Perhaps no bird has more divided the opinion of ornithologists, as to the situation it should occupy in the natural system, than the one here represented; and although more than fifty years have now elapsed since the bird was first discovered, little or no information has been hitherto published respecting its economy and habits, as ornithologists have had only its external structure to guide them in their opinions. Aware of this fact, I paid considerable attention to the subject while in Australia; and after a minute observation of the bird in a state of nature, I am decidedly of opinion, that it has not, as has been very generally considered, the most remote relationship to the _Gallinaceæ_; but that it forms, with the American genera _Pteroptochos_, _Scytalopus_, and their allied groups, a family of the Insessorial Order, to which _Troglodytes_, _Amytis_, _Stipiturus_, _Malurus_, _Dasyornis_ and _Psophodes_ closely assimilate in their habits, and of which they will in all probability be hereafter found to form a part. Notwithstanding the great size of _Menura_ and the extraordinary form of its tail, in almost every other point it presents a striking resemblance to its minute congeners: like them, it possesses the bristles at the base of the bill, but to a less extent, the same unusual mass of loose, flowing, hair-like feathers on the back and rump, the same extraordinary power of running, the like feebleness of flight; all which will, I trust, render it evident that there are sufficient grounds for the opinion I have here expressed. Many intervening genera will, doubtless, yet be discovered to complete the series of affinities: at all events, if, as I am informed is the case, the young of _Menura_ are helpless and blind when hatched, it cannot with propriety be placed with the _Gallinaceæ_. In the structure of its feet, in its lengthened claws, and in its whole contour, the Lyre-bird presents the greatest similarity to the _Pteroptochos megapodius_ of Kittlitz. Another singular circumstance by which their alliance is rendered still more evident, is the fact that _Pteroptochos_ differs from the other families of the Insessorial Order in having fourteen feathers in its tail, and that _Menura_ also differs in the same particular in possessing sixteen. The immense feet and claws of these two birds admirably adapt them for the peculiar localities they are destined to inhabit; and the same beautiful modification of structure is observable in the other genera, equally adapting them for the situations they are intended to fulfil. Thus _Menura_ passes with ease over the loose stones and the sides of rocky gullies and ravines, while the _Maluri_ trip over the more open and even ground, and the _Dasyorni_ with equal facility thread the dense scrubs and reed-beds.