EGGS 185 



and some of these tints have their beauty enhanced by the glossy 

 surface on Avhich they are displayed, by their harmonious blending, 

 or by the pleasing contrast of the pigments which form markings 

 as often of the most irregular as of regular shape. But it would 

 seem as though such markings, which a very small amount of 

 observation will shew to have been deposited on the shell a short 

 time before its exclusion, are primarily and normally circular, for 

 hardly any egg that bears markings at all does not exhibit some 

 spots of that form, but that in the progress of the egg, through that 

 part of the oviduct in Avhich the colouring matter is laid on, many 

 of them become smeared, blotched, or protracted in some particular 

 direction. The circular spots thus betoken the deposition of the 

 pigment while the egg is at rest, the blm^ed markings shew its 

 deposition while the egg is in motion, and this motion would seem 

 often to be at once onward and rotatory, as indicated by the spiral 

 markings not uncommonly observable in the eggs of some Birds-of- 

 Prey and others — the larger end of the egg (when the ends differ 

 in form) making way for the smaller.^ At the. same time the eggs 

 of a great number of birds bear, beside these last and superimposed 

 markings, more deeply-seated stains, generally of a paler and often 

 of an altogether different hue, and these are e\ddently due to some 

 earlier dyeing process. The peculiar tint of the ground-colour, 

 though commonly superficial, when not actually congenital with the 

 formation of the shell, would appear to be suff'used soon after. 

 The depth of colouring whether original or supervening is obviously 

 dependent in a great measure on the constitution or bodily con- 

 dition of the parent. If a l)ird, bearing in its oviduct a fully-formed 

 egg, be captured, that egg will speedily be laid under any circum- 

 stances of inconvenience to which its producer shall be subjected, 

 but such an egg is usually deficient in coloration ^ — fright and 

 captivity having arrested the natural secretions. In like manner 

 over excitement or debility of the organs, the consequence of ill 

 health, give rise to much and often very curious abnormality. It 

 is commonly believed that the older a bird is the more intensely 

 coloured will be its eggs, and to some extent this belief appears to 

 be true. Certain Falconidx, which ordinarily lay very brilliantly- 

 tinted eggs, and are therefore good tests, seem when young not to 

 secrete so much colouring-matter as they do when older, and season 

 after season the dyes become deeper, but there is reason to think 



^ That the larger end is protruded first was found on actual experiment by 

 Mr. Bartlett, Superintendent of the Gardens of the Zoological Society, to be the 

 case commonly, but as an accident the position may be sometimes reversed, and 

 this will most likely account for the occasional deposition of markings on the 

 smaller instead of the larger end as not unfrequentlj' shewn in eggs of the 

 .Sparrow-HAWK, Accipiter nisus. The head of the chick is always formed at the 

 larger end (see Embryology). 



