Having disposed of the two preceding more or less aberrant groups, we come to the principal suborder, that of the Accipitres. Although this suborder is plainly marked from the outside, there are perhaps few groups that have presented more difficulties in the way of a satisfactory arrangement of its various members. Originally these birds were mainly classified on external characters, and it was not until 1867, when Huxley published his Classification of Birds, that the subject was placed on a satisfactory basis of anatomical characters. Since that time additional facts have been accumulated which have enabled systematists to work out a more logical disposition of the Accipitres. One of the first of these was presented by Mr. Ridgway in 1875, and that his views as then expressed were sound is shown by the fact that practically identical results were reached by Mr. Pycraft in 1902. This problem has also been attacked by Dr. Suschkin, a distinguished Russian authority, and he too has arrived at similar conclusions, so that the present arrangement may be taken as the best expression now obtain-able, although it differs quite widely from that accepted by many other students.
As already indicated, this suborder is logically divisible into two families, the Falconidae and the Buteonidce. As the characters on which this division is made are drawn from the skeleton, they are necessarily of a technical nature. The first family (Falconidae) may be defined as follows : The vomer terminates anteriorly in a more or less conspicuous olive-shaped swelling, which is closely applied to the maxillopalatine processes; the palate is directly desmognathous, that is, of the “band type,” while the nasal bones are almost completely ossified, the nostril being a small, usually circular opening; the scapular process of the coracoid is produced forward so as to meet the clavicle.
In the second family (Buteonidce) the vomer is never expanded anteriorly and is more applied to the under surface of the maxillopalatine processes; the palate is indirectly desmognathous or schizognathous (of the “split type”), the nasal bones very incompletely ossified, and the nostrils large and without the bony tubercle; the scapular process of the coracoid is not produced forward, but is separated from the clavicle by a wide interval.