142 CROCODILES AND ALLIGATORS. 



crocodile of the Nile. It appears that in Madagascar 

 the egg-laying lasts from the end of August to the end of 

 September, the number of eggs in a nest varying from 

 twenty to thirty. The nest is dug about two feet deep in 

 the dry white sand ; the bases of its wall are gouged out, 

 and into the lateral excavations thus formed the eggs roll 

 from the slightly raised centre of the floor of the nest. 

 Externally the nest is not discernible, but the parent 

 sleeps upon it. The eggs differ greatly in form ; the shell 

 is white, thick, firm, and either rough or smooth, the 

 double shell-membrane being so strong that the egg keeps 

 its form after the shell has been removed. When newly 

 laid, the eggs are very sensitive, and are readily killed by 

 damp or by heat, but the older eggs are hardy. When 

 the young embryos are about to be hatched, they utter 

 distinct notes, which the mother hears, even through two 

 feet of sand, and proceeds to dig open the nest. Before 

 hatching the embryo turns, and in so doing partially tears 

 the fo3tal membranes. With the tip of its snout turned 

 to one end of the egg, the young animal bores through 

 the shell with a double-pointed tooth comparable to that 

 which young birds possess. This tooth appears very 

 early by the time the embryo is six weeks or two months 

 old and may still be seen a fortnight after hatching. 

 Through the small perforation made by this tooth the 

 fluid flows out, softening the adjacent parts, so that the 

 aperture is widened into a cleft. The process of creeping 

 out may take about two hours. The young animal seems 

 large in comparison with the egg ; one measuring 28 cm. 

 in length came out of an egg 8 cm. long and 5 cm. broad. 

 The young crocodiles are wild little animals, and are led 

 to the water by the mother. They utter sounds, especially 

 when hungry, but the pitch of their call is not so high as 

 it was when they were within the egg. 



