374 BROOKLYN INSTITUTE .MUSECM. SCIENCE IIULLETIN 2. 6. 
Pliaciluisa maiinirostris Berlepsch & Hartert, p. 132. 
Native name Guanaguanare. 
Eye seal brown; bill canary yellow, lightest at the base; feet sul- 
phur yellow. 
One of the most abundant and characteristic of birds along the 
Orinoco. It is likely to be the first species one will see on entering the 
mouth of the great river, and as he proceeds towards the head-waters 
it will follow him, and even when he crosses through the Cassiquiare and 
down the Rio Negro to the Amazon. 
The nesting season begins in December and lasts until February. 
vStkrn.\ supercieakis Vieillot. 
Sterna supcrciliaris \'ieill., Nou\-. Diet. XXXII. 1819. p. 126; Berlepsch 
& Hartert, p. 132. 
Native name Tciifeii. Not abundant but observed everywhere both 
on the lower and upper stretches of the river. Fresh birds have the eye 
seal brown ; bill dark Naples yellow ; feet dusky suli)hur yellow. 
RVNCHOPS NIGRA CINERASCENS (Spix). 
Rhynchops cincrascens Spix, .\v. Bras. II. 1825. p. 80, PI. 102. 
Rhynchops nigra cincrascens Berlepsch & Hartert, p. 132. 
Native name Gaviota. Connnon all along the middle and lower 
stretches of the river. 
Larus atricilla (Linnaeus). 
Lams atricilla Linn., Syst. Xat. I, 1758, p. 136 (Bahamas). 
Often seen in company with the Large-billed Tern (Phaethusa 
cliloropoda) about the mouths of the Orinoco and common at almost 
all points along the shore of the Bay of Paria. 
