828 THE ZOOLOGIS'. 
singular is all that can here be taken. The Potto or Bush-dog 
(Perodictcius) is one of the stumpy West African slow-moving 
species. A short tail and well-nigh obsolete fore finger are its 
chief exterior characteristics. Its habits are so similar to 
the better known Asiatic Slow Loris (Nycticebus) that reference 
to the latter will serve both. Seen in the daytime, or made 
to walk on a flat surface, from its weird-looking eyes, sack-like 
body, long limbs, and slow straggling gait, one would predicate 
it the worst of night-hunters; but give it a grasping surface 
and place a beetle before it at night, and the eye lights up 
like a globe of fire: the quiet demeanour and sudden rush 
on the prey is astonishing. The perfect silence in movement, 
tenacity of grasp in climbing, tactile appreciation and dilatable 
eye, all enable the creature stealthily to approach birds, insects, 
and creeping things, and to snatch at and secure them in a 
twinkling. The great-eared Javan T'arsius and the African 
Galagos, on the other hand, are perfect imps of nimbleness. 
Their furling ear-conch catches every sound, their sensitive palms 
and facial vibrissee warn them of every obstacle in their path, 
and the unusually lengthened heel-bones, like frogs, enable them 
to spring astonishing distances, so that they are on their prey 
like lightning. 
The great-eared Aye-Aye of Madagascar, so lucidly described 
by Professor Owen, is even more curiously adapted for its 
peculiar nocturnal rambles. It seems almost blinded by daylight, 
but brilliantly orbed in darkness. ‘The two middle fore-fingers 
are bat-like in tenuity and length, and probe nook, crevice and 
corner with super-sensitive tact and skill. Its whiskers and skin 
warn by delicacy of touch, and its strange rodent-like teeth 
serve as effective chisels in night hunts for creatures, the presence 
of which ear and finger alone indicate. 
The Lemuroids, as a whole, then, embody perfection in varied 
apparatus useful nocturnally. As with the Bats, Mr. Herbert 
Spencer's principle jis highly applicable, viz., “ There can be no 
doubt that the sensation of touch and pressure are consequent on 
accelerated changes of matter produced by mechanical disturbance 
of the mingled fluids and solids composing the part affected.” 
The Douroucouli (Nyctipithecus), a small animal allied to the 
Capuchin and Squirrel Monkeys of South America, decidedly 
leads 2 nocturnal life. Several species have from time to time 
