1903 Notes on the Nests and Eggs of Birds 1 29 



for existence which has been going on for countless ages 

 in the history of the world. The eggs of all known reptiles 

 (from which birds are supposed to be an offshoot) are whole 

 coloured as to their shells, white, or dingy yellow — with 

 perhaps one exception, the Tuatera lizard of New Zealand 

 being said to show a distinct tendency to produce a coloured 

 rust-spotted shell. Primarily the eggs of all birds must 

 have been white, from the inherent colour of the salts of 

 lime and magnesia of the shell (' Zool.,' 1889, p. 547). And, 

 going back to the earlier forms of bird-life, fossil eggs of the 

 extinct dinornis and aepyornis have been found to approxim- 

 ate in shape, colour, and texture of shell to those of the 

 ostriches of the present day. Ostriches — belonging to the 

 ratite or keel-less breast-boned birds — are structurally the 

 most reptilian family of avian existence ; they lay elliptic- 

 shaped eggs, of one tint, with hard flinty shells, which are 

 highly polished in South Africa, rough surfaced in North 

 Africa ; they are polygamous, several hens laying in one 

 nest. Cassowaries do likewise, but their eggs are green, 

 and rough shelled. Emus lay from 9 to 13 eggs, and the 

 male only sits. The apteryx lays but a single egg, and 

 deposits it in a hole in the ground. Amongst carinate or 

 keel breast-boned birds there are still some peculiarly rep- 

 tile-like affinities. Thus in the hoatzin, for instance, the 

 chicks have claws at the end of their bastard wing bones, 

 and these claws they use, like quadrupeds, for creeping 

 about. Our coot has a similar claw, though not so fully 

 developed, and also in its infancy makes use of it for a 

 similar purpose. This bird and its allies, moorhens and rails, 

 which have also wing spurs, build nests of rough construc- 

 tion. The Megapodes make in place of nests huge earth- 

 mounds, wherein they place their eggs to incubate, our own 

 grebes approximating to the same habit. (Cf. ' Birds of 

 Norfolk,' vol. hi., where Mr Southwell relates his experience 

 of testing the heat of three great crested grebes' nests, 

 their temperatures ranging from 67 to 73° whilst the 

 maximum shade temperature of the day was only 58 ). 

 Penguins lay two greenish-white eggs on the ground, or in 

 a hole in the ground, with practically no nest : these lowly 

 organised birds swim with their wings and use their feet as 

 vol. 11. — no. 6. 1 



