460 



CROCODILIA 



CHAP. 



with just the nostrils exposed, or in search of food, frogs being 

 their favourite prey, while their main sustenance consisted of 

 " lights," with an occasional mouse, or a piece of solid meat by 

 way of an entrde. Small pieces were bolted. The tough " lights," 

 namely lungs with the windpipe and blood-vessels, were causes of 

 great quarrels. Two or three would get hold of a lump of this 

 kind, tearing at it, and twisting and rolling over in opposite 

 directions. The supply of warm water came through a stout 

 pipe of red india-rubber, and this was an irresistible attraction 

 to the crocodiles. On many a morning the tube was found 

 twisted into a knot, one of the creatures having spent hours 

 in chewing it and in trying to wrench it off. In order to aid 

 digestion they swallowed peljbles. The most favourable 

 temperature of the water was 85° F.; if below 75° F. they 

 refused to eat, but a continued exposure to 60° F. did not hurt 

 them. AVhen the temperature rose above 95° F. they left the 



water, although means had to be taken to 

 prevent them from lying on the hot-water 

 pipes. 



C. niloticus s. vulgaris. — The pre- 

 maxillo-maxillary suture on the palate is 

 W -shaped. The nasal bones form only a 

 small part of the posterior border of the 

 nasal groove. There are eighteen or nine- 

 teen upper and fifteen lower teeth on each 

 side. In old specimens some of the 

 anterior mandibular teeth perforate the 

 premaxillae, as indicated in Fig. 109, and 

 they even pierce through the integument 

 so as to be visible from above. The 

 nuchals are composed of Ibui' large scutes, 

 with a smaller one on each side and 

 sometimes one behind, and there is a row 

 of smaller ])ieces across the occiput. The 

 dorsal shield contains six to eight principal 

 The fingers are webbed at tlie base ; the 

 outer toes are very broadly webbed ; and there is a serrated 

 fringe on the outer side of the leg. The general colour of the 

 adult is dark ulive-brown ; th(? young are paler, witli black 

 spots and vermiculations. The \nider parts are yellowish wdiite. 



Vu:. 109. — Dorsal view of the 

 skull of a very old specimen 

 of Orocodilus niloticus, in 

 which most of the bony 

 sutures are obliterated, 

 X about ^. 



longitudinal rows. 



