have suckled the young. Several friends of the present writer
have seen this done in India and Ceylon by male "wet-nurses." As there
is no tribe of men or species of ape in which the male suckles the young
normally, we seem to be thrown back once more upon an earlier ancestor.
The difficulty is that we know of no mammal of which both parents
suckle the young, and some authorities think that the breasts have been
transferred to the male by a kind of embryonic muddle. That is difficult
to believe, as no other feature has ever been similarly transferred to
the opposite sex. In any case the male breasts are vestigial organs.
Another peculiarity of the mammary system is that sometimes three, four,
or five pairs of breasts appear in a woman (and several have been known
even in a man). This is, apparently, an occasional reminiscence of an
early mammal ancestor which had large litters of young and several pairs
of breasts.

But there are features of the human body which recall an ancestor even
earlier than the quadruped. The most conspicuous of these is the little
fleshy pad at the inner corner of each eye. It is a common feature in
mammals, and is always useless. When, however, we look lower down in the
animal scale we find that fishes and reptiles (and birds) have a third
eyelid, which is drawn across the eye from this corner. There is little
room to doubt that the little fleshy vestige in the mammal's eye is the
shrunken remainder of the lateral eyelid of a remote fish-ancestor.

A similar reminiscence is found in the pineal body, a small and useless
object, about the size and shape of a hazel-nut, in the centre of the
brain. When we examine the reptile we find a third eye in the top of
the head. The skin has closed over it, but the skull is still, in
many cases, perforated as it is for the eyes in front. I have seen it
standing out like a ball on the head of a dead crocodile, and in the
living tuatara--the very primitive New Zealand lizard--it still has a
retina and optic nerve. As the only animal in nature to-day with an eye
in this position (the Pyrosome, a little marine animal of the sea-squirt
family) is not in the line of reptile and mammal ancestry, it is
difficult to locate the third eye definitely. But when we find the skin
closing over it in the amphibian and reptile, then the bone, and then
see it gradually atrophying and being buried under the growing brain, we
must refer it to some early fish-ancestor. This ance