This Antelope, the second member of the genus lately discovered and recognized by Mr. Richard Crawshay, seems to be a small highland form of the Poku, and it is possible that intermediate specimens between the two may be hereafter found. In this case _C. senganus_ will have to be reduced to a subspecies of _C. vardoni_. But until such intermediate forms are obtained we do not feel justified in presuming their existence, and therefore class _C. senganus_ as a different species. The only specimen of _C. senganus_ as yet procured is unfortunately a female, young enough still to retain its milk-dentition. The general development of the skull, however, and the fact that, as we are informed by Mr. Crawshay, there was a nearly mature fœtus within the womb, show that the animal had practically attained its full growth, and therefore that its small size may be justifiably used as a distinguishing character. We subjoin the notes with which Mr. Crawshay has favoured us on this species:-- “The form of _Cobus_ represented by the present specimen from Senga, to the west of Lake Nyasa, is only met with, I believe, in the neighbourhood of the Upper Zambesi River, in the water-basins of Lakes Mweru and Tanganyika, and perhaps also in those of one or two more of the Central African lakes. It does not occur in the water-basin of Lake Nyasa itself, where only the large grey _C. ellipsiprymnus_ is found; nor until now has it ever been recorded nearer Lake Nyasa than the valley of the Sayisi River, 30 miles or so east of the southern end of Lake Tanganyika, where _C. vardoni_ is met with. It remains to be seen what naturalists make of it: whether it is to be regarded as only a diminutive race of _C. vardoni_ or as a new species altogether. “In general shape and colouring, seen by itself, it appears to be _C. vardoni_; in size, however, it is considerably smaller; and when specimens of the two come to be laid side by side there may be other points of difference. But I wish to lay stress on the fact that, apart from the _distance_ separating the districts where the two are found, the _physical aspects_ of their several haunts differ very materially. “_Cobus vardoni_ is always found in or on the outskirts of swamps, usually on open, marshy plains, where the grass is rich and green; moreover, as a rule, it is met with in large scattered herds, feeding in the open all over the place--such at any rate has been my experience in the countries bordering on Lakes Tanganyika and Mweru. On the other hand, _C. senganus_ is a native of dry, hilly country, often rough and stony, and far from any swampy land, though near a river. Again, it is not at all plentiful in Senga; I saw only two during my travels in the neighbourhood, both females, of which the present specimen is one. “Regarding the habits of this animal I know very little--no more, in fact, than when, where, and how I became possessed of the specimen, which was as follows:--