JAMES NE WTON BASKE TT. i o i 



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. In some of the Ptar- 

 migans {Lagopus) 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 ; and a 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 



