A considerable number of the older-known of the Australian birds have been described in the general works of Vieillot, Latham, Shaw and others; but their descriptions are so vague, and the species themselves so frequently referred to genera widely different from those to which they really belong, that it has been impossible to identify the whole of them; but wherever they could be identified with certainty their names have been adopted, or quoted in the synonyms. The “Birds of Europe” were arranged according to the views of the late Mr. Vigors; and in the “Birds of Australia” the arrangement is mainly the same, with some modifications of my own which appeared to me to be necessary. I have been constrained, for the sake of uniformity in size, to divide the present work into seven volumes; the first of which comprises the RAPTORES, the small number of which will account for its being somewhat thinner than the others; the second, third, fourth, fifth and sixth volumes comprise the INSESSORES, RASORES and GRALLATORES in one continuous series, and the seventh the NATATORES. The following synoptical table will give a general view of the whole; it contains all the additional information I have received, or been able to procure, during the progress of the work; the characters of the new genera I have found it necessary to institute, &c.; and the references to the volumes in which the respective plates are arranged will render it easy to consult and to quote them. Order RAPTORES, _Ill._ Family FALCONIDÆ, _Leach._ Genus AQUILA, _Briss._ Numerous species of this genus exist in Asia and Europe; the form also occurs in Africa, and in North America; so far as I am aware it is not found in South America, and two species are all that are known in Australia. 1. Aquila fucosa, _Cuv._ Vol. I. Pl. 1. _Vultur audax_, Lath. Ind. Orn. Supp., p. ii. _Aquila cuneicaudata_, Brehm, Isis, 1845, p. 356. —— (_Uroaëtus_) _audax_, Kaup, Classif. der Säug. und Vög., p. 12. This fine Eagle ranges over the whole of the southern portion of Australia and Van Diemen’s Land, but I have no positive evidence of its having been seen in the intertropical regions of the country. 2. Aquila Morphnoïdes, _Gould_ Vol. I. Pl. 2. A beautiful representative of the _Aquila pennata_ of Europe and India. Since the discovery of this bird at Yarrundi in New South Wales, when I obtained only a single specimen, T. C. Eyton, Esq. has received a second example in a collection obtained at Port Phillip, and a third was procured by Captain Sturt at the Depôt in South Australia. Genus ICHTHYIAËTUS, _Lafr._