Amongst the many zoological discoveries made by the great naturalist and traveller Dr. Edward Rüppell in Abyssinia and the surrounding lands about sixty years ago was the present species of Antelope, which he proposed to call “_defassa_” from its Amharic name. Rüppell published a figure and description of it in a work which he called ‘Neue Wirbelthiere zu der Fauna von Abyssinien gehörig,’ and dedicated to the Senate of his native State, the Free City of Frankfort-on-the-Main. After an excellent description of both sexes of _Antilope defassa_, Rüppell tells us that it lives in the grassy valleys of Western Abyssinia, round the Lake of Dembea, where it is generally met with in small families of from four to six individuals. Amongst these there is never more than one wholly adult male. What it prefers for food are the leaves and seed-stalks of _Holcus sorghum_ besides grasses of every sort. Its gait is rather unwieldy, but it is not very timid. This Antelope, Dr. Rüppell continues, is also met with in Sennaar and Kordofan, where its common name is “Bura”; skins from these districts examined by him in Cairo were recognized as being similar to the Abyssinian “_Defassa_.” The Abyssinians do not often hunt this species, because so few of them care to eat meat, and its hide is of little value. It is, however, said to be the habitual food of the lions of the district that it inhabits. Rüppell’s specimens of both sexes are now in the Senckenbergian Museum at Frankfort, where Sclater has examined them. Another great explorer of Eastern Africa, Th. v. Heuglin, met with this Antelope in the bushy and woody valleys of the Qualabat and Mareb, and thence eastwards to where the mountain-range falls off into the lowlands. He found it generally less difficult to approach than other Antelopes, and had many opportunities of shooting it at morning and evening amongst the high grasses that border the woods. [Illustration: Fig. 32. Head and foot of “Nsumma Antelope” (_Speke_). (P. Z. S. 1864, p. 102.)] Sir Samuel Baker, in his ‘Albert Nyanza,’ alludes to this species as the “Mehedéhet” and gives a figure of the head in the second volume of his work. On arriving at the banks of the River Asua, which flows into the Nile north of the Victoria Nyanza, Baker tells us (_op. cit._ vol. ii. p. 15) that he “observed a herd of these beautiful Antelopes feeding upon the rich but low grass of a sand-bank in the very middle of the river.” He managed to secure one of them, which was found to weigh about 500 lbs., and was sufficient to supply a good dinner to the whole party. To _Cobus defassa_, we now believe, must be referred the “Nsumma” of Uganda and Madi, a head of which was brought home from his celebrated journey by Speke, and was doubtfully referred by Sclater, in his account of Speke’s Mammals, to the Sing-sing. This head is still in the British Museum, and on comparison of it with a stuffed specimen of the present species shows few points of difference.