XXVI.--St. John's Macaque _Macacus sancti-johannis._ XXVII.--White-crowned Mangabey _Cercocebus æthiops._ XXVIII.--Green Guenon _Cercopithecus callitrichus._ XXIX.--Boutourlini's Guenon _Cercopithecus boutourlinii._ XXX.--Erxleben's Guenon _Cercopithecus grayi._ XXXI.--De Brazza's Guenon _Cercopithecus brazzæ._ XXXII.--Talapoin _Cercopithecus talapoin._ XXXIII.--Bay Guereza _Colobus ferrugineus._ XXXIV.--White-tailed Guereza _Colobus caudatus._ XXXV.--Hose's Langur _Semnopithecus hosii._ XXXVI.--Everett's Langur _Semnopithecus everetti._ XXXVII.--Proboscis Monkey _Nasalis larvatus._ XXXVIII.--Siamang Gibbon _Hylobates syndactylus._ XXXIX.--Orang-utan _Simia satyrus._ XL.--Gorilla _Gorilla gorilla._ XLI.--Bald Chimpanzee _Anthropopithecus calvus._ XLII.--MAP I. Showing the distribution of Living and Fossil _Lemuroidea_. XLIII.--MAP II. Showing the distribution of the Family _Tarsiidæ_, and of the Sub-family _Galaginæ_ of the _Lemuridæ_. XLIV.--MAP III. Showing the distribution of the Family _Chiromyidæ_, and of the Sub-families _Lemurinæ_ and _Indrisinæ_, and of the Sub-family _Lorisinæ_ of the _Lemuridæ_. XLV.--MAP IV. Showing the distribution of Living and Fossil _Anthropoidea_. XLVI.--MAP V. Showing the distribution of the Families _Hapalidæ_ and _Cebidæ_. XLVII.--MAP VI. Showing the distribution of the Genera _Papio_, _Theropithecus_, _Cynopithecus_, _Cercocebus_, _Cercopithecus_, and _Macasus_. XLVIII.--MAP VII. Showing the distribution of the Genera _Semnopithecus_, _Nasalis_, and _Colobus_. XLIX.--MAP VIII. Showing the distribution of the Genera _Hylobates_, _Simia_, _Gorilla_, and _Anthropopithecus_. {1}ORDER PRIMATES. THE BABOONS, MANGABEYS, AND MACAQUES (_Continued_). THE MACAQUES. GENUS MACACUS. _Macacus_, Lacép., Mem. de l'Inst., iii., p. 450 (1801).