The Black-headed Duiker was first described by Dr. Jentink, the Director of the Leyden Museum, in 1885, from a single female specimen procured near Schieffelinsville, on the Junk River, by Stampfli in the preceding year. Unfortunately Dr. Jentink referred the specimen to _C. longiceps_ of Gray, a species based on a skull brought home from Gaboon by Mr. DuChaillu. In doing this he was perfectly justified, on account of the extraordinarily close resemblance of its skull to that of _C. longiceps_. But Thomas subsequently showed that DuChaillu’s Gaboon skull (as already mentioned above) is undoubtedly referable to the nearly allied _C. sylvicultrix_. Under these circumstances it became necessary to give another scientific name to the present species, and Thomas selected the appropriate term _jentinki_; as it was Dr. Jentink’s “carefulness, led astray by Dr. Gray’s serious mistakes,” that had “caused him to make the venial error just referred to.” During his second expedition, in 1887, Mr. Stampfli procured two more examples of this Antelope on the Farmington River. Like the first, both these were females, and, as we are told by Dr. Jentink, do not differ in colour from the typical specimen. Mr. Stampfli’s notes on this Antelope are as follows:-- “A little below Schieffelinsville, in the triangle between the Junk River on one side and its two confluents, the Du Queah and Farmington Rivers, on the other, a wooded eminence called ‘Sharp Hill’ rises in the middle of the marshes, to which, according to the testimony of the natives, these animals are restricted. As in the dry season the marshes cannot be traversed in canoes, and yet are not sufficiently dry to be passed on foot, these Antelopes can only be obtained in the rainy season, and it is said to be quite an exception for a specimen to be procured except during that period.” In the second volume of Mr. Büttikofer’s ‘Reisebilder aus Liberia,’ which contains a complete account of the explorations and discoveries of himself and his companions in that country, will be found some additional details on this Antelope. Mr. Büttikofer calls particular attention to the large size of the inguinal glands between the belly and the thigh in this Antelope. They are so large that they will easily contain a lemon. These are said to be fat-glands, from which the beast extracts fat with its muzzle to lubricate its short, shining, hairy coat. Mr. Büttikofer also says that this Antelope, although only obtained from Sharp Hill, certainly occurs in other parts of Liberia. Our figure of this Bush-Duiker (Plate XV.) has been prepared by Mr. Smit from the mounted specimen in the British Museum, which is the type of the species. It is one of the three specimens obtained in Liberia by Mr. Stampfli, the other two remaining at Leyden. We believe that these are the only three specimens of this rare Antelope existing in any European museum. _May, 1895._ 21. ABBOTT’S DUIKER.