In the emeu the wing is less atrophied than in the cassowary, but is not yet completely degenerate. Altogether seventeen remiges are represented, of which seven correspond to primaries. Since, however, these feathers have each an aftershaft as long as the main shaft—like the rest of the body feathers—it may be that they answer not to remiges, but to major coverts.
The wing of apteryx, like that of the cassowary, has become extremely reduced. The remiges are thirteen in number, four of which answer to primaries. These feathers are specially interesting, inasmuch as they retain throughout life a stage corresponding to that seen in the very young cassowary, the calamus being greatly swollen, and supporting a very degenerate rhachis and vane.
The penguins afford another object-lesson in degeneration of this kind. Here the wing has become transformed into a paddle, clothed on both sides with a covering of small, close-set feathers. A pollex is wanting, as in the cassowary, emeu and apteryx, while it is impossible to say whether remiges are represented or not.
Authorities.—The following authors should be consulted for further details on this subject:—
For General Reference as to Structure, Colour, Development and Pterylosis.—H. Gadow, in Newton’s Dictionary of Birds (1896); W.P. Pycraft, “The Interlocking of the Barbs of Feathers,” Natural Science (1893).
On the Colours of Feathers.—J.L. Bonhote, “On Moult and Colour Change in Birds,” Ibis (1900); A.H. Church, “Researches on Turacin, an Animal Pigment containing Copper,” Phil. Trans. clix. (1870), pt. ii.; H. Gadow, “The Coloration of Feathers as affected by Structure,” Proc. Zool. Soc. (1882); Newbegin, Colour in Nature (1898); R.M. Strong, “The Development of Color in the Definitive Feather,” Bull. Mus. Zool. Harvard College, vol. xl.
On Moulting.—J. Dwight, “The Sequences of Plumage and Moults of the Passerine Birds of New York,” Annals N.Y. Acad. Sci., vol. xiii. (1900); W.E. De Winton, “On the Moulting of the King Penguin,” Proc. Zool. Soc. (1898-1899); W.P. Pycraft, “On some Points in the Anatomy of the Emperor and Adélie Penguins,” Report National Antarctic Expedition, vol. ii. (1907).
On Development of Embryonic, Nestling and Adult Feathers.—T.H. Studer, “Die Entwicklung der Federn,” Inaug.-Diss. (Bern, 1873); “Beiträge zur Entwickl. der Feder,” Zeitsch. f. wiss. Zool., Bd. xxx.; J.T. Cunningham, “Observations and Experiments on Japanese Long-tailed Fowls,” Proc. Zool. Soc. (1903); H.R. Davies, “Beitrag zur Entwicklung der Feder,” Morph. Jahrb. xiv. (1888), xv. (1889); W.P. Pycraft, “A Contribution towards our Knowledge of the Morphology of the Owls,” Trans. Linn. Soc. (1898); W.P. Pycraft, “A Contribution towards our Knowledge of the Pterytography of the Megapodii,” Report Willey’s Zoological Results, pt. iv. (1900); W.P. Pycraft, “Nestling Birds and some of the Problems they Present,” British Birds (1907).
On Pterylosis.—H. Gadow, “Remarks on the Numbers and on the Phylogenetic Development of the Remiges of Birds,” Proc. Zool. Soc. (1888); Z. Gerbe, “Sur les plumes du vol et leur mue,” Bull. Soc. Zool. France, vol. ii. (1877); J.G. Goodchild, “The Cubital Coverts of the Euornithae in relation to Taxonomy,” Proc. Roy. Phys. Edinb. vol. x. (1890-1891); Meijere, “Über die Federn der Vögel,” Morphol. Jahrb. xxiii. (1895); P.C. Mitchell, “On so-called ‘Quintocubitalism’ in the Wing of Birds,” Journ. Linn. Soc. Zool. vol. xxvii. (1899); “On the Anatomy of the Kingfishers, with special reference to the Conditions known as Eutaxy and Diastataxy,” Ibis (1901); C.L. Nitzsch, “Pterytography,” Ray Soc. (1867); W.P. Pycraft, “Some Facts concerning the so-called ‘Aquintocubitalism’ of the Bird’s Wing,” Journ. Linn. Soc. vol. xxvii.; C.J. Sundevall, “On the Wings of Birds,” Ibis (1886); R.S. Wray, “On some Points in the Morphology of the Wings of Birds,” Proc. Zool. Soc. (1887).
(W. P. P.)