The _Calyptorhynchus Leachii_ is the least species of the genus yet discovered, and independently of its smaller size, it may be distinguished from its congeners by the more swollen and gibbose form of its bill. Its native habitat is New South Wales and South Australia. I obtained specimens of it on the Lower Namoi, more than three hundred miles in the interior; and the cedar brushes of the Liverpool range, Mr. Charles Throsby’s park at Bong-bong, and the sides of the creeks of the Upper Hunter, were also among the places in which I killed it. So invariably did I find it among the _Casuarinæ_, that those trees appeared to be as essential to its existence as the _Banksiæ_ are to that of some species of Honey-eater. The crops of those I killed were invariably filled with the seeds of the trees in question. Its disposition is less shy and distrusting than those of the _Calyptorhynchi Banksii_ and _funereus_, but little stratagem being required to get within gun-shot; when one is killed or wounded, the rest of the flock either fly around or perch on the neighbouring trees, and every one may be procured. It has the feeble, whining call of the other members of the genus. Its flight is laboured and heavy; but when it is necessary for it to pass to a distant part of the country, it mounts high in the air and sustains a flight of many miles. It is not unusual to find individuals of this species with yellow feathers on the cheeks and other parts of the head; this variation I am unable to account for; it is evidently subject to no law, as it frequently happens that six or eight may be seen together without one of them exhibiting this mark, while on the contrary a like number may be encountered with two or three of them thus distinguished. To this circumstance, and to the variation in the colouring of the tail-feathers of the two sexes, may be attributed the voluminous list of synonyms pertaining to this species. Why living examples of the members of this genus have not as yet reached Europe, is not easily to be accounted for. I found no difficulty in keeping a winged bird alive for a short time, and I doubt not that were the attempt made, it might be easily introduced to our aviaries; the real cause probably is the extreme difficulty of procuring young individuals, the breeding-place selected by the bird being holes in the highest trees situated in the most remote parts of the forests, where none but the Aborigines are likely to discover or able to procure them. There is no doubt that Mr. Caley is right in the opinion expressed in his notes that this is the _Carat_ of the natives; and he adds that it lays two eggs in the holes of the trees; “does not cut off the branches of trees like the _Cal. funereus_, but cuts off _May-rybor-ro_ and _Mun-mow_ (the fruit of two species of _Persoonia_), without however eating them, before they are ripe, to the great injury and vexation of the natives.”