The only known species of this remarkable form inhabits the eastern parts of Australia, and according to information derived from the notes made by Mr. Gilbert during Dr. Leichardt’s Expedition, extends its range northward from thence to within the tropics. I have recently had a young specimen presented to me by Lady Dowling, one of two taken from a branch of a tree while being fed by birds not of its own species, an important fact as showing the parasitic habits of the bird. 344. Scythrops Novæ-Hollandiæ, _Lath._ Vol. IV. Pl. 90. Genus EUDYNAMYS, _Vig. & Horsf._ One species only of this form inhabits Australia; others are found in the Indian Islands and on the continent of India. 345. Eudynamys Flindersii Vol. IV. Pl. 91. Genus CENTROPUS, _Ill._ On reference to my account of the _Centropus Phasianus_, it will be seen I have stated that some variation exists in the form of the bill in specimens from different localities, intimated a belief of there being more than one species, and remarked that should such prove to be the case, the term _macrourus_ might be applied to the Port Essington birds, and _melanurus_ to those from the north-west coast; and these names are provisionally given until future research has proved whether they be or be not distinct. 346. Centropus Phasianus Vol. IV. Pl. 92. 347. Centropus macrourus, _Gould_. 348. Centropus melanurus, _Gould_. Family CERTHIADÆ, _Vig._ Genus CLIMACTERIS, _Temm._ Several species of this well-defined and singular group of Australian birds have lately been discovered; two out of the six now known are all that had been described prior to the publication of the present work. With the exception of Van Diemen’s Land and the Cobourg Peninsula, every colony is inhabited by one or other of the following species:— 349. Climacteris scandens, _Temm._ Vol. IV. Pl. 93. 350. Climacteris rufa, _Gould_ Vol. IV. Pl. 94. 351. Climacteris erythrops, _Gould_ Vol. IV. Pl. 95. 352. Climacteris melanotus, _Gould_ Vol. IV. Pl. 96. 353. Climacteris melanura, _Gould_ Vol. IV. Pl. 97. 354. Climacteris picumnus, _Temm._ Vol. IV. Pl. 98. _Certhia leucophæa_, Lath. Gen. Hist., vol. iv. p. 182. Genus ORTHONYX, _Temm._ Much difference of opinion has arisen among ornithologists respecting the situation of this bird in the natural system, and as to what genus it is most nearly allied; I regret to say that not having seen much of it in its native wilds, I am unable to clear up these disputed points. The form is strictly Australian, and the single species known is confined to the south-eastern part of the country. 355. Orthonyx spinicaudus, _Temm._ Vol. IV. Pl. 99.