Of Dorkings I have examined three skulls, one belonging to the white-sub- breed; the one character deserving notice is the breadth of the frontal bones, which are moderately furrowed in the middle; thus in a skull which was less than once and a half the length of that of G. bankiva, the breadth between the orbits was exactly double. Of Hamburghs I have examined four skulls (male and female) of the pencilled sub-breed, and one (male) of the spangled sub-breed; the nasal bones stand remarkably wide apart, but in a variable degree; consequently narrow membrane-covered spaces are left between the tips of the two ascending branches of the pre-maxillary bones, which are rather short, and between these branches and the nasal bones. The surface of the frontal bone, on which the branches of the premaxillary rest, is very little depressed. These peculiarities no doubt stand in close relation with the broad, flattened rose-comb characteristic of the Hamburgh breed. I have examined fourteen skulls of POLISH AND OTHER CRESTED BREEDS. Their differences are extraordinary. First for nine skulls of different sub- breeds of English Polish fowls. The hemispherical protuberance of the frontal bones (7/68. See Mr. Tegetmeier's account with woodcuts of the skull of Polish fowls in 'Proc. Zoolog. Soc.' November 25, 1856. For other references see Isid. Geoffroy Saint-Hilaire 'Hist. Gen. des Anomalies' tome 1 page 287. M. C. Dareste suspects ('Recherches sur les Conditions de la Vie' etc. Lille 1863 page 36) that the protuberance is not formed by the frontal bones, but by the ossification of the dura mater.) may be seen in figure 34, in which (B) the skull of a white-crested Polish fowl is shown obliquely from above, with the skull (A) of (G. bankiva in the same position. In figure 35 longitudinal sections are given of the skull of a Polish fowl, and, for comparison, of a Cochin of the same size. The protuberance in all Polish fowls occupies the same position but differs much in size. In one of my nine specimens it was extremely slight. The degree to which the protuberance is ossified varies greatly, larger or smaller portions of bone being replaced by membrane. In one specimen there was only a single open pore; generally, there are many variously shaped open spaces, the bone forming an irregular reticulation. A medial, longitudinal, arched ribbon of bone is generally retained, but in one specimen there was no bone whatever over the whole protuberance, and the skull, when cleaned and viewed from above, presented the appearance of an open basin. The change in the whole internal form of the skull is surprisingly great. The brain is modified in a corresponding manner, as is shown in the two longitudinal sections, which deserve attentive consideration. The upper and anterior cavity of the three into which the skull may be divided, is the one which is so greatly modified; it is evidently much larger than in the Cochin skull of the same size, and