_Hab._ Patagonia, Chili, Peru, Argentina, Brazil, and Falkland Islands, up to Rio. This is a black-headed Tern with a blood-red bill, which is found abundantly on the coast of Patagonia, and extends up the Atlantic coast to Rio. It was noticed by Durnford near Buenos Ayres, and found breeding by the same excellent observer at Tombo Point, about sixty miles to the south of Chupat, in December 1877. He tells us:-- "I was prepared when I visited this place in December to see a considerable quantity of birds; but the number that met my eyes fairly staggered me. Their nests covered an area about 150 yards square. Allowing three nests and five eggs for every square yard (a very moderate computation, it being difficult to walk without treading on the eggs), we arrive at the extraordinary number of 67,500 nests, 135,000 birds, and 112,500 eggs; and, wonderful as these figures may appear, I feel sure that I have rather understated than overstated the numbers. The nests were mere hollows in the fine gravel or shingle, and contained one, two, and sometimes three eggs. The latter generally have the appearance of the eggs of the Sandwich Tern, though of course smaller; and out of many hundreds I did not see two alike." 415. STERNA SUPERCILIARIS, Vieill. (EYEBROWED TERN.) +Sterna superciliaris+, _Scl. et Salv. Nomencl._ p. 147; _iid. P. Z. S._ 1871, p. 571; _Durnford, Ibis_, 1877, p. 201 (Buenos Ayres); _White, P. Z. S._ 1882, p. 628 (Misiones); _Saunders, P. Z. S._ 1876, p. 662. +Sterna argentea+, _Burm. La-Plata Reise_, ii. p. 519 (Paraná). _Description._--Forehead and underparts white; loral stripe, head, and nape black; back, rump, inner primaries, and inner web of tail pale slate-grey; outer primaries blackish; bill yellow; legs and feet olive-yellow: whole length 8·5 inches, wing 7·0. In the young bird the crown is grey. _Hab._ The large rivers and the coast on the east side of South America. This is a little Tern, belonging to the same group as the European _Sterna minuta_, with a uniform pale yellow bill. Durnford met with it at Baradero, and says that it frequents shallow inland lagoons and small streams, but is also found on the Rio de la Plata. Dr. Burmeister obtained it on the Paraná, and White at Itapua, Misiones. Saunders shot it on the Huallaga, in Peru, 2800 miles inland. 416. LARUS DOMINICANUS, Licht. (DOMINICAN GULL.) +Larus dominicanus+, _Scl. et Salv. Nomencl._ p. 148; _iid. P. Z. S._ 1871, p. 576; _Durnford, Ibis_, 1877, p. 45 (Chupat) et p. 201 (Buenos Ayres), et 1878, p. 405 (Chupat); _Barrows, Auk_, 1884, p. 316 (Pampas); _Saunders, P. Z. S._ 1878. p. 180; _Withington, Ibis_, 1888, p. 472 (Lomas de Zamora). +Larus vociferus+, _Burm. La-Plata Reise_, ii. p. 518 (Buenos Ayres).