264 NATURAL HISTORY. 



merits of this eye-protector, and its secretion escapes through a duct opening upon its inner surface. 

 " Crocodiles' tears " are household worlds, and the reptiles have a large lachrymal gland to each eye. 

 The ear has an outside lid or valve, which can be shut down when the Crocodile dives, and it protects 

 the tympanic membrane, which is otherwise exposed. 



The heart has two auricles, and the ventricle is more or less divided "into two by a septum, or 

 by a cellular arrangement which produces a certain amount of separation of the purified and impure 

 blood.* 



The Nile Crocodile has a wide distribution in Africa, from Egypt to Senegal, and south to near 

 the Cape, and in Central Africa. Specimens are in the British Museum fifteen feet in length, and it 

 will be noticed that the feet are webbed, that the nasal bones form a projection which separates the 

 hinder edges of the nostril, and that the forehead is flat. 



There are two other Crocodiles in Africa, and they are from the west coast. One is very singular- 

 looking, from its long thin snout, f which is truly Crocodilian, from the lower canines being seen to 

 bite in a groove in tlie upper jaw. 



This long, slender-snouted Crocodile grows to a large size, and lives in West and Central Africa, 

 the Gaboon, and the neighbourhood of Lagos. It has plain orbits, and the nasal bones do not reach 

 the nostril. 



The Black African Crocodile J is from Western Africa, Senegal, Gaboon, and the Ogove River, 

 and is-Very unlike its fellow just mentioned, having a broad, short face (like an Alligator), with two 

 bony plates on the eyelids, a turn-up nose; and the nostril is divided in half by the nasal bones, which 

 form a small part of it. The line of the teeth of the upper jaw is very wavy, and they are rather blunt- 

 topped. Its habits are probably those of the Common Crocodile. 



The Madagascar Crocodile has the snout longer, slenderer, and with straighter sides than the 

 Nilotic Crocodiles. 



The eggs of the Crocodiles are small, not larger than those of a Goose, and the little ones come 

 forth very like the parents in shape, with large-looking eyes, a great gape, and a fine set of sharp teeth. 

 Herodotus noticed the wonderful difference in size between the egg and its little tenant at birth and 

 that of the full-grown reptile, and it is indeed very remarkable. 



There are two well-known species of the genus in India, one of which is the Salt-water Crocodile, || 

 which lives in the estuaries of the great rivers and makes its way to sea for a while, and the other is 

 the River and Marsh Crocodile, which is found well in the interior, and even up in the outer 

 Himalayan valleys in not very warm water. 



The first is a large reptile, with many of the characters of a Nilotic Crocodile, but it differs in the 

 arrangement of the scales behind the head. It has no nuchal scales, and the dorsal ones are oval and 

 long, instead of being as broad as long. It grows to a length of fifteen feet commonly, and it is said to 

 reach double that size. One skull is thirty -one inches long, and, in common with all of its kind, has a 

 long ridge on the face. 



A considerable part of the food of this Crocodile is fish, which fall an easy prey, especially to 

 the smaller and youthful reptiles. The old ones, requiring much food, attack every large animal which 

 accidentally approaches them, and in overpowering it the whole of their powers are called into play. 

 Seizing the victim between their capacious jaws, and fastening their long-pointed conical teeth into 

 its flesh, they drag it below water and drown it. As they cannot swallow their large prey they 

 mangle it, tearing oft' pieces by sudden strong jerks. This is performed by lateral motions of the 

 head and front part of the body. 



When the animal, in one of its favourite positions, floats with just the upper part of the head and 

 back out of water, it can still breathe, bear, and see ; and when it dives, the nostrils are closed by valves, 

 a transparent membrana nictitans is drawn over the eye, and the ear, a horizontal slit, is shut up by a 

 movable projecting flap of the skin. 



* The vertebrae have their bodies hollow in front, and are proccelous, and swollen behind, so as to admit of much 

 motion. There are so-called uncinate processes to the ribs, and in the neck they form a remarkable lateral protection of a 

 strengthening kind. 



t Crorodilus catapkractus (Cuvier)=J/emfops cataphractus (Gray). 



J Crocfxlilus nif/er (Latr.) C. valpebrosvs (C\iv\er)=Osteo1 minus tetraspes (Cope)=Crocodilu$ frontarosus (Murray). 



|| Crocodilas porosus (Scb.n.)=CVoco(/77(/,g biporcatus (Cuvier). 



