_ 1905. ] OF THE GENUS RHINOLOPHUS. 119 
trying to answer this question, the following facts must be borne 
in mind :—Firstly, that all paleontological 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 ferrwm-equinwm 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 im- 
migration of these Bats, as of so many other Oriental types in the 
Kthiopian 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 con- 
tinent with the exception of the extreme north-western (Medi- 
terranean) coast-region, which it, no doubt, has reached from 
South-western Europe, since the Algerian race is subspecitically 
indistinguishable from the Spanish form (A. f. obscurus). 
In the case of the borneensis and roux types it would account 
for the fact that they are common to the Oriental and Ethiopian 
Regions, but absent from the whole of the Palearctic Region. 
And it would also account for the presence of the genus Rhino- 
lophus in the Ethiopian Region, for, as I shall have to show later 
on in this paper, all the Ethiopian representatives of the genus 
are undoubtedly of Oriental origin. 
Such being the case, | am able to draw up the following 
rough sketch of the history of Rh. augur, deckeni, and their 
Oriental and Palearctic relatives :— 
The ferrum-equinwm 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 
Region there is not any species with which it can be brought in 
genetic connection. The ancestral ‘“ferruwm-equinwm” 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. deckent. Both of them have retained at least two 
“ancient” characters: a slightly more primitive dentition (the 
upper canine and p* often more or less separated; p* sometimes 
half in row*) and a short tail. To the external difference 
* 35 skulls of Rh. augur (all races) have been examined :—In 17 the upper canine 
and pt are more or less separated, in 7 in contact, in 11 more or less overlapping 
