The first example of this Antelope to reach Europe was transmitted to the Royal Zoological Museum of Berlin by Werne, a well-known German artist and traveller, from the River Sobat in Sennaar. It was characterized as belonging to a new species by Lichtenstein and Peters in a communication made to the Royal Academy of Sciences of Berlin in 1853, and in the following year was carefully described and figured by the same authors in the ‘Denkschriften’ of the Academy. The type specimen, an adult male, remains mounted in the gallery of the Berlin Museum (where Sclater has examined it), and is, we believe, that from which the original water-colour drawing of Wolf for the accompanying Plate was prepared. The next traveller who appears to have met with the White-eared Kob was Consul Petherick, who brought home a skin, two heads, and several skulls of this species on his return from the Bahr-el-Ghazal in 1859. These specimens, which are in the British Museum, were at first incorrectly referred by Gray, in his article upon Petherick’s Mammals, to _Cobus lechee_, which, however, is quite a distinct species and never ranges nearly so far north. Besides the Berlin and British Museums the only other collection that, so far as we know, contains a perfect example of this rare Antelope is the Royal Museum of Turin. Here, as Count Salvadori kindly informs us, there is a fully adult male example of _Cobus leucotis_ mounted in the gallery, and standing about 35 inches high at the withers. This specimen was originally received alive from the Sudan, along with other animals, by King Victor Emmanuel, and on its death was presented to the Turin Museum. Heuglin, in 1861, included this species in his list of the Antelopes and Buffaloes of North-east Africa, and gave a figure of its head, designating the Rivers Sobat and Bahr-el-Ghazal as its localities. It is probable that Heuglin’s “_Adenota kul_” and “_A. wuil_,” described as new in the same memoir, should also be referred to the present species; but as the descriptions are very meagre and, so far as we know, no specimens of these problematical species are extant, this must remain a matter of some uncertainty.