These birds are not uncommon on the dry rocky mountains near Valparaiso, and in the valleys of southern Patagonia, where a few thickets grow. They hop actively about the withered herbage and low thickets, and often feed on the ground. The hind claw is weaker and straighter than in most of the other species of this genus. 4. SYNALLAXIS MALUROIDES. S. maluroides. _D’Orb. & Lafr._ Voy de l’Amer. Mer. Ois. pl. xiv, f. 2. Mag. de Zool. 1837, Cl. 11, pl. 22. My specimens were shot near Maldonado. Iris yellow; tarsi very pale coloured. This species, as well as some others of Synallaxis, Anumbius, and Limnornis, live amongst reeds and other aquatic plants on the borders of lakes, and have the same general habits. I will, therefore, here describe them. They all have the power of crawling very quickly by the aid of their powerful claws and feet, as I soon discovered when they were not killed at once, for then it was scarcely possible to catch them. Their soft tail-feathers show signs of being used, but they never apply them, as the Certhias do, as a means of supporting their bodies. The tail-feathers were (at least during June) so loosely attached, that I seldom procured a specimen with all of them perfect; and I saw many (especially of _S. maluroides_), flying about with no tail. All the species, or nearly all, utter an acute, but not loud, rapidly reiterated cry. They are active and busily seek for small insects, chiefly Coleoptera, in the coarse herbage. The iris in all is rusty red; the tongue is divided and terminates in bristly points. These reed birds, which are very numerous both in species and individuals, on the borders of lakes in the provinces north of the Plata, appear to supply in South America, the various Sylviæ, which frequent similar stations in Europe. 5. SYNALLAXIS FLAVOGULARIS. _Gould._ PLATE XXIV. _S. supra fuscescenti cinereus, infra cinereo-fuscus; remigibus obscurè fuscis, basi obscurè rufis; caudæ plumis sex mediis nigro-fuscis, externis ferrugineis; genis gulâque flavescentibus, plumis singulis apice obscurè fuscis._ Long. tot. 6½ unc.; _rost._ ¾;l _alæ_, 2½; _caudæ_, 3⅝; _tarsi_, ¾. Head and all the upper surface, brown; primaries, dark brown, with the basal portions rufous; six central tail-feathers, blackish brown; the remainder ferruginous; sides of the face and throat yellowish, with the tip of each feather dark brown; the remainder of the under surface, greyish brown; bill and feet, dark brown. Habitat, Patagonia. My specimens were obtained at Bahia Blanca and at Santa Cruz, two extreme parts of Patagonia. It frequents the thinly scattered thickets on the arid plains: the hind claw of its foot is not produced as in _S. rufogularis_, and it lives less on the ground. 6. SYNALLAXIS BRUNNEA. _Gould._