Young.—Similar in colour to the adults, but lighter; the frontal band yellow, not white; limbs light yellow.
Varieties.—Several varieties of this species—the "Simpona" of the natives—have been described, of which the following deserve special notice:—
THE SILKY SIFAKA. PROPITHECUS SERICEUS.
Face black, with flesh-coloured spots; the body entirely white, faintly washed with yellow; the base of the tail washed with rust-red. It is of the same size as the type-form, and appears to be only an albino variety. Specimens showing every gradation in coloration between that of the type and the absolute albino are now well known. This form, however, is more or less restricted to the narrow belts of forest on the eastern side of the mountains in the north-east of Madagascar, between the rivers Lokoi and Bemarivo, a region conterminous with that inhabited by the typical species.
MILNE-EDWARDS' SIFAKA. PROPITHECUS EDWARDSI.
Differs from the true P. diadema in having the face slightly haired between the eyes and on the chin; a patch on each flank rufous-white or orange-yellow, separated by a reddish-black band; a spot at the root of the tail bright rusty-red, and all the rest of body black, washed slightly with rufous. The young are like the parents. This form is also of the same size as the type, but is a melanistic variety, for a series of specimens show every intermediate shade between that here described and the Black Sifaka (P. holomelas), which is of an entirely black colour, and inhabits, as has been shown by MM. Milne-Edwards and Grandidier, the same region as P. edwardsi.
Distribution.—The typical form of the species is confined to the extended region on the east coast of Madagascar lying between the Bay of Antongil on the north, and the River Masora in the south, in the forest-belts on the eastern aspect of the mountains, where rain falls abundantly and the whole region is covered with luxuriant vegetation. Its melanistic variety (P. edwardsi) extends south from the Masora as far as the Faraouny river, but it ranges to higher and colder altitudes on the mountains; while its albinistic variety (P. sericeus) lives in the somewhat warmer region to the north of Antongil Bay, each being, to south and north respectively, conterminous with the central habitat of the typical form.
II. VERREAUX'S SIFAKA. PROPITHECUS VERREAUXI.
Propithecus verreauxi, Grandid., Album de l'île de la Réunion, iv., pp. 153-162, pls. 1, 2 (1867); Milne-Edwards and Grandid., Hist. Nat. Madag., Mamm., i., p. 305 (with full synonymy), Atlas, pls. 4, 6, 8.
Characters.—Fur short and woolly; face entirely naked; head longer than broad; a well-marked swelling of the skull between the eyes; the upper incisors sub-equal. Smaller and more robust than P. diadema, the head longer, the hair on the limbs shorter, the tail longer.