JAMES NEWTON BASKETT. 103 
Just what this stimulant is we may never know. That it 
is dependent in some measure on food is probable, and that 
climate affects egg-colors is certain; but in what way is the 
question. The coloring matter has been thought to be 
closely connected with the waste products or coloring of the 
blood and bile. In the one case the bird may be putting on 
ashes for beauty merely, and in the other she may be like 
the rest of us—stimulated into her .best work or hampered 
into her worst by the “condition of her liver.” 
Perhaps it is scarcely necessary to say that there is no 
relation between the color of a bird’s plumage and its eggs. 
The Peacock and the Humming-bird in all their gaudiness 
lay plain white eggs. 
A few thoughts now about shape and I am done. Natu- 
rally, if left to itself, the shape of the egg would be globular, 
because before the shell is hardened it is fluid. In the 
reptiles it is said always to be globular or ellipsoidal. The 
last condition is doubtless brought about by compression ; 
and in some serpents, perhaps on account of close quarters, 
the shape is much elongated. 
Birds inherited these shapes from the reptiles. In many 
of them the globular and the ellipsoidal shapes yet prevail 
—especially in the lower forms. But in most birds there 
is a distinct ovoid shape, with one end smaller than the 
other. 
We know not what has brought about the various forms 
in birds’ eggs, but the impression is strong that the ovoid 
shape is in some way connected with incubation and pos- 
sibly with upright or bipedal posture. The best illustration 
with regard to its correlations with incubation is seen in some 
of the narrow-breasted Plover-forms, where the number of eggs 
is usually three, or oftener four, with very sharp points at one 
end; and they are found in the nest with the points toward 
the centre. It is of record that if disarranged the bird 
turns the points all inward before “ going on” again. 
In some Gulls similar eggs are found on one side of this 
