Indris variegatus, Gray, Ann. and Mag. N. H. (4), x., p., 474 (1872).
Indris brevicaudatus, Milne-Edwards and Grandid., Hist. Nat. Madag., Mamm., i., p. 336 (with full synonymy), Atlas, pls. xi.-xii.
(Plate XII.)
Characters.—The peculiar features of the species, as given below, are necessarily those of the genus also.
Fur long and woolly, extremely variable in its coloration. Head rounded, longer than it is broad; muzzle moderately long, covered with very short hairs; fingers and toes haired to the finger-tips; external ears rounded, exserted, and more developed than in Avahis or Propithecus, with long and tufted hair forming a fringe all round. Median nose-pad high and narrow; pupil of eye circular; body elongated; arms about one quarter of the length of the legs; hands very long, the four outer fingers united by a membrane as far as the first joint, and the toes to the centre of their middle segments; hands and feet haired to the tips. Tail rudimentary.
Skull longer and less vaulted; brain-case proportionately more compressed from side to side; the muzzle longer, and the orbit smaller, than in Avahis; floor of orbit higher than the bony margin of the jaw; inter-orbital space flat; nasal bones, though long, not extending in front as far as the end of the pre-maxillary bone; mandible elongated, narrower, and less deep than in Avahis. Bony palate short, posterior margin thickened, and with a foramen behind the posterior molar; line of union of the two halves of the lower jaw shorter than in Avahis; its angle very large. No central bone in the wrist (or carpus); hind-limb (with or without the foot), compared with the fore-limb (with or without the hand), longer than in any other of the Primates, except Galago. Upper teeth: Incisors, sub-equal, set close together and subject to variation in size; canine, vertically taller than, and not separated by a gap from, the pre-molar; pre-molars compressed, and having an inner cusp; anterior molars, four-cusped, with the supplementary cusps weak, and with no oblique ridge; anterior and median, with their outer and inner cusps opposite; posterior molar, which is the smallest grinder of the jaw—four-cusped, with transverse, but no oblique ridges. Lower teeth: Incisors, with marked longitudinal ridges to the outside (peculiar to this genus); pre-molars sub-equal; molars all four-cusped, and the posterior ones expanded behind.
Brain highly organised. A large laryngeal pouch (present also in the fœtus), but differing from that of the Apes, is placed between the gullet and windpipe, communicating with the latter by an orifice: main arteries of the fore- and hind-limbs not broken up into a rete mirabile of small parallel vessels, as in many species of Lemurs.
Face naked, sometimes blackish, generally dark grey; lips downy; head, neck, back, shoulders, arms, and hands, deep black; fore-arms faintly washed with rufous; a large patch, widening from the middle of the back downwards to the lower back, rump, and root of the tail pure white, washed with orange or red; a patch on each flank, pale, becoming rufous or greyish-white, separated from the rump-spot by black bands continuing down the outer side of the inner face of the thighs, and the front and inner sides of the legs; thighs ashy-grey, their upper two-thirds greyish, becoming black on the front, and ashy-grey on the hinder surface, of the leg. Feet black; tail stumpy, fawn-colour, brownish-grey at the tip; under side rusty brown; abdomen grey; heel rufous.
Many varieties of this species have been met with. Of these, some have the top of the head and between the eyes greyish-white, mixed here and there with black; jaws and throat, grey; ears, neck, back and upper part of arms, black; the fore-arms grey; the hands black; a patch on the lower back ashy-grey; flanks bright rufous; legs grey; band on front of the thighs black; heel bright rufous.
Other examples have a mark over each eyebrow, the fore-limbs nearly to the hands, the hinder part of the thighs, the legs from the knee to the ankle, and the whole under side iron-grey; the ankles and hind part of the heels white, yellow below. (Indris variegatus, Gray.)