Part 36

Saimiris usta, Is. Geoffr., Arch. Mus., iv., p. 15, pl. 1 (1844).

Saimiris ustus, Bartlett, P. Z. S., 1871, p. 219; Sclater, P. Z. S., 1872, p. 688, fig. of head.

Chrysothrix ustus, Gray, Cat. Monkeys Brit. Mus., p. 53 (1870).

Saimiri sciureus (nec L.), Schl., Mus. Pays Bas, vii., p. 242 (1876, pt.)

CHARACTERS.--Face white; head grizzled grey, minutely punctulated with black, the hairs grey with black tips; outer side of fore-arm grizzled grey, but in some species golden; back {155}grizzled grey, washed with golden, the tips of the hairs black; tail short, thick and grey, but with the tip black.

DISTRIBUTION.--The forests of Bolivia and Brazil. This is a common species, inhabiting the whole of the Peruvian Amazons, and may be met with on every stream. (E. Bartlett.)

HABITS.--Arboreal and gregarious, moving about in large numbers through the forest, feeding on insects--chiefly orthoptera and spiders--small birds, and fruits.

II. THE BLACK-HEADED SQUIRREL-MONKEY. CHRYSOTHRIX ENTOMOPHAGA.

Callithrix entomophagus, d'Orb., Voy. Amér. Mér., iv., Mamm. pl. 4 (1836).

Callithrix boliviensis, d'Orb., Nouv. Ann. Mus., iii., p. 89 (1834).

Saimiris entomophagus, d'Orb., Voy. Amér. Mér., iv., Mamm., text, p. 10 (1847); Is. Geoffr., Cat. Méth. Primates, p. 38 (1851).

Saimiri entomophagus, Schl., Mus. Pays Bas, vii., p. 246 (1876).

Chrysothrix sciurea (nec L.), Frantz. in Wiegm. Arch. f. Nat., xxxix., p. 260 (1869).

Chrysothrix entomophagus, Wagn., Ann. Nat. Hist., xii., p. 42 (1843); Gray, Cat. Monkeys Brit. Mus., p. 53 (1870).

CHARACTERS.--Face grey, washed with yellow; ears haired; head black; hairs of back black, with long yellow tips, or yellow with black tips, producing a shade of brown washed with golden; outer side of upper part of arms and legs yellow, peppered with black; throat, under surface of body and inside of limbs yellowish-grey; tail long, black.

{156}In some species the upper part of the head has a shade of yellow, caused by the colour of the lower half of the hairs showing through the black tips.

DISTRIBUTION.--Bolivia; Veragua, Central America; and the warmer regions of Costa Rica, where it inhabits the humid forests.

III. THE COMMON SQUIRREL-MONKEY. CHRYSOTHRIX SCIUREA.

Simia sciurea, Linn., Syst. Nat., i., p. 43 (1766); Humb., Obs. Zool., p. 334 (var. cassiquiarensis).

Callithrix sciureus, Geoffr., Ann. Mus., xix., p. 113 (1812).

Saimiri sciureus, Cuv., Reg. An., p. 103, pl. 1 (1829); Schl., Mus. Pays Bas, vii., p. 242 (1876).

Chrysothrix lunulata, Geoffr., Arch. Mus., iv., p. 18 (1844).

Chrysothrix sciurea, Wagner in Schreb., Säugth. Suppl., v., p. 120, pl. 9, (1855); Gray, Cat. Monkeys Brit. Mus., p. 53 (1870); Sclater, P. Z. S., 1880, p. 395.

Chrysothrix nigrivittata, Wagn., Abh. bay. Ak. München, v., p. 461.

CHARACTERS.--Smaller than the two preceding species; face greyish-white; chin round and prominent; head blackish-grey; back grey, or grey washed with gold, the basal part of the hairs golden and the tips black; outer side of the fore-arm yellow; tail long, slender, grizzled grey, with the tip black. Length of the body, 10 inches; of the tail, 14 inches.

Certain females, examined by Dr. Sclater, had a distinct black line along the side of the crown above each ear and extending in front, down the side of the face, nearly to a level {157}with the angle of the mouth; but Mr. Buckley says the Indians consider the black lines to be merely a sign of age.

DISTRIBUTION.--This species has an extensive range, being found on both banks of the Amazon, Rio Negro, and on the Copataza river; also in Guiana, Surinam, and Colombia, near Bogotá.

HABITS.--Like its congeners, the Common Squirrel-Monkey is arboreal, going about in large flocks. Their food consists of insects and fruits. Mr. Bates observes that the "pretty little Chrysothrix sciureus contents itself with devouring what fruit it can on the spot," thus differing from certain species of Cebus, which destroy more than they eat, and when about to return to the forest, carry away all they can in their hands or under their arms.