ANATIDAE. 



CHAULELASMUS STREPERA (L.). 



Greenish: the chalk layer lying immediately under the almost 

 colourless glutinous layer is tinged bluish green; under it lies a 

 layer which is tinged faintly yellowish and which merges into white 

 towards the inner membrane (the fundamental layer is not coloured 

 green). 



Yellowish: the chalk layer lying immediately under the dirty- 

 yellowish tinted glutinous layer is Wng&d extremely faintly sea green ; 

 under it follows a cream coloured layer which, as in the case of 

 greenish eggs, merges into white towards the inner membrane (the 

 fundamental is not coloured green). 



NETTION CRECCA (L.). 



The chalk shell underlying the yellowish tinted glutinous layer 

 is cream coloured to the inner membrane (green is not noticeable 

 in any of the chalk layers). 



QUERQUEDULA QUERQUEDULA (L.). 



Yellowish: the chalk layer lying immediately under the dirty- 

 yellowish tinted glutinous layer, is tinged almost imperceptibly with 

 bluish white; under it, all the layers, down to the inner membrane, 

 are cream coloured. 



Greenish: the uppermost chalk layer is of a distinct bluish green 

 colour; for the rest, as in the case of yellowish eggs. 



AYTHIA FERINA (L.). 



The chalk layer lying immediately under the more or less dirty- 

 yellowish tinted glutinous layer is of a light sea green colour; the 

 next layer has a greyish tint, whilst the fundamental layer is coloured 

 sea green. 



