XXXIX. ANATINÆ. DUCKS, 267 1. Phœnicopterus. Flamingo, 268 2. Anser. Goose, 270 3. Cygnus. Swan, 273 4. Anas. Duck, 275 5. Fuligula. Sea-Duck, 284 XL. MERGINÆ. MERGANSERS, 298 1. Mergus. Merganser, 297 XLI. PELECANINÆ. PELICANS, 300 1. Phalacrocorax. Cormorant, 301 2. Plotus. Anhinga, 305 3. Tachypetes. Frigate Bird, 306 4. Pelecanus. Pelican, 308 5. Sula. Gannet, 310 6. Phaeton. Tropic Bird, 312 XLII. LARINÆ. GULLS, 313 1. Rhynchops. Skimmer, 313 2. Sterna. Tern, 315 3. Larus. Gull, 322 XLIII. PROCELLARINÆ. FULMARS, 330 1. Lestris. Jager, 331 2. Diomedea. Albatross, 333 3. Procellaria. Fulmar, 335 4. Puffinus. Shearwater, 337 5. Thalassidroma. Petrel, 339 XLIV. ALCINÆ. AUKS, 341 1. Mormon. Puffin, 342 2. Alca. Auk, 344 3. Phaleris. Phaleris, 345 4. Mergulus. Sea-Dove, 348 5. Uria. Guillemot, 349 XLV. COLYMBINÆ. DIVERS AND GREBES, 351 1. Colymbus. Diver, 352 2. Podiceps. Grebe, 355 SYNOPSIS. FAMILY I. VULTURINÆ. VULTURINE BIRDS, OR VULTURES. Bill of moderate length, stout, cerate; upper mandible with the tip elongated and decurved; lower mandible rounded and thin-edged at the end. Head rather small, or of moderate size, ovato-oblong, and with part of the neck destitute of feathers. Eyes of moderate size, without projecting ridges. External aperture of ears rather small and simple. Skin over the fore part of the neck bare or merely downy. Tarsus rather stout, bare, and shorter than the middle toe; hind toe much smaller than the second; anterior toes connected at the base by a web; claws large, moderately curved, rather acute. Plumage full and rather compact. Wings very long, subacuminate. Œsophagus excessively wide, and dilated into a crop; stomach rather large, somewhat muscular, with a soft rugous epithelium; intestine of moderate length and width; cœca extremely small. The young when fledged have the head and upper part of the neck generally covered with down. Eggs commonly two. GENUS I. CATHARTES, Illiger. TURKEY-VULTURE.