_Osteological Differences._--I have examined twenty-seven skeletons and fifty-three skulls of various breeds, including three of _G. bankiva_: nearly half of these skulls I owe to the kindness of Mr. Tegetmeier, and three of the skeletons to Mr. Eyton.
The _Skull_ differs greatly in size in different breeds, being nearly twice as long in the largest Cochins, but not nearly twice as broad, as in Bantams. The bones at the base, from the occipital foramen to the anterior end (including the quadrates and pterygoids), are absolutely identical in _shape_ in all the skulls. So is the lower jaw. In the forehead slight differences are often perceptible between the males and females, evidently caused by the presence of the comb. In every case I take the skull of _G. bankiva_ as the standard of comparison. In four Games, in one Malay hen, in an { 261} African cock, in a Frizzled cock from Madras, in two black-boned Silk hens, no differences occur worth notice. In three _Spanish_ cocks, the form of the forehead between the orbits differs considerably; in one it is considerably depressed, whilst in the two others it is rather prominent, with a deep medial furrow; the skull of the hen is smooth. In three skulls of _Sebright Bantams_ the crown is more globular, and slopes more abruptly to the occiput, than in _G. bankiva_. In a Bantam or Jumper from Burmah these same characters are more strongly pronounced, and the supra-occiput is more pointed. In a black Bantam the skull is not so globular, and the occipital foramen is very large, and has nearly the same sub-triangular outline presently to be described in Cochins; and in this skull the two ascending branches of the premaxillary are overlapped in a singular manner by the processes of the nasal bone, but, as I have seen only one specimen, some of these differences may be individual. Of Cochins and Brahmas (the latter a crossed race approaching closely to Cochins) I have examined seven skulls; at the point where the ascending branches of the premaxillary rest on the frontal bone the surface is much depressed, and from this depression a deep medial furrow extends backwards to a variable distance; the edges of this fissure are rather prominent, as is the top of the skull behind and over the orbits. These characters are less developed in the hens. The pterygoids, and the processes of the lower jaw, relatively to the size of the head, are broader than in _G. bankiva_; and this is likewise the case with Dorkings when of large size. The terminal fork of the hyoid bone in Cochins is twice as wide as in _G. bankiva_, whereas the length of the other hyoid bones is only as three to two. But the most remarkable character is the shape of the occipital foramen: in _G. bankiva_ (A) the breadth in a horizontal line exceeds the height in a vertical line, and the outline is nearly circular; whereas in Cochins (B) the outline is sub-triangular, and the vertical line exceeds the horizontal line in length. This same form likewise occurs in the black Bantam above referred to, and an approach to it may be seen in some Dorkings, and in a slight degree in certain other breeds.