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Show 1905.] OF THE GENUS RHINOLOPHUS. 119 trying to answer this question, the following facts must be borne in mind :-Firstly, that all palaeontological evidence is wanting, which detracts from what we know about the affinities and distribution of the now existing representatives of these Bats. Secondly, that the ferrum-equinum type is unknown in Egypt, as well as in the whole region of the continent north of British East Africa, and that we have no reason, of any kind, to believe that it ever existed there. Thirdly, that we have to account not only for the distribution of Rh. augur and deckeni as compared with the other members of the same section of the genus, but also for the presence in Tropical Africa of representatives of the borneensis and rouxi types, and, be it noticed, representatives which, without exception, are more highly differentiated than their Oriental allies. These facts, so far as they go, seem to allow of no other satisfactory explanation than this: the immigration of these Bats, as of so many other Oriental types in the Ethiopian fauna, has taken place by way of the broad tract of land which, as commonly supposed, in a geologically late period connected Southern Asia with the African continent. In the case of the ferrum-equinum type this explanation would make it evident, why it, though vastly distributed in South and Equatorial Africa, is absent from the whole north of the continent with the exception of the extreme north-western (Mediterranean) coast-region, which it, no doubt, has reached from South-western Europe, since the Algerian race is subspecifically indistinguishable from the Spanish form (Rh. f . obscurus). In the case of the borneensis and rouxi types it would account for the fact that they are common to the Oriental and Ethiopian Begions, but absent from the whole of the Pal pear c tic Begion. And it would also account for the presence of the genus Rhinolophus in the Ethiopian Begion, for, as I shall have to show later 011 in this paper, all the Ethiopian representatives of the genus are undoubtedly of Oriental origin. Such being the case, I am able to draw up the following rough sketch of the history of Rh. augur, deckeni, and their Oriental and Palsearctic relatives :- The ferrum-equinum type has originated somewhere in South Asia; we find there the long series of more primitive forms which lead up to that type, whereas in the whole of the Ethiopian Begion there is not any species with which it can be brought in genetic connection. The ancestral " ferrum-equinum " broke up into three branches : a south-western, a western, and an eastern. The south-western branch, which had spread directly from South Asia into the Ethiopian Region, was cut off from the main stem by the submergence of the connecting tract of land, and is now differentiated into two species-the southern Rh. augur and the northern Rh. deckeni. Both of them have retained at least two " ancient" characters: a slightly more primitive dentition (the upper canine and p4 often more or less separated ; p2 sometimes half in row *) and a short tail. To the external difference * 35 skulls of Uli.augur (all races) have been examined:- In 17 the upper canine and p4 are more or less separated, in 7 in contact, in 11 more or less overlapping |