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 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.