Chap. L] BATS. 19 
It has been suggested, that the insectivorous bats, 
though nocturnal, are deficient in that keen vision cha- 
racteristic of animals which take their prey by night. 
EHINOLOPHUS. 
I doubt whether this conjecture be well founded ; it 
certainly does not apply to the Pteropus and the other 
frugivorous species, in which the faculty of sight is sin- 
gularly clear. As regards the others, it is possible that 
in their peculiar ceconomy some additional power may 
be required to act in concert with that of vision, as in in- 
sects, touch is superadded, in its most sensitive develop- 
ment, to that of sight. It is probable that the nose- 
leaf, which forms an extended screen stretched behind 
the nostrils in some of the bats, may be intended by 
nature to facilitate the collection and conduction of 
odours, just as the vast expansion of the shell of the ear 
in the same family is designed to assist in the collection 
of sounds — and thus to supplement their vision when 
in pursuit of prey in the dusk by the superior sensi- 
tiveness of the organs of hearing and smell. 
One tiny little bat, not much larger than the humble 
C 2 
