SIMIIDA 731 
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 
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 show the general Fic. 352.—Under surtace of the liver of Hylobates lar. u, Umbili- 
absence of lateral cal fissure; p, portal fissure; ve, vena cava; 1, left lobe; 7, right 
i lobe; s, Spigelian lobe; ¢, caudate lobe; g, gall-bladder. 
fissures and the 
small size of the caudate lobe (c) characteristic of the liver of all the 
Simiide, except Gorillu (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 Pliopithecus, indicates an extinct Gibbon which does 
not appear to be generically separable from Hylobates. 
Simia1—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 vertebrae, 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,” of which 
there is probably only a single species (S. satyrus). These animals 
1 Linn. Syst. Nat. 12th ed. vol. i. p. 34 (1766). 
2 A Malay word, signifying “ Man of the Woods.” 
