5j2 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 limhs of this species thicker than those of 

 Oazella dorcas, which species the Miocene Gazelle very closely re- 

 sembled, but also that in one specimen, at the back of the metatarsal 

 cauuonbone, immediately below the tarsal joint, he discovered a small 

 hone 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 supplemen- 

 tary 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 depenlita of Gervais, a later extinct form than 

 Gazella brevicornis, is entirely devoid of them, though in other re- 

 spects 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 repre- 

 sentatives. Out of the niueteen 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 distinc- 

 tion. 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, continu- 

 ous streams of distribution of similar forms will be found flowing from 



