_Published by R. H. Porter._] 24. THE BLACK-FRONTED DUIKER. CEPHALOPHUS NIGRIFRONS, GRAY. [PLATE XVIII. FIG. 1.] _Cephalophus nigrifrons_, =Gray=, P. Z. S. 1871, p. 578, fig. 6 (skull), pl. xlvi. (animal); =id.= Cat. Rum. B. M. p. 27 (1872); =id.= Hand-l. Rum. B. M. p. 96 (1873); =Peters=, MB. Ak. Berl. 1876, p. 482 (Cameroons); =Scl.= List Anim. Z. S. (8) p. 147 (1883); =Thos.= P. Z. S. 1892, p. 419; =Lyd.= Horns and Hoofs, p. 210 (1893). _Cephalophus aureus_, =Gray=, Ann. Mag. N. H. (4) xii. p. 42 (1873) (jr.); =id.= Hand-l. Rum. B. M. p. 95 (1873). VERNACULAR NAME:--_Ngolo_ in the Cameroons (_Buchholz_). Size medium. Colour of body rich chestnut, scarcely or not at all paler below. Centre of face and crest deep black, contrasting markedly with the rufous superciliary streaks. Nape browner. Feet and tip of tail blackish, a few white hairs in the terminal tuft of the latter. Hoofs apparently longer in proportion than usual; lower edge of the posterior outer hoof 1·57 inch in length. Horns, judging only from the cores, decidedly short, and but little expanded at their base; the cores in an adult male about 1·9 inch long. Their set parallel to, and a little below, the level of the nasal profile. Skull with the frontal region decidedly convex. Muzzle rather narrow and elongated. Anteorbital fossæ of medium depth. Median posterior palatine notch some distance (⅓ inch in type) in front of the level of the lateral notches. Dimensions:--♂. Approximate height at withers 19 inches, ear 2·3, hind foot 9·2. Skull: basal length 6·3 inches, greatest breadth 3·1, muzzle to orbit 3·6. _Hab._ Coast of Western Africa from Cameroons to Gaboon. Although the great wood-region of Western Africa has been repeatedly visited by naturalists since the days of Afzelius in the last century, and many collections have been formed there, very little has been recorded respecting the habits of the mammals of this part of the continent. The reason of this, no doubt, is mainly the impenetrable nature of the forests and bush which cover the whole country and which allow much fewer observations to be made upon the habits and peculiarities of the animals than in the more open and easily traversed districts of the Ethiopian Region. Of the present and several other species of this genus of Antelopes, for example, we shall see that very little information can be given except what results from the examination of their skins and skulls brought home as specimens for our museums. [Illustration: Fig. 18. Skull of _Cephalophus nigrifrons_. (P. Z. S. 1871, p. 598.)]