573 



proper, the Alligator (q.v. ), and the (Javial (<|.v.). 

 rin- mo-t distinctive characters are as follows : 



''rmtls. The body, which is provided with a 

 ln>,', laterally oompraMed, crested tail, i- covered 

 with an armature oi scales and dorsal lony 'scutes.' 

 The latter cxliil.it :i -M-ulptured appearance. There 

 are four short, strong limlw, with live lingers and 

 four tm-.. which are webbed in various degrees of 

 completeness. The three inner digits bear claws. 

 (ilands witli a musk-like secretion arc found on tin' 

 margin of the lower jaw, at the side of the cloaca! 

 aperture, and on the posterior margin of the dorsal 

 shields. The musky odour is strongest during the 

 season of love. The nostrils lie close together at the 

 point of the snout, and can be closed by valves; the 

 eves possess third eyelids, and the pupil is a vertical 

 >iit in nocturnal species; the tympanum of the ear 

 N "\erhung by a fold of skin which closes during 

 diving : the cloaca has a longitudinal aperture. 



.s'/Wc/(//i. Between the skull and the hip-girdle 

 there are always twenty-four vertebne, and behind 

 the sacrum a large ana variable number of caudal 

 pieces. The vertebne are proccelous that is to say, 

 hollow in front and bear ribs in the neck as well 

 as in the thoracic region. The ribs are provided 

 with two heads for articulation with the vertebra', 

 and those in the middle of the thorax give off 

 hook-like, backward-turned (uncinate) processes 

 which also occur in Birds (q.v.). A breast-bone, 

 witli which the thoracic vertebra? are connected, 

 is always present,, and behind this a number of 

 posterior rib-like processes ( ' abdominal ribs ' ) form 

 a further support. These arise from ossification of 

 septa between the muscles. In the breast-girdle 

 the clavicle is absent ; the hip-girdle is normal. In 

 the large skull the chief peculiarity is the forma- 

 tion of a closed bony palate. By the internal union 

 of premaxilliB, maxilla), palatines, and pterygoids, 

 the roof of the mouth is complete, and the posterior 

 aperture of the nostrils is thus shunted back to the 

 very beginning of the glottis. The development of 

 the skull has been studied by Parker. The mouth- 

 opening is very large, and the jaws bear numerous, 

 usually conical, hollow teeth, implanted in distinct 

 sockets, with reserve germs, at first on the inner 

 side, and afterwards within the pulp cavities of the 

 old ones. 



The nervous system calls for no special remark. 

 The peculiarities of nose, eye, and ear have been 

 notea above. The animals have large lachrymal 

 glands, and their ' tears ' are proverbial. The tym- 

 pana communicate with the mouth by three Eusta- 

 chian tubes, one median and two lateral. As 

 regards the alimentary system, the flat tongue is 

 lixed to the floor of the mouth, the mouth-cavity is 

 bounded behind by two soft transverse membranes. 

 These meet when the crocodile is drowning a 

 victim, and prevent water rushing down the throat. 

 The stomach is in several respects like that of 

 birds. The circulatory system is of importance, 

 since in crocodiles for the first time the heart is 

 four-chambered (see CIRCULATION). The partition 

 between the ventricles is here complete, but as two 

 aortic arches remain, mixed blood still goes to the 

 posterior body. The left aortic arch carries only 

 venous blood to the viscera, whereas in other 

 reptiles it carries mixed arterial and venous. The 

 pulmonary arch carries purely venous, the right 

 aortic arch purely arterial blood. The right and 

 left aortic arches communicate at their roots just 

 outside the heart by a small aperture the foramen 

 Panizzas. The respiratory system presents no 

 special peculiarity except in the backward shunt- 

 ing of the internal opening of the nostrils. When 

 drowning its prey, and with its half-shut mouth in 

 . consequence open to the water, the crocodile keens 

 the tip of its snout on the surface, the glottis is 

 pushed a little forward to meet the posterior open- 



ing of the nostril*, a complete air channel ut thus 

 made, and respiration can go on unimpeded. The 

 air is drawn into the lungs when the rib* expand, 

 and an incipient diaphragm is also of use. The 

 lungs are inclosed in pleura! sacs. There is no 

 urinary bladder. 



Mode of Life. Crocodiles are predominantly 

 aquatic animals, and move rapidly by means of 

 their powerful tail strokes. They are clumsy 

 when ashore, and suffer from being stiff-necked. 

 The body drags somewhat on the ground. They 

 feed on fishes, especially in their youth, and on 

 quadrupeds, which they catch by the river-side, 

 and kill by drowning. If the prey cannot he 

 readily torn, it is often buried till it begins to rot. 

 For their shore work they prefer the darkness, but 

 they also like to bask in the tun. They very often 

 float in the water with their snout and upper back 

 above the surface. The eggs, which are firm, 

 though not thick-shelled, are laid in layers in 

 holes on the banks. They are about the size 'of 

 goose eggs, and the disproportion letween the 

 newly-hatched young and the adults is very strik- 

 ing. The females of some species are said to guard 

 their young. Crocodiles are on the whole sluggish 

 animals, and are very remarkable in the long con- 

 tinuance of the slow growth, which hardly seems to 

 reach a limit as in other animals. 



The crocodile has acquired in literature a char- 

 acter for deceitfulness which is largely undeserved. 

 The conceit of ' crocodile's tears ' ( the animals have 

 large lachrymal glands) was common in Shake- 

 speare's time. Spenser describes (Faerie Queene, L 

 v. 18) the 



Cruell craftie crocodile, 



Which, in false griefe hyding his harmefull guile, 

 Doth weepe full sore, and sheddeth tender teares. 



Another quotation given by Richardson (see 

 Kitchin's edition of the Faerie Queene, Clarendon 

 Press) is still more libellous, 'as cursed crocodile 

 most cruelly can tole with truthlesse teares unto 

 his death the silly pitieing soule.' Kitchin refers 

 also to the invention of the adjective ' crocodilian ' 

 to express a depth of deceitfulness. 



Different Forms. The order of crocodiles includes 

 twenty-five living species, distributed in three 

 families and a doubtful numl>er of genera. They 

 are all found in tropical and warm regions. The 

 three types may be thus contrasted : 



There are altogether a dozen different forms of 

 Crocodile proper, some of which have been 

 dignified as separate genera. The crocodile of 

 the Nile (C. vulgaris) is a well-known species, 

 not now found farther north than Thebes, but 

 occurring abundantly farther south and east. 

 Several varieties are known. It is said sometimes 

 to attain a length of 30 feet, though half that is 

 considered large. It often fatally attacks man, and 

 feeds very largely on smaller mammals. It grows 

 very slowly and continuously, and, with the excep- 

 tion of man, has few formidable antagonists after 



