EGGS 185 
and some of these tints have their beauty enhanced by the glossy 
surface on which 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 which 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 blurred 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 evidently 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 suffused 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 bird, 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 lke 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 
1 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 unfrequently shewn in eggs of the 
Sparrow-Hawk, <Accipiter nisus. The head of the chick is always formed at the 
larger end (see EMBRYOLOGY). 
