138 
PROFESSOR OWEN 
CH. V. 
utmost amount of light which may pervade the 
forests at sunset, dawn, or moonlight. Thus the 
aye-aye is able to guide itself among the branches 
in quest of its hidden food. To discern this, 
however, another sense had need to be developed 
to great perfection. The large ears are directed 
to catch and concentrate, and the large acoustic 
nerve and other structures of the organ seem 
designed to appreciate any feeble vibration that 
might reach the tympanum from the recess in the 
hard timber, through which the wood-boring larva 
may be tunnelling its way, by repeated scoopings 
and scrapings of its hard mandible. How safe 
might seem such a grub in its teak or ebony-cased 
burrow ! Here, however, is a quadrumanous 
quadruped in which the front teeth, by their great 
size, strong shape, chisel structure, deep implanta- 
tion and provision for perpetual renovation of 
substance, are especially fitted to enable their 
possessor to gnaw down with gouge -like scoops to 
the very spot where the ear indicates the grub to 
be at work. The instincts of the insect, however, 
warn it to withdraw from the part of the burrow 
that may be thus exposed. Had the aye-ayo 
possessed no other instrument — were no other 
part of its frame specially modified to meet this 
exigency it must have proceeded to apply the 
incisive scoops in order to lay bare the whole of 
the larval tunnel, to the extent at least which 
would leave no further room for the retracted grub’s 
