Peters’s Duiker was described in 1876 by the great zoologist after whom we have fashioned its English name, from a single specimen obtained by the late Professor Dr. Reinhold Buchholz during his sojourn in Western Africa, and transmitted to the Berlin Museum. In his notes upon this species Peters informs us that the specimen described, which is an adult female, was brought to Buchholz alive in Gaboon on the 18th August, 1874, and lived two days in captivity. Buchholz stated that the name of this Antelope in the Mpongwe dialect was “_Mbindi_” and noted that the iris was brown, the muffle blackish, and that the animal was provided with large purse-like inguinal glands, like other species of the genus. Peters has given a good coloured figure of the specimen in the ‘Monatsbericht’ of the Royal Prussian Academy of Sciences, in which his memoir on Buchholz’s mammals is published, and likewise an excellent figure of its skull of the natural size. We are not aware that any other museum has been fortunate enough to obtain specimens of this rare Antelope. _May, 1895._ 29. THE RED-FLANKED DUIKER. CEPHALOPHUS RUFILATUS, GRAY. [PLATE XIX. FIG. 1.] _Le Grimm_, =F. Cuv.= H. N. Mamm. (fol.) ii. livr. xxvii. (♂) (1821). _Antilope grimmia_, =Desm.= N. Dict. d’H. N. (2) ii. p. 191 (1816) (_nec_ Pall.); =id.= Mamm. ii. p. 464 (1822); =Less.= Man. Mamm. p. 379 (1827); =H. Sm.= Cuv. An. K. iv. p. 266, v. p. 347 (1827); =Fisch.= Syn. Mamm. p. 468 (1829); =Less.= Hist. Nat. Mamm. (Compl. Buff.) x. p. 294 (1836); =Gerv.= Dict. Sci. Nat. Suppl. i. p. 262 (1840); =Less.= N. Tabl. R. A., Mamm. p. 178 (1842); =Wagn.= Schr. Säug. Suppl. iv. p. 451 (1844); =Schinz=, Syn. Mamm. ii. p. 418 (1845); =Gieb.= Säug. p. 321 (1859). _Cephalophus grimmia_, =A. Sm.= S. Afr. Quart. J. ii. p. 216 (1834). _Antilope (Grimmia) grimmia_, =Laurill.= Dict. Univ. d’H. N. i. p. 623 (1839). _Sylvicapra grimmia_, =Sund.= Pecora, K. Vet.-Ak. Hand-l. 1844, p. 190 (1846); =id.= Hornschuch’s Transl., Arch. Skand. Beitr. ii. p. 142; =id.= Reprint, p. 66 (1848).