The discovery of this remarkable and highly interesting Australian species is due to Allen Cunningham, Esq. who, on an inland expedition ordered by our government, in 1827, discovered it in small flocks on the arid sandy plains between Lat. 29 and 28, 50. Long. 150¾ E. We must again express our public thanks to this intelligent and liberal naturalist for the ornithological specimens then collected. Among these were two skins of the bird in question; but as the mere addition of a new species to our already overwhelming list would be of little importance to the philosophy of the science, we have hitherto refrained from publishing it. In truth, the natural affinities of this extraordinary Cockatoo-Parrakeet called for a much deeper investigation of the whole family than it had yet received, nor are we ashamed to confess that nearly five years elapsed before we could partially accomplish this, with any thing like satisfactory results. But we regret not the delay, since it is obvious that the illustration of such an apparently anomalous form as this, is infinitely more useful to science than the specification, _in a few lines_, of a hundred new species, or even of as many new genera, unaccompanied by analytical or comparative results. The time, in fact, is now gone by, when such crude additions to ornithological nomenclature, possess any claim to permanent interest, or carry with them any authority: they encumber rather than advance science, by keeping up the already overwhelming stock of undigested materials. Mr. Lear has recently given beautiful figures of this species, but under the peculiarly inappropriate name of _Palæornis Novæ-hollandiæ_. The genus is _Platycercus_, _all_ the species of which are from New Holland, excepting those of the Fissirostral type. The exactness of our figure renders a detailed account of its plumage unessential. * * * * * * [Illustration: MUREX (_Centronotus_) _radix_.] MUREX (_Centronotus_) radix, _Porcupine Murex._ ---- Genus Murex. Sub-genus Centronotus. _Nob._ SUB-GENERIC CHARACTER. See pl. 100. ---- SPECIFIC CHARACTER. _Shell ovate globuse, transversely grooved; with numerous varices, armed with compressed, spine-like foliations: colour white; the spines, base, and inner lip black._ Murex radix. _Gm. 3527. Lam. Syst. 7. 168._ ---- Centronotus _radix_ was formerly a shell of excessive rarity, but many specimens have latterly been brought from Panama; one of these, obligingly lent to us by Mr. Cummin, we have here figured of the natural size.