BY J. DOUGLAS OGILBT. 211 



mentation of the decaying mass. The aborigines eagerly seek 

 for and plunder the nests of the eggs, which are considered a 

 delicacy. 



In an earlier part of this article mention is shortly made 

 of the different methods of oviposition resorted to by the differ- 

 ent species of crocodilians, and it is there stated that the 

 majority of species simply deposit their eggs in shallow troughs 

 scraped in the sand or mud ; as an example of hatching out 

 the eggs, in contradistinction to the elaborate nests formed by 

 our estuary crocodile, the following account will be read with 

 interest ; it is abstracted from a paper entitled, " On the Ovi- 

 position and Embryonic Development of the Crocodile" (Ann. 

 and Ma;/. Nat. Hist. (6) ix. 1892, p. 66), and is from the pen of 

 Dr. A. Voeltzkow, who, writing on the breeding habits of 

 Crocodilus niloticus, as observed by him in Madagascar, remarks : 



"The nest consists of a pit, excavated in the earth to a depth 

 of from a foot and a half to two feet, with partially steep walls_ 

 At the bottom of the pit the walls are undermined, and here the 

 eggs are placed. The floor of the pit is raised slightly in the 

 middle, so that the eggs, as they are laid by the female, roll by 

 themselves into the hollowed-out places Very rarely one or two 

 eggs are found in the middle of the pit, which may well be 

 taken as proving that the mother does not herself push the eggs 

 into the hollows with her feet, for in that case no eggs would 

 ever be found in the centre of the pit. After the eggs are laid 

 the pit is filled in, and no sign of it can be detected from above. 

 The old Crocodile sleeps upon the nest, and this enables the 

 natives to find the eggs, since they follow the tracks of the 

 animal from the water. Further on Dr. Voeltzkow continues : — 

 " When the young are ready to emerge, the female scrapes the 

 sand out of the pit." He then proceeds to relate how the 

 mother knows that the eggs are sufficiently developed and that 

 it is time to scrape out the pit, This from personal observation 

 he proves to be due to the noise produced by the young animal 

 while still imprisoned within the as yet unbroken shell ; these 

 sounds can be heard at a considerable distance, and the mother 

 while lying on the nest hears them and acts accordingly. "They 

 are," he continues " produced with the mouth closed, apparently 

 by powerful contraction of the ventral muscles, much as we make a 

 noise when hiccoughing. The sound too is similar." According 

 .to the same authorities, the young are unable to extricate them- 



