_Haliaëtus (Ictinoaëtus) leucosternon_, Kaup, Isis, 1847, p. 277. Confined, so far as I am aware, to Australia, and forming a beautiful representative of the _Haliastur Ponticerianus_ of India. 5. Haliastur sphenurus Vol. I. Pl. 5. _Milvus sphenurus_, Swains. Class. of Birds, vol. ii. p. 211. _Haliaëtus (Ictinoaëtus) canorus_, Kaup, Isis, 1847, p. 277. Inhabits all parts of Australia yet visited by travellers, even the Depôt in the interior. Genus PANDION, _Sav._ Of the genus _Pandion_ four species are now known; one inhabiting America, another Europe and Asia, a third the Indian Islands, and the fourth Australia. 6. Pandion leucocephalus, _Gould_ Vol. I. Pl. 6. _Pandion Gouldii_, Kaup, Isis, 1847, p. 270.—List of Birds in Brit. Mus. Coll., Part I. 2nd edit. p. 22. This species of _Pandion_ performs precisely the same office in Australia that the _P. haliaëtus_ does in Europe and the _P. Carolinensis_ in America; to both of which species it is very nearly allied. Genus Falco, Linn. As they are the most typical of all the Hawks, so are the members of the genus _Falco_ the most universally dispersed over the face of the globe; and I question whether the law of representation is in any case more beautifully and clearly shown than by the members of the present group. 7. Falco hypoleucus, _Gould_ Vol. I. Pl. 7. Up to the present time only four examples of this fine Falcon have been procured; it is a species admirably adapted for the sport of Falconry, and is a beautiful representative of the _Falco Gyrfalco_ of Europe. Its native habitat is the interior of the southern and western portions of Australia. 8. Falco melanogenys, _Gould_ Vol. I. Pl. 8. _Falco macropus_, Swains. Anim. in Menag., p. 341. —— _melanogenys_, Kaup, Isis, 1847, p. 75. India, Europe, and North America on the one hand, and Cape Horn, the Cape of Good Hope and Australia on the other, are all inhabited by Falcons so nearly allied to each other as to favour the opinion that they are merely varieties of each other; but I agree with the Prince of Canino and Professor Kaup in considering them to be distinct and representatives of each other in the respective countries they inhabit. It will doubtless be found that the habits and economy of the whole are as similar as they are in outward appearance; and that the _Falco melanogenys_ is as destructive to the ducks of the interior of Australia as the _Falco Anatum_ is in North America. 9. Falco subniger, _Gray_ Vol. I. Pl. 9. A powerful Falcon differing somewhat in structure from the _F. hypoleucus_ and _F. melanogenys_. Nothing is known of its habits, and as yet I have only seen four examples, all of which were procured in the interior of South Australia.