HYLOBATES 149 



FAMILY 4. HYLOBATID/E. 

 GENUS I. HYLOBATES. GIBBONS. 



A- 2—2' ^' 1— li "• 2— 2J "^- 3— 3 "■ J 



HYLOBATES Illig., Prodr. Syst. Mamm. et Avium, 1811, p. 67. Type 



Homo lar Linnaeus. 

 Satyrus Oken, Lehrb. Naturg., 3ter Theil, Zool., 2te Abth., 1816, 



pp. XI, 1225-1227, (nee Meigen 1803 Diptera). 

 Laratus Gray, Lond. Med. Repos., XV, 1821, p. 297. 

 Cheiron Burnett, Quart. Journ. Scien. Lit. and Art, XXVI, 1828, 



p. 307. 

 Brachiopithecus Senechal, Diet. Pitt. Hist. Nat., VIII, Pt. II, 



1839, p. 428. (Part). 



Head small, round ; body slender ; arms very long, the forearm 

 exceeding the arm in length ; thumb and great toe widely separated 

 from the next digits ; great toe well developed, and nearly half as long 

 as the foot ; callosities present ; cheek pouches and tail absent ; skull has 

 large orbits ; supraorbital ridges prominent ; canines large ; cusps of 

 molars not forming transverse ridges ; last lower molar without pos- 

 terior talon; vermiform appendage present; sternum consisting of a 

 manubrium and a single bone only ; ribs usually seven, but sometimes 

 eight pairs. 



Of all the Anthropoids the Gibbons are farthest removed from 

 man. They are well named Hylobates or Tree-walkers, for their lives 

 are passed upon trees, through whose branches they move with 

 the ease and swiftness of a bird, but are practically helpless on the 

 ground, over whose surface they progress awkwardly and with no 

 little difficulty, balancing themselves by holding the long arms above 

 the head and hastening forwards as rapidly as possible in order to 

 maintain an equilibrium. But let one of the long slim hands touch a 

 bough of some low tree and how marvellous the change ; the struggling 

 animal of earth becomes endowed with flying powers, and in many a 

 graceful sweep and an amazing accuracy of aim, it passes with in- 

 credible speed through the forest, holding its course from bough to 



