I have abundant reasons for stating that every portion of Australia yet visited by Europeans is inhabited by members of the genus _Calyptorhynchus_, and that at least six species are now known, each of which has its own peculiar limits, beyond which it seldom or never passes. The present species, which is one of those with which we first became acquainted, and to which, as will be seen above, several specific appellations have been given, is a native of New South Wales, out of which colony I have never known it to occur, its range appearing to be limited by Moreton Bay on the east and Port Philip on the south. It is not unfrequently seen in the immediate neighbourhood of Sydney and other large towns, and it alike frequents the brushes and the more open wooded parts of the colony, where it feeds on the seeds of the _Banksiæ_ and _Casuarinæ_, changing its diet however, as occasion may offer, to caterpillars, particularly those that infest the wattles and other low trees. The facility with which it procures these large grubs is no less remarkable than the structure of the bird’s bill, which is admirably adapted for scooping out the wood of both the larger and smaller branches, and by this means obtaining possession of the hidden treasure. The Banksian Cockatoo is a suspicious and shy bird, and it requires a considerable degree of caution to approach it within gun-shot; there are times however, particularly when it is feeding, when this may be more readily accomplished. It never assembles in large flocks like the White Cockatoo, but moves about either in pairs or in small companies of from four to eight in number. Its flight is heavy, and the wings are moved with a flapping, laboured motion; it seldom mounts high in the air, for although its flight is somewhat protracted, and journeys of several miles are performed, it rarely rises higher than is sufficient to surmount the tops of the lofty _Eucalypti_, a tribe of trees it often frequents, and in the larger kinds of which it almost invariably breeds, depositing its two or three white eggs in some inaccessible hole, spout or dead limb, the only nest being the rotten wood at the bottom, or the chips made by the bird in forming an excavation. The female and young birds of both sexes differ very considerably from the old male in the marking of their plumage, and hence has arisen no end of confusion and the various names assigned to this bird; the above list of synonyms has been worked out with considerable care, and will I believe be found correct.