Heuglin, in his various memoirs on the Antelopes of N.E. Africa, did not keep G. isabella separate from G. dorcas, and united their localities. Sir Victor Brooke, in his monograph of the Gazelles, though he divides them and says that “amongst the smaller Gazelles no two species could produce two more dissimilar animals than typical specimens of G. dorcas and G. isabella,” states his conviction that “every intermediate degree between them will be found represented in intermediate localities.” It is indeed true that G. isabella is a very inconstant species and requires further careful study.
There can be no doubt that Dr. Blanford’s Gazella dorcas, in his volume on the ‘Geology and Zoology of the Abyssinian Expedition,’ is what we here call G. isabella. The figure of its horns (op. cit. plate i. fig. 1) shows the characteristic twist inwards at the upper end. Moreover, a skull of a male (from Zoulla) and a skull and skin of a female (from Amba), obtained by him during the expedition, and now in the British Museum, are evidently referable here. Mr. W. L. Sclater has also catalogued four heads in the Calcutta Museum, obtained by Mr. Blanford on the same occasion, as G. Isabella. Mr. Blanford gives us the following field-notes on the present species:—
“So far as my observation extends, neither this nor Bennett’s Gazelle are ever seen in large flocks, like the animals of the Springbok group. Usually both are seen solitary or in parties of from two to five together, inhabiting thin bushes, generally on broken ground. They feed much upon the leaves of bushes. The male has a peculiar habit when surprised of standing still and uttering a short sharp cry. Like most Antelopes, they keep much to the neighbourhood of some particular spot. After long observation, I am convinced that Bennett’s Gazelle never drinks, and all that I could ascertain of the present Gazelle leads to the same conclusion in its case.”
In our efforts to obtain further information about the Isabella Gazelle, we did not fail to apply to the officers of the Anglo-Egyptian garrison at Suakin for a set of specimens of it for the National Collection. In reply to our requests Major Sparkes, Surgeon-Capt. Fleming, and Lieut. Carleton were kind enough to send to the British Museum five examples of it; but we cannot say that the examination of these specimens has enabled us altogether to understand this very difficult species. Of the five examples from that locality, three have and two have not a black nasal patch, while the dark lateral band in some is fairly distinct and in others almost obsolete. It is thus evident that these characters, of systematic importance elsewhere, are not, in G. isabella, even of local constancy.
Among the Gazelles registered in the Zoological Society’s ‘List of Animals’ (1896) as received during the past twelve years there have been several which, doubtless, should have been referred to the present species, but have been entered under Gazella dorcas. Amongst these may be specified an example presented by Commander W. Crofton, R.N., in July 1890 (specimen e), a female presented by Col. Holled Smith, C.B., in July 1892 (specimen g), and a pair (h, i) received on deposit in May 1894.
After the arrival of these specimens from Suakin, Mr. A. Thomson, the Head-Keeper, called Sclater’s attention to their differences from the ordinary G. dorcas. They were of a more reddish colour, and had a broad and somewhat distinct side-stripe and a blackish nasal spot, in addition to other smaller differences.
Besides the specimens of this Gazelle in the British Museum which we have already referred to, there is a mounted male from the Anseba River, formerly in Sir Victor Brooke’s collection, and presented to the Museum by Sir Douglas Brooke. We believe that our coloured figure (Plate LXIV.), which was prepared by Mr. Smit under Sir Victor’s superintendence, was taken from this specimen.
May, 1898.
Fig. 69. Fig. 69a.