INTRODUCTION. 
Xl 
As I have elsewhere remarked, much useful and highly in¬ 
teresting information might be gained towards the classification 
of birds, by paying some attention to their eggs; and it is very 
gratifying to find, in thus regarding them, that, with the ex¬ 
ception of a few instances, were we to take the eggs of our 
British birds as our only guide, we should arrive at the best 
and most approved arrangement of the different genera. All 
those new genera which have been lately adopted, are clearly 
indicated in the difference of their eggs, and in none more 
than in those of the Snow Bunting and the Bearded Titmouse ; 
the former of which was associated with the genus Emberiza, 
the latter with that of Parus; the very great similarity which 
the eggs of each of these genera (Emberiza and Parus) bear 
to each other, at once pointing out the intruders. I would 
not, however, have any one place too implicit reliance on the 
character of their eggs for the arrangement of the birds. 
There are puzzling instances in which, by so doing, we should 
be led into error, and be tempted to place apart from each other 
the eggs of the Pied and Spotted Flycatchers, the Common and 
Tythis Bedstarts, and to separate those of the Common and 
Misletoe Thrush from the rest of the genus, the Swallow from 
the Martin and the Swift, the Little Bittern from the more 
common species, and the Woodcock from the Snipe; and placing 
too much reliance upon those minute differences which serve so 
beautifully to connect and represent neighbouring genera, we 
should be led into a similar mistake with regard to the eggs 
of the Pied Wagtail, the Grasshopper Warbler, the Wood 
Wren, and the Wheat ear. 
The generic characters of eggs are in some cases as dis¬ 
tinctly marked in contour and in colour as are the birds them¬ 
selves. Any one would immediately recognize the close affinity 
which those of the different species of Crows bear to each other, 
as also those of the Owls, the Ducks, the Divers, the Buntings, 
the Titmice, the Sea Gulls, and the Terns, greatly as the latter 
differ individually. In shape, the eggs of the Grebes are very 
peculiar, as are those of the more typical waders. This affinity 
