36 THE BOOK OF A NATURALIST 
this animal is our relation, but even such a creature 
as the bat! 
Look on this picture, and on this! On the eyes, 
for instance, of these two beasts, and we see at 
once that the bat is an example of extreme degenera- 
tion; also that it is the most striking example in 
the animal world of a degenerate in which the 
downward process has at length been arrested, and 
instead of extinction a new, different, and probably 
infinitely longer life given to it. 
We are reminded of the flea—the remote de- 
scendant, as we deem, of a gilded fly that was 
once free of the air and feasted at the same sunlit 
flowery table with bright-winged butterflies and 
noble wasps and bees. 
There are those who have doubts about this 
genealogical tree of the bat, and would have it 
that he is an insectivore related to moles, shrews, 
and such-like low-down animals, but the main facts 
all point the other way. And we may assume that 
the bat—our familiar flittermouse, since we are not 
concerned with the somewhat different frugivorous 
bats of the tropics—is the remote descendant of a 
small degenerate lemur that inhabited the upper 
branches of high trees in the African forest; that 
he became exclusively insectivorous and developed 
an extreme activity in capturing his winged prey, 
and was in fact like the existing small lemur, the 
golago, which in pursuing insects “ seems literally 
to fly through the air,” as Sir H. Johnston has 
said. Finally, there was the further development, 
