ON THE ANATOMICAL CHARACTERS DISTINGUISHING 
THE SWALLOW AND THE SWIFT. 
By A. H. Garrop, M.A., F.R.S. 
Ir is not a difficult task, whatever the department of the subject 
which may be under consideration, to classify thinking naturalists 
in one or other of two divisions, dependent upon the nature of the 
facts which they, from opportunity or inclination, are in the habit 
of specially emphasising. There are those who devote them- 
selves to the study of the animal as a whole, its external con- 
formation, its habits, and its haunts. They collect specimens of 
allied species and preserve them according to an arrangement 
which is liable to be modified by the experience of collectors 
generally, and from rumours which reach them as to the results 
arrived at by those of the class to be referred to immediately. 
These latter lay but little stress upon superficial resemblance and 
specific differences, devoting their attention to those facts brought 
to light by osteological comparison or the differences of deep- 
seated soft parts, which throw light upon the mutual relations of 
the larger groups into which the subjects of their study are 
generally acknowledged to fall. 
Now and again the opinions of these two classes of naturalists 
are apt to be diametrically opposed. The one, as the result of 
his experience that intimately allied forms closely resemble one 
another, is apt hastily to draw the illogical conclusion that the 
converse of the proposition is equally true, and that therefore 
animals which closely resemble one another in contour and habit 
must be very nearly related. The other, basing his conclusions on 
different data, does not run the risk of being misled by the decep- 
tive argument, and forms an opinion which has therefore the 
average value of his productions. 
As an excellent example of the above-mentioned opposed 
notions of naturalists, the relation of the Swallow to the Swift 
stands prominently forward. By systematic ornithologists and 
collectors of birds until recently it has always been the habit to 
place these birds in juxtaposition, contrary to the opinion of 
anatomists, just in the same way that the Sand Grouse is grouped 
by them with the Tetraonide, the Petrels with the Gulls, and the 
Secretary Bird with the Caracaras. 
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