular system to be 
found among reptiles. Its back and neck are 
protected by powerful armor consisting of rough, 
lozenge-shaped plates of solid bone set in a very 
thick and tough skin, and arranged in rows, both 
lengthwise and crosswise. 
Both the tail and the abdomen and throat are 
covered by a regular arrangement of tough scales. 
The whole animal is covered by a thin, trans- 
parent epidermis which is impervious to water. 
The tail is long, flattened vertically, and fringed 
The eyelids are movable, dnd the ear opening 
closes tightly by a flap of skin controlled by 
voluntary muscles. 
Most saurians are voiceless or nearly so; but 
the alligator emits a very deep bellow, or roar, 
which in animals over ten feet in length is much 
lower on the scale than any fog-horn. 
“The difference between a crocodile and an 
alligator” (a question that has been asked a 
countless number of times) consists chiefly in 
the shape of the head, and the manner in which 
the teeth are placed in the lower jaw. The typi- 
cal crocodile has a narrow, triangular head, ter- 
minating in a rounded point. The head of an 
1. GAVIAL. 2. ORINOCO 3. FLORIDA 4. INDIAN 5. MISSISSIPPI 
CROCODILE. CROCODILE. CROCODILE. ALLIGATOR. 
along the top with a row of lofty, saw-toothed 
scales of great use in swimming. 
The head is a mass of well-nigh solid bone, 
overlaid by the same thin layer of scaly epi- 
dermis which covers the body, of the thinness 
of writing-paper. The nostrils are placed far 
forward, near the end of the snout. The jaws 
possess great strength, and are armed with rows 
of sharp-pointed, conical teeth which are shed 
when worn out, and renewed. 
The tongue is not free, but is firmly attached 
to the bottom of the mouth. Its color never is 
red, but usually is yellowish-white, and some- 
times pinkish. The iris of the eye is dark 
green, and the pupil is very narrow, and vertical. 
alligator is broad, with almost parallel sides, and 
at the end it is broadly rounded off. The canine 
tooth in the lower jaw of a crocodile fits on the 
outside of the upper jaw, in a notch close behind 
the nostrils; whereas in the alligator, the same 
tooth fits into a pit in the upper jaw. just inside 
the line of the upper teeth. 
The heads of living crocodilians show wide 
but progressive variations in breadth, as the an- 
nexed series of figures reveal. The gavial, of 
the Ganges and Jumna, in northern India, has a 
snout like the handle of a saucepan, set with 
four rows of long and very sharp teeth. After 
the gavial of Borneo, its nearest relative is the 
Orinoco crocodile. At intervals come in the 
