The _Calyptorhynchi_ are strictly arboreal, and are evidently formed to live upon the seeds of the _Banksiæ_, _Eucalypti_, and other trees peculiar to the country they inhabit; they diversify their food by occasionally devouring large caterpillars; as they mostly move about in small companies of from four to six in number they can scarcely be considered gregarious. Their flight is rather powerful, but at the same time laboured and heavy; and their voice is a low crying call, totally different from the harsh screaming notes of the _Cacatuæ_. Each division of the country, from the north coast of the continent to Van Diemen’s Land, is inhabited by its own peculiar species. I have never seen a member of this genus from any other country than Australia, but I have heard that an extraordinary Parrot, said to be larger than any at present in our collections, inhabits New Guinea, and which, from the description given of it, will probably be of this form. The _Calyptorhynchi_ lay from two to four eggs in the holes of trees. 368. Calyptorhynchus Banksii Vol. V. Pl. 7. 369. Calyptorhynchus macrorhynchus, _Gould_ Vol. V. Pl. 8. Inhabits the north coast, where it represents the _C. Banksii_ of the eastern and the _C. naso_ of the western coasts. 370. Calyptorhynchus naso, _Gould_ Vol. V. Pl. 9. This species, which is confined to Western Australia, is rendered conspicuous by the small size of its crest, and by its bill being nearly as large as that of _C. macrorhynchus_, while its wings are much shorter than those of that species. 371. Calyptorhynchus Leachii Vol. V. Pl. 10. _Banksianus Australis_, Less. Traité d’Orn. p. 180, Atlas, pl. 18, fig. 2, fem. Inhabits the south-eastern parts of the continent, and differs from all the others in its smaller size, the gibbose form of its bill, and in the paucity of its crest. 372. Calyptorhynchus funereus Vol. V. Pl. 11. Confined, I believe, to New South Wales, and South Australia? 373. Calyptorhynchus xanthonotus, _Gould_ Vol. V. Pl. 12. The true habitat of this species is Van Diemen’s Land, but I have lately received a specimen from Port Lincoln, which proves that its range extends to South Australia. It is distinguished from _C. funereus_ by its much smaller size, and by the uniformity of the yellow colouring of the tail. 374. Calyptorhynchus Baudinii, _Vig._ Vol. V. Pl. 13. Inhabits Western Australia, and is distinguished by its small size and by the white marks on the tail. Genus CALLOCEPHALON, _Less._ Of this form only a single species is known. 375. Callocephalon galeatum Vol. V. Pl. 14. Inhabits the southern coast of Australia and Van Diemen’s Land. Genus POLYTELIS, _Wagl._