224 ON THE HABITS OF CERTAIN REPTILES. 



the eggs are covered by 1-2 metres of sand, the sounds are duller 

 bvit still distinct at the length of a room. This ciying of the 

 young can be induced by walking heavily past the receptacle 

 containing the eggs, by knocking against it, by taking an egg in 

 the hand and teaming it : in fact, any shock causes the young one 

 to lift up its voice in the egg. 



" As the female visits the nest almost daily in order to convince 

 herself of its orderly condition, her passage from the water to 

 the nest and back shakes the ground and induces the production 

 of sound by those young ones which are sufficiently developed. 

 Thereupon the old one scrapes the sand out of the pit and 

 presently the young emerge. When eggs from my boxes were 

 dug up and kept exposed immediately after the first sounds were 

 heard, the young emerged in about three days. 



"The fact that the young give out sounds was unknown to 

 the natives, and no one believed me until convinced by actually 

 listening to (the sound in) the egg. 1 demonstrated this striking 

 discovery to the English Consul and to the French officials at 

 Majunga. 



" The sounds are produced with the mouth closed, apparently 

 with strong contraction of the ventral muscles sometimes, as we 

 produce hiccough sounds, and the tone is similar." 



In this paper there is also a reference to an observation by 

 Humboldt who, in the case of Grocodilus acutus^ notes that when 

 incubation is complete the female returns and calls the young, 

 which answer her voice. 



Dr. Voeltzkow states that there is nothing to show whether 

 this statement was founded on Humboldt's own observations or 

 was simply repeated from native observation. 



There is a little doubt as to the identity of the species observed 

 by me, but Mr. G. A. Boulenger, F.R.S., in a letter to Prof. 

 Poulton, states that he regards the common Lagos crocodile as 

 identical with C. nilotictis. My species is the common crocodile 

 of the Lagos district, the largest I have seen measuring 9 feet 

 from snout to tip of tail, and I have no doubt that it is the 

 western form of oiiloticus ; but as the habits here described do 

 not appear to have been recorded from the West Coast and as 

 some of the facts may be new, I have felt it desirable to put my 

 own account on record. 



