_b^4._ Rump particoloured. _a^5._ Belly usually lighter than back; female horned.--Cameroons; Zanzibar 33. _C. melanorheus._ _b^5._ Belly not or little lighter than back; female hornless.--Uganda 34. _C. æquatorialis._ _b^3._ Legs rufous; rump not particoloured.--S.E. Africa. 35. _C. monticola._ B. Horns, when present, slanting upwards at a sharp angle above the nasal profile; females normally hornless. Ears long, pointed, their length equal to or exceeding the distance from the eye to the rhinarium. General colour yellow or greyish; no darker markings on the body, but a brown nasal patch present. (TRUE DUIKERS.) _a._ Size smaller: hind foot less than 9 in.; basal length of skull less than 5·5. _a^1._ Colour bright yellow.--W. Africa 36. _C. coronatus._ _b^1._ Colour grizzled greyish brown.--Abyssinia 37. _C. abyssinicus._ _b._ Size larger: hind foot more than 9·5 in.; basal length of skull more than 6·0.--Southern Africa 38. _C. grimmi_[11]. [Illustration: THE BOOK OF ANTELOPES, PL. XIII. _J. G. Keulemans del._ _J. Smit lith._ _Hanhart imp._ The Yellow-backed Duiker. CEPHALOPHUS SYLVICULTRIX. _Published by R. H. Porter._] [Illustration: THE BOOK OF ANTELOPES, PL. XIV. _Smit lith._ _Hanhart imp._ Fig. 1. The Black Duiker. CEPHALOPHUS NIGER. Fig. 2. The Yellow-backed Duiker. CEPHALOPHUS SYLVICULTRIX. _Published by R. H. Porter._] 19. THE YELLOW-BACKED DUIKER. CEPHALOPHUS SYLVICULTRIX (AFZ.). [PLATES XIII. AND XIV. FIG. 2.] _Antilope silvicultrix_, =Afzelius=, N. Act. Ups. vii. p. 265, pi. viii. (animal) (1815) (Sierra Leone); =Goldf.= Schreb. Säug. v. p. 1238 (1818); =Desm.= Mamm. ii. p. 462 (1822); =Less.= Man. Mamm. p. 378 (1827); =Fisch.= Syn. Mamm. p. 457 (1829); =Waterh.= Cat. Mamm. Mus. Z. S. (2) p. 41 (1838). _Antilope (Cephalophus) sylvicultrix_, =Ham. Sm.= Griff. Cuv. An. K. iv. p. 258, plate (♂), v. p. 344 (1827); =Less.= H. N. Mamm. (Compl. Buff, x.) p. 293 (1836); =Gerv.= Dict. Sci. Nat. Supp. i. p. 262 (1840); =Less.= N. Tabl. R. A., Mamm. p. 178 (1842); =Wagn.= Schr. Säug. Supp. iv. p. 446 (1844), v. p. 422 (1855); =Gieb.= Säug. p. 322 (1859).