Characters of Birds' -eugs. 359 



Eotliscliild) and of the Crowned Pigeon, as examples of the 

 differenth'-sized eggs of birds of nearly similar size. The 

 egg of a Cuckoo is shown surrounded by those of the Tree- 

 Pipit, in tlie nest of which it was laid. 



The next label states that the smallest eggs are tliose of 

 some species of Humming-bird. Of existing birds the 

 Ostrich lays the largest eggs, but these were far exceeded in 

 size by those of the extinct yEpyornis of Madagascar (of which 

 a model is exhibited below the case, being too large to be 

 placed within). Specimens of eggs of Humming-bird and 

 Ostrich follow. 



Texture of Surface. — The surface of the shell of the eggs 

 of different birds varies much in texture. It may be (A.) ex- 

 tremely smooth and polished; (B) smooth and glossy; (C) 

 dull and chalky, or even (D) covered with a distinct calca- 

 reous film, sometimes of considerable and irregular thickness; 

 (E) the surface may be distinctly granulated or pitted. 



Examples of A are given in the wonderfully jjolished eggs 

 of the Rufous and Chilian Tinamou ; of B in those of the 

 Kingfisher and Great Black Woodpecker ; of C in the White- 

 headed Ibis, Megapode, and the very rough egg of the White- 

 headed Duck {Erismatura leucocepJiala) . Section D is 

 represented by eggs of the Chatham-Island Shag [Phalacro- 

 corax featherstoni) , the Guira, the Ani, the Sclavonian 

 Grebe, and the Rosy Flamingo. In the three last-named a 

 portion of the outer chalky crust has been removed to show 

 the hard, and sometimes coloured, shell below. For E the 

 egg of an Emu is selected. 



Colour. — The colour of the egg has no relation to that of the 

 parent bird. WHiite is probably the primitive colour of birds'- 

 eggs, as it is that of the eggs of all reptiles. The eggs of birds 

 laid in holes, either in the earth or trees, entirely concealed 

 from the light, are mostly white. The larger number of eggs 

 are variously coloured by the deposition of pigment on or 

 near the outer surface of the shell. The colour may be uni- 

 form throughout the surface of the shell, or it may be in 

 irregular washes, blotches, more or less circular spots, or 

 lines, upon either a white or uniformly coloured ground. 



