Keywords: Handbook to the Primates Plate 38.jpg Plate XXXVIII Siamang Gibbon Hylobates syndactylus 1897 Handbook to the Primates Vol II http //archive org/details/handbooktoprimat02forb Henry Ogg Forbes 1851-1932 Species Plates by John Gerrard Keulemans 1842 “1912 PD-old-auto-1923 1912 Handbook to the Primates Symphalangus syndactylus |