a. Entire neck bare; plumage commencing abruptly in a ruff of lanceolate, or penicillate feathers, these continued on the breast and abdomen. Head much elongated, the upper outline a slightly convex plane, the forehead depressed below the level of the very elevated dorsal outline of the cere. Posterior claw very thick and strongly curved.
2. Pseudogryphus. Nostril occupying only the posterior third of the nasal orifice, its anterior end acute. Bill weak, the terminal hook only slightly developed, the mandibles broader than deep, the lower as deep as the upper. Head and neck without corrugations or caruncles. Tarsus slightly longer than the middle toe; fourth or fifth quill longest; extremities of the quills reaching to or beyond the end of the tail. Tail even. (P. californianus.)
b. Only the upper half, or less, of the neck bare; plumage commencing gradually with normal, broad feathers; feathers of breast and abdomen broad and normal. Head only moderately elongated, the upper outline irregular, the forehead elevated above the dorsal outline of the cere. Bill strong, the terminal hook well developed. Posterior claw weaker, less curved.
3. Rhinogryphus. Nostril occupying the whole of the nasal cavity, its anterior end broadly rounded; cere as deep as broad, the upper and lower outlines divergent posteriorly, the former considerably arched; lower mandible much less deep than the upper. Skin of the neck without corrugations; a semicircular tuft of antrorse radiating bristles in front of the eye. Wing very long, the primaries reaching to or beyond the end of the tail. Tail much rounded. (R. aura and R. burrovianus.)
4. Catharista. Nostril occupying only the posterior half of the nasal cavity, its anterior end contracted and acute; cere depressed, much wider than deep, its upper and lower outlines parallel, the former not perceptibly arched; lower mandible as deep as the upper; skin of the neck transversely corrugated; no tuft of bristles in front of the eye. Wing short, the primaries reaching scarcely to the middle of the tail. Tail even, or slightly emarginate. (C. atratus.)
Genus PSEUDOGRYPHUS, Ridgway.
Cathartes, Auct. (in part.)
Gen. Char. Size very large, and aspect vulturine. Head much elongated, with regular outlines; the entire head and neck bare of feathers, the skin faintly wrinkled, but free from corrugations or caruncles. Nostril small, occupying only the posterior third, or less, of the nasal orifice, its anterior end acute. Plumage beginning at the bottom of the neck in a ruff of lanceolate, acuminate feathers, these continued over the breast and abdomen. Wings very large, the primaries and secondaries well developed, the former longest, and reaching to, or beyond, the end of the tail; fourth or fifth quill longest; outer five with inner webs appreciably sinuated. Tail even. Sexes alike.
