218 THE ZOOLOGIST. 
Let us look into the subject a little more closely. The common 
Swift and the common Swallow are birds which intimately resemble 
one another in many respects. Their size and general coloration 
are much the same. In both the beak is very broad and short; 
the first bone of the pointed wing, which corresponds to the 
human upper arm bone, being also particularly short; whilst the 
bones of the wing which agree with those of the fore arm—the 
radius and the ulna—are proportionately very long. In both the 
feet are small, and the power of progression on the ground feeble, 
each living almost entirely on the wing, making the smaller insects 
its staple article of food, and each building its nest in walls or 
eaves of roofs, not in the branches of trees. 
This collection of external resemblances would generally be 
accepted as sufficient evidence that the Swallow and the Swift 
are closely allied birds; in other words, that in the pedigree of 
the bird-class they sprang from a common ancestor, at some, 
zoologically speaking, comparatively recent time. Further, the 
fact that the two birds are described next to one another, or 
placed side by side in collections, by many of those who are in 
the habit of employing a systematic method of arranging the 
different genera, would show that such ornithologists consider 
the relationship between the Swallow and the Swift to be more 
intimate than that between either of these birds and the Sparrow, 
Crow, Starling, Lark, &c. But all these last-named birds are 
what are known as Passerine ; in other words, they possess certain 
anatomical peculiarities in their organization, found in them all, 
and in no other group of birds. If, therefore, the Swift and the 
Swallow are more nearly related to one another than either is to 
any other passerine bird, then, as the Swallow is most certainly 
passerine, the Swift must be so also. 
But certain naturalists assert that the Swift is not a passerine 
bird at all, and, if they are correct, it is evident that the Swallow 
and it cannot have anything to do with one another, Upon this 
assumption, therefore, the passerine Swallow is much more closely 
related to the Sparrow, the Crow, and the Lark than it is to the 
Swift. 
The question then presents itself—Is it really the case that the 
importance of the deep-seated anatomical resemblances between 
the Swallow and the Sparrow, and of the differences between the 
Swallow and the Swift, is sufficient to justify us, notwithstanding 
