The present bird, to which I have assigned the specific term of _maculatus_ has always been a source of perplexity to me, from the circumstance of its varying considerably in its markings; after mature consideration, however, I am induced to regard the specimens from South Australia, Western Australia and the north coast as referable to one and the same species, each however possessing trivial differences by which it may be known from whence it was received. Specimens from the Houtman’s Abrolhos are of a rather smaller size, of a much greyer tint on the back, and have much darker-coloured legs. I believe that the bright yellow wash on the under surface of some individuals is characteristic of newly moulted or young birds: in this species, not only is the throat spotted with black, but the spotting extends over the chest and some distance down the flanks; it has at all times the tail tipped with white, a character which serves at once to distinguish it from _S. osculans_ and _S. frontalis_. Scrubby places, and ravines covered with dense herbage, whether in sterile or humid situations, are its favourite resort. It has the same shy disposition and retiring habits as the other members of the genus, depending for safety rather upon its creeping, mouse-like habits than upon its powers of flight, which are indeed seldom resorted to. Its note is a harsh, grating kind of twitter, often repeated. The nest is a warm, dome-shaped structure, formed of leaves and grasses, and lined with feathers; the eggs are reddish white, minutely freckled and streaked with reddish brown, particularly at the larger end; they are three in number, nine lines long by seven lines broad. All the upper surface, wings and tail brown; the latter crossed near the tip with a broad band of blackish brown, and the outer feathers slightly tipped with white; forehead and lores deep black; stripe above and a small patch below the eye white; spurious wing-feathers black, margined on their inner web with white; under surface in some specimens greyish white, in others washed with yellow; the feathers of the throat and chest spotted with black on a light ground; irides greenish white. The female is somewhat smaller than her mate, and has the lores brown instead of black; in other respects her plumage is very similar to that of the male. The upper figure in the accompanying Plate represents a female, and the lower probably a young male; the figures are of the natural size, from specimens killed in Southern and Western Australia. [Illustration: ACANTHIZA MAGNIROSTRIS: _Gould_. _J. Gould and H. C. Richter del et lith._ _Hullmandel & Walton Imp._ ] SERICORNIS MAGNIROSTRIS, _Gould_. Large-billed Sericornis. _Acanthiza magnirostra_, Gould in Proc. of Zool. Soc., Part V. p. 146; and in Syn. Birds of Australia, Part IV.