EOUSETTUS JiGYPTIACTJS. 
89 
the tibia, a condition which becomes reversed in adult age. A comparison, however, 
between the length of a compound member, such as the thumb, and a simple 
bone, such as the tibia, could not but be unreliable unless it had previously been ascer¬ 
tained that growth had ceased in all the bones which had formed the subject of 
comparison. 
The same caution is also necessary before deductions can be made regarding the 
relative proportions which the long bones of the limbs hold to one another in adult 
life. In certain mammals the absolute length of the tibia in the early stages of 
development is considerably less than that of the humerus, whereas in adult life the 
latter bone is ultimately shorter than the former. From these facts, and by a reference 
to the foregoing table, it will be seen that Dr. Gunther was justified in questioning the 
validity of the supposed diagnostic character laid down by Dobson. 
There can be no question as to the specific identity of the Cyprus and the two 
Palestine bats with those of North-eastern Africa, 
I his species is closely allied to jR. colldTts^ but when examples from Egypt are 
compared with specimens from South-Africa they are found to have slightly longer 
and broader muzzles and somewhat longer ears. ' These differences, however, are so 
trivial that when extensive materials from the immense area intervening between the 
Cape and Cairo have been brought together and studied, the probability seems to be 
that B. Gollaris will he found to merge with B. cegyptiaciis. Besides its larger size, the 
chief feature of the skull of the latter as compared with the former, when viewed from 
above, is its broader muzzle. The teeth also of B. cegyptiacus are larger than those of 
B. collaris. 
A bat closely allied to B. wgyptiacus occurs in S.E. Arabia, but its size is less, and 
its muzzle is narrower than in B. collaris. The ear is more pointed than that of the 
Egyptian bat, and both its borders are markedly less convex, more especially the inner 
one, which is nearly straight. The ear is also broader than the ear of B. collaris, 
which is markedly oval compared with the ear of B. cegyptiacus and of the bat from 
Arabia. The crania, when viewed from above, present certain features by which it is 
possible to distinguish one from the other when the skulls are considered side by side. 
Thus the skull of B. mgyptiacus has a decidedly broader muzzle than that of B. collaris, 
which in its turn has a wider muzzle than that of the Aden bats. When the under 
surface of the skull is examined, the palatal region is found to conform in its general 
characters with those of the muzzle seen from above. Thus, the palatal area of 
B. oegyptiacus is broad and spatulate, that of B. collaris is less so, while that of the 
Aden bats is distinctly narrowed anteriorly and less expanded posteriorly between the 
last molars. The bats from Aden are greyish brown, slightly darker on the top of the 
head, whilst the area between the shoulders is pale grey with a yellowish tinge, and 
the longest hair on the neck of males is yellowish brown. These Aden bats were 
N 
