118 MR. K, ANDERSEN ON BATS [May 16, 
the African coast of the Gulf of Aden. Jé is the closest existing 
relative of the Himalayan Rh. affinis: the same shape of the 
skull; the same shape of the sella, of the connecting process, of 
the ears; the same structure of the wings (also the same lengthening 
of III.*); the same proportionate length of the tail. But it is 
more advanced in dentition : p, is not only external (as in affinis), 
but very often lost; p*, which in affinis is still in the tooth-row, 
is in clivosws external and very small. In short: Rh. clivosus is 
a“ Rh. affinis” with ferrwm-equinum dentition. 
The clivosus type has found its way very far into the Ethio- 
pian Region. kh. darlingi*, from Mazoe to Angola, is a 
modification of this type (as proved by the skull), differing from 
clivosus in the more pronouncedly pandurate sella, the much 
broader horse-shoe, the much smaller ears, and, by far the most 
interesting, i the shortening of the third metacarpal. This 
last peculiarity is the same as that pointed out above, under 
th. ferrum equinum: in the wing-structure Rh. darlingi differs 
from “h. clivosus quite in the same way as Lh. ferrwm-equinum 
from Kh. afinis. It is a suggestive fact to find this peculiarity so 
exactly copied by the South-African species. 
Kh. acrotist, from Egypt and Erythrea, is, externally, very 
similar to Ph. clivosus; also the wing-structure is the same. But 
the tendency, in elivosus, towards an obliteration of p, and p* has 
been further developed by acrotis: it has completely lost both of 
these teeth, thus being, in this particular respect, the highest 
member of the whole group. h. acrotis is a “ Rh. affinis” with 
a dentition still more advanced than in ferrwin-equinwm regulus. 
(3) Hthiopian species of the ferrum-equinum type.—Rh. augur £ 
is widely distributed, in several geographical races, over the 
southern part of the Ethiopian Region: the Orange River tract, 
Natal, the Lower Zambesi. Jt is the closest existing relative of 
Eh. ferrum-equinum ; the skull, the nose-leaves, the wing-structure 
are the same; but the dentition is a trifle less advanced, and the 
ears are smaller. 
We find the ferrwm-equinum type also further northwards in 
Tropical Africa (Mombasa): Rh. deckent; the skull and dentition, 
and all external characters of any importance, are as in augur; 
but the horse-shoe is broader. 
The area occupied by these two Ethiopian representatives of 
the ferrum-equinum type extends, broadly speaking, from the 
Orange River to Mombasa. It is completely cut off from any 
other region inhabited by that type of Bat; it forms a large 
enclave bordered to the north and west by vast tracts where no 
representative of ferrwm-equinum occurs; we must go so far 
away from South and Equatorial Africa as the Euphrates Valley, 
Syria, and Algeria before meeting with the closest relatives of 
those Ethiopian species. Thus the question suggests itself, by 
which way the ferrwm-equinum type reached Tropical Africa, 
and why its range there is now so peculiarly insulate. When 
* Andersen, Ann. & Mag. Nat. Hist. (7) xv. (1905) p. 70. ~ 
+ Andersen, op. cit. (7) xiv. (1904) p. 454; (7) xv. (1905) p. 73. 
{£ Andersen, op. cit. (7) xiv. (1904) p. 380. 
