Height at withers 39 inches in an old male. General colour of back rich chestnut rufous, sharply bounded on the upperside of each flank by the very distinct light lateral line, which passes below imperceptibly into fawn-colour, much paler than the dorsal colour, no trace of a dark lateral line being present. The fawn-colour also extends on to the crown, all round the neck, on the shoulders, hips, and down the limbs. Central line of face deep rufous; area round eye whitish, sometimes extended forwards as a light final streak towards the muzzle, but more often stopping just anterior to the openings of the lacrymal glands. Backs of ears pale fawn-colour; area round their bases but little lighter than rest of head. Fawn-colour of throat projecting down on to chest, as in _Ammodorcas clarkei_. Outer sides of limbs pale fawn throughout. Tail about 10 inches in length, rufous-fawn like the body basally above, whitish below, the tip tufted with black; on each side of its base the white of the hams, which is very narrow, runs up as a pointed projection into the dark body-colour. The skull of an old male measures 8·75 inches in basal length, the greatest breadth being 3·8, and the muzzle to orbit 4·7. The horns of good specimens attain 15 or 16 inches in length round the curves, but southern specimens, those from East Africa, have not, as a rule, such fine horns as those from Somaliland. _Female._ Similar to the male, but without horns. _Hab._ Somaliland, and thence southwards to the Tana Valley, and the Kilimanjaro district of British East Africa. This Antelope was first made known to science by the late Sir Victor Brooke in 1878 in the last of the many excellent articles which he published in the Zoological Society’s ‘Proceedings.’ His description was based on two skulls with horns attached to them which were lent to him for examination by Mr. Gerald Waller, F.Z.S., at whose request they were named by Brooke after Mr. Waller’s brother, “who lost his life in Africa.” Although it is not so stated by Brooke (who was presumably ignorant of the fact), Mr. Waller’s specimens of this Antelope are now known to have been given to him by Sir John Kirk, at that time H.B.M. Consul at Zanzibar. In reply to enquiries Sir John kindly informs us that these skulls were procured by hunters in his employment on the coast near the River Juba in Southern Somaliland. Sir John subsequently shot specimens of it himself in the same district (where at that period it was very common), and also brought living examples of it away to Zanzibar.