104 
THE MAMMALS OF EGYPT. 
underneath the free anterior margins of this membrane are the minute nostrils, which 
are consequently placed completely on the upper surface of the muzzle. The nose-leaf 
is horseshoe-shaped in the anterior part of the snout, but bejond is prolonged backwards 
as a free erectile leaf-shaped membrane overlying a deep concavity on the frontal region 
of the head. Anteriorly this membrane is traversed longitudinally by a pronounced 
convexity or midrib, resulting from a mesial longitudinal fold, as is seen by its being 
concave posterrorly. Its anterior end is connected to the posterior bolder of the more 
or less cordate second or overlying membrane, which occupies the concavity of the 
horseshoe-shaped portion of the nasal appendage. This cordate-like membrane is 
only attached to the horseshoe membrane immediately before and behind the nostrils, 
but its free border is notched anteriorly, so that each section acts as a valve to protect 
or to close the nasal passages. In Megaderma lyra the anterior border is freer than 
in M. spasma and M. cor, and in the mesial line there is a rounded eminence in 
M. lyra that slightly raises it and tends to bring it in contact with the septum dividing 
the nostrils. Its posterior portion is perfectly free, and the convexities on its outer 
surface are due to the folding of the membrane and are concave behind. The eyes 
are very large, and over the inner canthus of each there is a large wart, and from this 
point a marked fold of skin is attached to the back of the inner half of the erectile 
leaf-like portion of the nasal appendages. These two folds define a deep recess which 
passes forwards behind the nose-leaf as far as the attachment of the horseshoe-shaped 
portion in the mesial line behind the nostrils. These membranes are more or less 
clad with short hairs anteriorly, but less so posteriorly. The foregoing characters are 
distinctive of M. lyra, M. spasma, and M. cor. On the other hand, the anterior border 
of the horseshoe-shaped portion of the nasal appendage, which in the foregoing species 
has only a feeble free margin, is greatly developed in M. frons. It projects upwards 
as a foliaceous expansion, and is so folded in the mesial line as to give rise to a marked 
process overlooking the division between the nostrils. The so-called midrib of the 
erect foliaceous portion of the membrane, which is enormously developed in this 
species, gradually expands anteriorly into the equivalent of the cordate portion in the 
other species, which becomes very obscure in M. frons, and assumes the character of a 
basal expansion of the midrib. The anterior free borders of this portion of the 
equivalent of the cordate membrane are expanded on either side into similar hairless 
expansions lying over the nasal orifices in close contact with the equally hairless 
posterior upturned free border of the horseshoe-shaped membrane. The nostrils are 
thus even more protected than in the other species. The mesial pit behind the 
membranes is not so much developed as in the other species. In M. lyra, M. spasma, 
and M. cor the lower lip has a mesial groove with a fleshy eminence on each side of it; 
the groove does not exist in this species {M. frons), but the front of the lip is 
fleshy. 
