I procured a specimen of this bird from the Rio Negro in Northern Patagonia, and I never saw one any where else; and M. D’Orbigny makes the same remark. On the Atlantic side of the continent, it replaces the several species of _Pteroptochos_ which live on the shores of the Pacific. Its habits, in some respects, are similar; it lives at the bottom of hedges or thickets, where it runs with such quickness, that it might easily be mistaken for a rat. It is very unwilling to take flight, so that, I was assured by some of the inhabitants, that it could not fly, which, however, is a mistake. It frequently utters a loud and very singular cry. The Rhinomya is distantly allied to the _Eremobius phœnicurus_, which is found in Southern Patagonia, whose habits in some respects are similar. 1. PTEROPTOCHOS TARNII. _G. R. Gray._ Hylactes Tarnii. _Vigors_, Proc. Zool. 1830. Megalonyx ruficeps. _D’Orb. & Lafr._ Mag. de Zool. 1837. p. 15. Leptonyx Tarnii. _D Orb. & Lafr._ Voy. de l’Amer. Mer. Av. p. 198, pl. viii. f. 1. This species, as well as several others of the genus, and likewise of Scytalopus are confined to the west coast of South America. The _P. Tarnii_ ranges from the neighbourhood of Concepcion, lat. 37°, to south of the Peninsula of Tres Montes, between 41° and 50°. It is not found in Tierra del Fuego, where the climate probably is too cold for it, for in other respects, the great forests of that country appear admirably adapted to its habits. Its limit, northward of the province of Concepcion, is evidently due to the change which there takes place, from dense forests to an open and dry country. The _P. Tarnii_ is abundant in all parts of the Island of Chiloe, where it is called by the native Indians, _guid-guid_; but by the English sailors, the barking-bird. This latter name is very well applied, for the noise which it utters is precisely like the yelping of a small dog. When a person is walking along a pathway within the forest, or on the sea beach, he will often be surprised to hear on a sudden, close by him, the barking of the _guid-guid_. He may often watch in vain the thicket, whence the sound proceeds, in hopes of seeing its author, and if he endeavour, by beating the bushes, to drive it out, his chance of success will be still smaller. At other times, by standing quietly within the forest, the _guid-guid_ will fearlessly hop close to him, and will stand on the trunk of some dead tree, with its tail erect, and strange figure full in view. It feeds exclusively on the ground, in the thickest and most entangled parts of the forest. It rarely takes wing, and then only for short distances. It has the power of hopping quickly and with great vigour; when thus awkwardly proceeding, it carries its short tail in a nearly erect position. I was informed that the _guid-guid_, builds a nest amongst rotten sticks, close to the ground. 2. PTEROPTOCHOS MEGAPODIUS. _Kittl._