voice, and the common name of the Hoolock is taken from its 

 peculiar double call, which is repeated several times. At a distance 

 the sound much resembles a human voice ; it is a peculiar wailing 

 note, audible from afar, and in the countries inhabited by these 

 animals is one of the most familiar forest sounds. The calls com- 

 mence at daybreak, and are continued till 9 or 10 A.M., several of 

 the flock joining in the cry, like hounds giving tongue. After 9 or 

 10 o'clock in the morning the animals feed or rest, and remain 

 silent throughout the middle of the day, but recommence calling 

 towards evening, though to a less extent than in the earlier part of 

 the day." 



The skull of the Gibbons, although agreeing with that of other 

 Apes in its prognathism, presents a somewhat human appearance, 

 and the molar teeth are also very like diminutive human molars. 

 In the anterior inward inclination of the two series of cheek-teeth 

 and the inward ri . 



position of the 

 upper premolars 

 the Gibbons make 

 an approach to the 

 human type un- 

 known in other 

 Apes. 



The figure of 

 the liver of one 

 species of this 

 genus is introduced 

 to shoAv the general 

 absence of lateral 

 fissures and the 

 small size of the caudate lobe (c) characteristic of the liver of all the 

 ^imiidce, except Gwillti (see p. 706), as well as that of Man. Another 

 specimen of the liver of the same species showed scarcely any trace 

 of a caudate lobe. 



A fossil Ape from the Middle Miocene of France, originally 

 described as Piiopithecus, indicates an extinct Gibbon which does 

 not appear to be generically separable from Hylobates. 



Simla. 1 Skull (Fig. 353) produced at the vertex ; body and 

 limbs massive ; the pectoral limbs reaching to the ankle ; a centrale 

 in the carpus ; hallux very small ; sixteen dorso-lumbar vertebra?, and 

 twelve pairs of ribs ; no ischiatic callosities. Oriental. 



This genus includes the large red-haired Apes from Sumatra 

 and Borneo commonly known as Orangs, or Orang-Utans, 2 of which 

 there is probably only a single species (S. satyrus). These animals 

 1 Linn. Syst. Nat. 12th cd. vol. i. p. 34 (1766). 

 - A Malay word, signifying " Man of the Woods." 



FIG. 862. Under suilaec of tin- liver of llylolates lar. v, Umbili- 

 cal fissure ; p, jxjrtal ttssure ; vc, vena cava ; I, left lobe ; r, right 

 lobe ; , Spigelian lobe ; c, caudate lobe ; g, gall-bladder. 



