CROCODILID^. 59 



shields are horny plates ; but, on the back (and, in several American Alligators, on the belly), 

 these plates are merely coverings of hard bony scutes imbedded in the skin, and of the same 

 form and number as the plates. This armour not only most effectually protects the body — a 

 rifle-ball glancing off from it as from a rock — but it also serves as ballast, by the aid 

 of which a Crocodile sleeping on the surface of the water is enabled to sink to the bottom 

 instantaneously on being disturbed, driving out the air from its capacious lungs by which it 

 had been kept floating. 



A considerable proportion of the food of the Crocodile is fish, the proverbial swiftness of 

 which is of little avail when pursued by these reptiles ; they fall an easy prey especially to the 

 young animals, these being more active than the old ones. The latter, requiring a greater 

 quantity of food, attack every large animal which accidentally approaches them, and, in over- 

 powering it, the whole of their powerful organization is called into requisition. Seizing the 

 victim between their capacious jaws, and fastening their long, pointed, conical teeth into its 

 flesh, they draw it, in one moment, by their weight and with a stroke of the tail, below the 

 water and drown it. Their gullet, however, is much too narrow to allow of the passage of 

 the entire body of the victim ; and their teeth being adapted for seizing and holding fast 

 only, and not for biting, they are obliged to mangle the carcase, tearing oflF single pieces by 

 sudden strong jerks. This is performed chiefly by lateral motions of the head and front part 

 of the body ; and we find the bones of the head of the Crocodile much more firmly united 

 with one another, and the processes of the cervical vertebrae much more developed, than in 

 any other Saurian. 



The nostrils are narrow, situated close together at the upper side of the extremity of the 

 snout; the eyes and the ears likewise are near to the upper profile of the head, so that 

 breathing, seeing, and hearing are uninterrupted although the whole animal is immersed 

 in the water, only the upper part of the head being raised above the surface. When the 

 animal dives, the nostrils are closed by valves, a transparent membrane {memhrana nictitans) 

 is drawn over the eye, and the ear (a horizontal slit) is shut up by a moveable projecting 

 flap of the skin . 



When we add that the pupil of some species is horizontal and of others vertical (indicating 

 their nocturnal or seminocturnal habits), that the tongue is short, flat, immoveable, attached 

 to the bottom of the mouth, and that the vent is a longitudinal slit, and not a transverse 

 opening as in other Saurians, we shall have enumerated all the important external pecu- 

 liarities of the Crocodiles. 



The Indian Crocodiles inhabit not only rivers and estuaries, but, according to Cantor, also 

 the sea-coasts, and in calm weather may be seen floating at a distance of two or three 

 miles from shore. Those inhabiting small inland waters which are dried up during a 

 drought are compelled to wander about in search of water, in which alone they can procure 

 their food ; they do this during the night. Some of them, however, especially large indi- 

 viduals, bury themselves in the mud, as many fi-eshwater tortoises and fish do, and remain 

 in a state of torpor below the hard crust during the time of the drought. It is during that 

 period, shortly after they have been released from the state of an enforced fasting, that they 

 are most formidable. Whilst at other periods they quietly wait tiU some victim is brought 

 by accident within easy reach, hunger now renders them more audacious and compels them 

 to go in search of food ; a noise which at other times would scare them away, now attracts 



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