16 THE ALLIGATOR'S LIFE HISTORY 



ing when coming out of the water onto the soft earth of 

 the swamps and marshes in which they live. Their head 

 is large, long and flat, with enormous jaws armed with 

 long rows of formidable teeth, both top and bottom. 

 Their necks are short and rigid. Their bodies are heavy, 

 and about one-third the total length is between the front 

 and back legs. The tail is long and heavy, tapering 

 gradually from the hind legs to the end, being much 

 thicker from top to bottom than from side to side, and is 

 keeled on the upper side the last third of its length, 

 which enables them to use it to great advantage when swim- 

 ming. They propel themselves rapidly through the water 

 by powerful sweeps of the tail from side to side. The 

 legs and feet while swimming are folded back against the 

 body and tail. An alligator's body, except the back of the 

 neck and back, is covered with smooth horny scales in 

 transverse rows, for the most part rectangular in shape, 

 separated from each other and connected to each other by 

 narrow bands of heavy, wrinkled, flexible skin. The back 

 of the neck is covered with rather regular rows of heavy 

 bone plates almost square, with rounded corners, and 

 heavily keeled; these are set in the under skin, and provide 

 a strong protective top armor. 



The eye of the alligator is large. Its lens is a vertical 

 slit, which is capable of being expanded or contracted as 

 the light is bright or dull. In bright sunlight the slit is so 

 narrow as to be hardly seen. As the light diminishes, the 

 slit expands until after sundown, the pupil is almost round. 

 The eye is protected by a top and bottom lid, both of which 

 are movable, and which are closed when the alligator is 

 asleep, either on land or under the water. The eye is 

 further protected by a transparent membrane which slides 

 across its lens from front to rear, and is closed as soon as 

 the head of the alligator goes under water. The mem- 

 brane remains covering the eye all the while the head is 

 submerged. Alligators' eyes, as seen by a carbide or elec- 



