I procured specimens of this bird from Bahia Blanca, in Northern Patagonia, from Tierra del Fuego, from Chiloe, and from Central and Northern Chile. It is everywhere common. It frequents open places; so that in the wooded countries it lives entirely on the sea beaches, or near the summits of mountains, where trees do not grow. In the excessively sterile upper valleys of the Cordillera of Northern Chile I met with this bird, even at a height of little less than ten thousand feet, where the last traces of vegetation occur, and where no other bird lives. It generally moves about in very small flocks, and frequents rocky streams and marshy ground: it hops and flies from stone to stone, very much after the manner of our whinchat (_Motacilla rubetra_), but when alighting it frequently expands its tail like a fan. The sexes are exactly similar in size and plumage. Mr. G. R. Gray observes, that the genus Muscisaxicola is probably synonymous with Lessonia of Mr. Swainson; but the latter name cannot be used, as it has already been twice employed in other branches of Natural History. 2. MUSCISAXICOLA MACLOVIANA. _G. R. Gray._ Sylvia macloviana, _Garn._ Voy. de la Coqu. Zool. p. 663. Curruca macloviana, _Less._ I brought home only one specimen of this bird; it came from East Falkland Island, whence also those described by Messrs. Lesson and Garnot were procured. Mr. Gould considered it a distinct species, but having carefully compared it with _M. mentalis_, I can see not the smallest difference in any point, excepting that it is somewhat larger in all its dimensions. The length of the whole body is .6 of an inch greater, of wing when folded .45, of tarsus .2, greater than in the foregoing species. I can scarcely hesitate in thinking it a large-sized local variety, from some favourable condition in the Falkland Islands to its growth. 3. MUSCISAXICOLA BRUNNEA. _Gould._ _M. griseo-fusca; gutture abdomineque albis flavescenti tinctis, pectore obscuro; alis caudâque obscure fuscis, singulis plumis rufescenti-fusco marginatis; rectricum externarum radiis lateralibus flavescentibus._ Long. tot. 5 unc.; _rostri_, ¹¹⁄₁₆; _alæ_, 3⅛; _caudæ_, 2⁴⁄₈; _tarsi_, 1. Head, and all the upper surface greyish brown; wings and tail dark brown, each feather margined with reddish brown; the outer webs of the external tail feathers buffy white; throat and all the under surface white, slightly tinged with buff; bill and feet blackish brown. Habitat, Port St. Julian, Patagonia. (_January_). The only specimen I procured was immature. 4. MUSCISAXICOLA NIGRA. _G. R. Gray._