_Description._--Above dark greyish; front of head and neck behind pale cinereous; back of head and upper part of neck black; ear-coverts considerably elongated, golden brown: beneath, throat grey, paler than front of head; rest of under surface shining white; primaries greyish brown, the innermost tipped with white; secondaries more or less pure white, or dusky on outer webs: whole length 11·5 inches, wing 4·7. _Female_ similar. _Hab._ Antarctic America, north to Cordova. Darwin obtained examples of this beautiful Grebe at Bahia Blanca, where, he says, "it lives in small flocks in the salt-water channels extending between the great marshes at the head of the harbour." Durnford procured specimens on both visits to Chupat, where he found it common in the lagoons in all the valleys. It is also found, though not so abundantly, in the northern provinces of the Argentine Republic. White obtained a single example at Cosquin, near Cordova, in September 1882. 421. PODICEPS ROLLANDI, Quoy et Gaim. (ROLLAND'S GREBE.) +Podiceps rollandi+, _Scl. et Salv. Nomencl._ p. 159; _iid. Ex. Orn._ p. 190; _iid. P. Z. S._ 1868, p. 146; _Scl. P. Z. S._ 1872, p. 549 (Rio Negro); _Durnford, Ibis_, 1877, p. 45 (Chupat); _Gibson, Ibis_, 1880, p. 164 (Buenos Ayres); _White, P. Z. S._ 1883, p. 43 (Cordova); _Barrows, Auk_, 1884, p. 317 (Bahia Blanca). _Description._--(_Summer plumage._) Above brownish black, with dark green reflexions; all the feathers below the neck narrowly margined with rufous; ear-coverts elongated, white at base with black tips, and more or less covering the downy white feathers of the sides of the head; outer half of primaries brownish grey, darker at tip; inner half and secondaries more or less pure white, some of the outer webs brownish or buff: beneath, neck and throat blackish brown, shading into chestnut, burned with dusky on the lower breast and rest of under surface. (_Winter plumage._) Above not so dark: beneath, throat white, neck dusky rufous; rest of under surface shining whitish buff, becoming dusky towards the vent. Whole length 11·8 inches, wing 5·4. _Hab._ Antarctic America, north to Cordova. Rolland's Grebe is said by Durnford to be "common in almost every pool and ditch" in Chupat. It is also common throughout Buenos Ayres, where the native name for it is _Macasíto_.