JAMES NEWTON BASKETT. 101 
shared by some Heron-forms and by Flamingoes, to which 
groups the Pelican-forms are evidently akin. 
But my purpose in noting this chalky incrustation was not 
to emphasize the affinities. It is supposed to indicate an in- 
completeness in the structure of the shell—from what cause 
we can only guess. But so far as I know it is invariably 
white, and often deposited over a sub-surface that is colored. 
Now while it is incomplete it is the latest deposit, and having 
no color in it, it shows a tendency toward loss in color—a 
reversion, as if the bird now was trying to lay a white egg. 
The Cuckoo’s egg also fades rapidly upon exposure. 
On the contrary some of color modification in eggs must 
be progressive, and of course recent. Insome of the Ptar- 
migans (Zagopus) the pigment has over it no shell structure 
whatever. The deposition is so recent and superficial that 
it may be rubbed off when freshly laid, and the primary tint 
beneath is very like that of some sister Grouse that do not 
lay a highly marked egg. Here, then, is an egg that seems 
to be changing to suit its present environment ; anda glance 
at it will strongly impress any one that its modern coloring 
is in keeping with the dead-leaf nest-lining now used by the 
bird. The eggs of the Canada Grouse (Dendragapus cana- 
densis) show marked similarity to those of the Ptarmigans, 
and the eggs of the others grade on down to very faint dots 
over a creamy or dirty ground, so usually characteristic of 
the Fowl group. 
The shape or direction of some egg-markings seem to in- 
dicate the progress of the egg through the oviduct. A 
change, therefore, in the style of an egg involves a great deal. 
Other eggs, however, seem, judging from the sharpness of the 
outlines, to depend upon the peculiar shape of the deposit- 
ing surface. Both are dependent upon the quantity and 
intensity of the staining secretion. 
However this may be it is well known that, variable as they 
are, there is no better diagnostic feature than the style of 
these markings, If they be the result of motion, that motion 
