XV CLASSIFICATION 387 
I will now, taking a few typical cases, give the 
reasons why some birds which have a superficial 
resemblance should be separated from one another, 
and why others which at first sight are very unlike 
must be counted as near relations. What reason is 
there for putting Fowls and Pigeons in different 
orders, or at any rate in different sub-orders? The 
young Pigeon is born blind and is helpless for about 
nine days ;1 the young Chicken is able to run at once. 
In the Pigeon the tail has only twelve feathers, in 
the Chicken, eighteen. How is a Penguin to be 
distinguished from an Auk, a Puffin, or a Razorbill ? 
‘The Penguin has no apteria, or featherless spaces, a 
unique, or almost unique, characteristic. The Heron, 
the Stork, and the Adjutant are born helpless, then 
pass through a down stage, and are, therefore, to be 
distinguished from the Crane, which is born with 
down upon it, and runs a few hours after birth. The 
Petrel is related to the gigantic Albatross; in each 
the nostrils may be seen as raised tunnels running 
for some distance along the top of the beak, and, 
hence, they are called Tubinares. The Water-ouzel 
is not distantly related to the Thrushes ; like them 
he has the first or outermost primary wing-feather 
very short, and the second shorter than ‘the third or 
fourth. And yet he has the habits and look of a 
water-bird ; he dives and holds on to stones at the 
1 Mr. Seebohm and Mr. Mivart are in error when they state 
that no pigeons pass through a down stage. I have seen the 
down upon a young Stock dove, and also upon the young of 
Columba Bollt. See also Bronn’s Thier-Reich, vol. “Aves,” 
where Dr, Gadow figures the nestling down feather of a Pigeon. 
CC 2 
