292 The Senses of the Lower Animals. [July, 
within the range of our own species, if we compare the 
visual powers of man with those of other animals, much 
wider differences must be expe&ed. Nor is this mere 
matter of conjecture. Diredt observation proves that 
numerous species are able to seek their food or their prey, 
meet with their mates, distinguish friends from enemies, 
and find the way to and from their dens or nests in what to 
man appears complete darkness, and where he can scarcely 
move without running into danger. With what skill does 
the owl, hovering over the harvest-field, discern the grey 
mouse upon a soil from which it differs little in colour even 
by day ? Other birds, on the contrary, such as the Gallinacese, 
if disturbed in the night, seem perfectly stupefied, and are 
utterly unable to find a way of escape from danger. 
As regards the range of vision, from what a height and 
to what a distance do eagles, hawks, and other diurnal birds 
of prey espy a suitable vidtim ! On the other hand, if the 
sight of small animals is to be of much use to them, it 
must enable them to distinguish objedts which to our 
unaided vision are simply imperceptible. Concerning dis- 
crimination between different colours, the evidence that it 
is possessed by the lower animals though indirect is con- 
clusive. Were it otherwise the dodtrine of “ sexual selec- 
tion,” instead of being as it is, a hypothesis, not indeed 
demonstrated, but still conceivable, would be a simple 
absurdity. It is still, however, doubtful why sexual selec- 
tion, if it has been a vera causa in the production of colour, 
should have led to brilliant hues in one group of birds or 
insedts, whilst it has permitted the existence of sombre 
shades in another class closely allied and similar in habits. 
Have we here to do with a difference in the perceptive 
organ similar to colour-blindness, or with a difference in 
some inward faculty ? The well-known case recorded by 
John Hunter where a female zebra rejected the advances of 
a male ass till he was painted so as to resemble a zebra is 
in itself quite conclusive. According to Sir S. Baker, the 
African elephant and rhinoceros show an especial enmity to 
white and grey horses, and attack them with remarkable 
fury. Here also belongs the antipathy of the bull and the 
turkey-cock to red-coloured objects. The recognition of 
throws no light, since fossils, as a rule, betray not the slightest indication of 
the hues they may have worn when living. We know that a preponderant 
proportion of the fossil insedts found at Schambelen belong to the gorgeous 
family of the Buprestidce, but even that family includes so many plainly 
coloured groups that no certain conclusion can hence be drawn. A parallel 
question of course arises as regards the frudtification of flowers by the agency 
of insedts in the primeval world. 
