460 



CROCODILIA 



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 entrie. 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 pebbles. 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. When 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 to 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 

 Fig. 109.— Dorsal view of the nuchals are composed of four large scutes, 

 'f"^°''V,''^ "^7 ?•'""'" with a smaller one on each side and 



or CrocoailifjS niloticus^ m 



whi£h most of the bony Sometimes One behind, and there is a row 

 xfw a'' ''""''''"^' of smaller pieces across the occiput. The 

 dorsal shield contains six to eight principal 

 longitudinal rows. The fingers are webbed at the 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 olive -brown ; the young are paler, with black 

 spots and vermiculations. The under parts are yellowish white. 



