Mr. Layard (7/57. On the Ornithology of Ceylon in 'Annals and Mag. of Nat. History.' 2nd series volume 14 1854 page 63.) has given an account of a breed of fowls in Ceylon with black skin, bones, and wattle, but with ordinary feathers, and which cannot "be more aptly described than by comparing them to a white fowl drawn down a sooty chimney; it is, however," adds Mr. Layard, "a remarkable fact that a male bird of the pure sooty variety is almost as rare as a tortoise-shell tom-cat." Mr. Blyth found the same rule to hold good with this breed near Calcutta. The males and females, on the other hand, of the black-boned European breed, with silky feathers, do not differ from each other; so that in the one breed, black skin and bones and the same kind of plumage are common to both sexes, whilst in the other breed, these characters are confined to the female sex. At the present day all the breeds of Polish fowls have the great bony protuberance on their skulls, which includes part of the brain and supports the crest, equally developed in both sexes. But formerly in Germany the skull of the hen alone was protuberant: Blumenbach (7/58. 'Handbuch der vergleich. Anatomie' 1805 page 85 note. Mr. Tegetmeier, who gives in 'Proc. Zoolog. Soc.' November 25, 1856 a very interesting account of the skulls of Polish fowls, not knowing of Bechstein's account, has disputed the accuracy of Blumenbach's statement. For Bechstein see 'Naturgeschichte Deutschlands' b. 3 1793 s. 399 note. I may add that at the first exhibition of Poultry at the Zoological Gardens in May 1845 I saw some fowls, called Friezland fowls, of which the hens were crested, and the cocks furnished with a comb.), who particularly attended to abnormal peculiarities in domestic animals, states, in 1805, that this was the case; and Bechstein had previously, in 1793 observed the same fact. This latter author has carefully described the effects on the skull of a crest not only in the case of fowls, but of ducks, geese, and canaries. He states that with fowls, when the crest is not much developed, it is supported on a fatty mass; but when much developed, it is always supported on a bony protuberance of variable size. He well describes the peculiarities of this protuberance; he attended also to the effects of the modified shape of the brain on the intellect of these birds, and disputes Pallas' statement that they are stupid. He then expressly remarks that he never observed this protuberance in male fowls. Hence there can be no doubt that this extraordinary character in the skulls of Polish fowls was formerly in Germany confined to the female sex, but has now been transferred to the males, and has thus become common to both sexes. [EXTERNAL DIFFERENCES, NOT CONNECTED WITH THE SEXES, BETWEEN THE BREEDS AND BETWEEN INDIVIDUAL BIRDS.