10 SIMIIDiE. 



is wholly black, with the exception of a white streak over the eyes and the cheeks, 

 which are ashy grey ; but in another example in the Paris Museum, also regarded 

 as a type, the ashy grey of the cheeks is absent, and the supraorbital pale line is 

 reduced to a mere trace. 



In this species, as in S. lar, the index and middle toes of the hind feet are 

 occasionally united by a web. 



Inhabits Sumatra. 



Htlobates (Siamanga) syndactylus, Piafl3.es. 



Simla Gibbon, C. Miller, Phil. Trans, vol. xiv. (abridged ed.) 1778, p. 318. 



Pithecus syndactylus, Desmarest, Mamm. 1820, p. 531; Lesson, Man. de Mamm. 1827, p. 30. 



Uylobates syndactylus, P. Cuv. Hist. Nat. des Mammif. var. 1821, pi. iv. ; Diet, des Sc. Nat. 

 vol. xxxvi. 1825, p. 287; Griffith, An. King. vol. v. (1827) p. 6; Bory de St. Vincent, Diet. 

 Class. d'Hist. Nat. vol. xii. 1827, p. 283; G. Cuv. Reg. An. nouv. ed. vol. i. 1829, p. 90; Is. 

 GeoiF. St.-Hil. Voy. aux Indes Orient. Belanger, 1834, Zool. p. 30 ; Cat. Me'thod. des Mamm. 

 1851, p. 9; G. Bennett, Wanderings in New South Wales, 1834, vol. ii. p. 151; Miiller, 

 Tijdschv. voor Natuur. Gescli. en Phys. vol. ii. 1835, p. 324 ; Schlegel, Essai sur la Phys. des 

 Serpens, Pt. Gen. 1837, p. 236; Waterhouse, Cat. Mus. Zool. Soc. Lond. 1838, p. 4; Wagner, 

 Schreber, Saugeth. Suppl. vol. i. 1840, p. 69, Suppl. vol. v. 1855, p. 15; Lesson, Sp. des 

 Mammif. 1840, p. 50; Is. Geoff. St.-Hil. Arch, du Mas. vol. ii. 1841, p. 535; Comptes 

 Rendns, vol. xv 1842, p. 717; Martin, Hist, of Quadr. (Monkeys) 1841, p. 420 (plate); 

 S. Muller (mid Schlegel) ,Verhandel. over de Zool. 1 839-44, p. 15 ; Sandifort, Mliller und Schlegel, 

 Verhandl. 1839-44, pp. 31, 33, pi. ii. figs. 3-5 (brain) pi. vii. figs. 1-3 (larynx & sac) ; Blyth, 

 Jom-n. As. Soc. Beng. vol. xiii. 1844, pp. 463, 474; vol. xliv. ex. no. 1875, p. 3; Sehinz, Syn. 

 Mamm. vol. i. 1844, p. 28; Gervais, Hist. Nat. des Mammif. 1854, p. 51, figure; Flower, Nat. 

 Hist. Review, 1863, p. 279 (plate); Giebel, Zeitsch. ges. Ntrwiss. 1866, p. 186. 



8imia syndactytus, Raffles, Trans. Linn. Soc. vol. xiii. 1822, p. 241 ; Horsfield, Zool. Res. in Java, 1824, 

 plate; Fischer, Syn. Mamm. 1829, p. 11; Heifer, Journ. As. Soc. Beng. vol. vii. 1838, p. 858. 



Siamanga syndactyla, Gray, Cat. Mamm. B. M. 1843, p. 1 ; Cat. Monkeys and Lemurs, B. M. 1870, 

 p. 9 ; Horsfield, Cat. Mamm. E. Ind. Co. Mus. 1851, p. 1 ; Dahlbom, Stud. Zool. Fam. Reg. 

 An. 1856, p. 71. 



Body more robust than in Uylobates hoolock : pelage deep, woolly, black, with 

 no pale supercilium, nor white around the face. A bare area on the throat corres- 

 ponding to the position of a large dilatable laryngeal sac. The index and middle 

 toes of the foot united to the last phalange. 



Inhabits the Island of Sumatra; the Malayan peninsula (Wallace); Tenasse- 

 rim {Heifer). 



The skull of H. syndactylus is distinguished from the skull of the other Hylo- 

 bates by the greater forward projection of its supraorbital ridges and by its much 

 deeper face. It is also the largest skull of the genus. The occipital region 

 appears to be more abruptly truncated than in the other species, but the brain cavity 

 does not seem to be relatively broader than in the shorter and smaller skulls of 

 H. hoolock and E. lar. The skulls of all Hylobates are more or less depressed, but 

 the truncation of the central portion is more distinctive of E. syndactylus than 

 of the other species. 



