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Show 552 SIR V. BROOKE ON THE GENUS GAZELLA. [June 3, in Greece. The characters I allude to, however, are just such as upon evolutional principles we should expect to find in this old form, and tend to show that the Miocene Gazelle, though highly specialized, was less so than its existing representatives. Gaudry informs us that not only are the limbs of this species thicker than those of Gazella dorcas, which species the Miocene Gazelle very closely resembled, but also that in one specimen, at the back of the metatarsal cannonbone, immediately below the tarsal joint, he discovered a small bone which he thinks represented a rudimentary metatarsal. Now in no existing Gazelle have I as yet been able to discover the smallest trace of the external digits in either extremity, with the exception of the epidermal so-called false hoofs. With regard to the supplementary columns so distinctly shown in Gazella brevicornis in the true molars of the lower jaw, it is not a little singular to find an existing species showing, but only occasionally, traces of these extra columns, whereas Gazella deperdita oi Gervais, a later extinct form than Gazella brevicornis, is entirely devoid of them, though in other respects it appears to have closely resembled that species. The last fact I shall mention with respect to the distribution of the Miocene and Pliocene Antelopes is the great fact that he who runs may read, namely that the scene has completely changed, the old platform over which the extinct forms were distributed being, as far as Europe is concerned, entirely deserted. Now, upon turning to look at the principal features presented by the distribution of the existing Gazelles, the first thing that strikes the attention is the fact that the area in which the group now occurs most plentifully, both in numbers and species, lies immediately to the south of that which was occupied by its Miocene and Pliocene representatives. Out of the nineteen species above described, thirteen are African, twelve of these being confined to North Africa. The six non- African species extend in an eastward direction from Africa into India and Central Asia. With regard to differentiation the most striking peculiarity is the existence of so many forms presenting apparently trivial, but at the same time fairly constant characters of distinction. In the accompanying genealogical table (Plate XLV.) I have endeavoured to express in one view the more important characteristics of the distribution and differentiation of Gazella. In the arrangement of this table I have been influenced principally by the geographical distribution of the species ; and the two right-hand branches may be taken as approximately illustrating the relative position of the species supported by them with respect to their geographical distribution. The species supported in the lower part of the left-hand branch stand to each other relatively in their correct geographical positions. As regards the three species supported upon the upper arm of the left-hand branch, I am far from satisfied, and their positions must be regarded as very doubtful. Now a comparison of this table with the analytical list above given shows the following very suggestive fact-viz. that if lines be drawn from the different circles, connecting only those which represent the species contained in the minor divisions of the analytical list, continuous streams of distribution of similar forms will be found flowing from |