MEGAPODITJS. 451 



shaped portions of pure sand along the base (the remnants of 

 successive outer coverings of sand, the basal portions of which have 

 never been removed), ten or perhaps eleven successive renovations 

 of the mound ; even the central portion was perfectly cool. The 

 vegetable matter had in a great measure disappeared, leaving only 

 the hard woody portions behind, but showing where it had been by 

 the discoloration of the sand. The decay of the vegetable matter 

 and the bird's habit (as I judge from appearances) of not removing 

 the basal portion of the sandy covering at each renovation, suffi- 

 ciently explain why the mounds increase so much more in radius 

 than in height. 



A smaller mound, one as I take it still in use, though I could 

 find no eggs in it, contained a much greater amount of vegetable 

 matter, and was sensibly warm inside. I could make no section of 

 it, as it was too full of imperfectly decayed vegetation. I believe 

 that the bird depends for the hatching of its eggs solely on the 

 warmth generated by chemical action. The succulent decaying 

 vegetation, constant moisture, and finely triturated lime, all com- 

 bined in a huge heap, wiU account for a considerable degree of 

 artificial heat. 



I am by no means satisfied that only one pair of birds use the 

 same mound ; on the contrary, the Nicobarese I had with me that 

 day explained, as I understood, that though one pair begin the 

 mound, they and all their progeny keep on using and adding to it 

 for years, and as " Cvssem," or whatever the wretch's sobriquet was, 

 interpreted, the men with us had, during the previous month, taken 

 at one time some twenty eggs out of one and the same mound, which 

 also they took us to see, and which was perhaps &\e feet high and 

 sixteen or eighteen feet in diameter, and which was the freshest- 

 looking I had seen. 



The eggs are excessively elongated ovals, enormously large for 

 the size of the bird. They vary a great deal in size and a good deal 

 in shape ; all are much elongated, but some are more like Turtle's 

 eggs than those of a bird. When first laid, they are of a uniform 

 ruddy pink, as we know from having obtained one before the bird 

 had time even to bury it ; after being buried, so long as the egg 

 remains quite fresh, it continues a pale pink, but as the chicken 

 develops within, the egg becomes a buffy stone-colour, and when 

 near about hatching it is a very pale yellowish brown. The whole 

 colouring-matter is contained in an excessively thin chalky flake, 

 which is easily scraped off, leaving a pure white chalky shell below ; 

 this outer coloured coat seems to have a great tendency to flake off in 

 spots, specks, and even large blotches as the chicken is developed 

 within. Quite fresh-laid eggs rarely exhibit any white marks of 

 any kind, while those more or less approaching hatching (one 

 cannot say incubated in this case) are invai-iably more or less 

 mottled with white. Occasionally fairly fresh eggs are dug out, 

 bearing along their entire length on one side two parallel white 

 hues made apparently by the claws of the mother bird when scraping 



