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origin by these common characteristics.
1. Both produce a large egg, found no-
where else except monotremes on Duckbills,
a three corned link between birds, reptiles
and mamals.
2. In neither is there a complete diaphragm
below the heart.
3. In each there is but one ball and socket
joint where the head turns on the neck, where
as the mamals and amphibians have two.
4. In each the lower jaw is connected to the
skullsch by an intervening (quadrate) bone not found
in mamals.
5. Neither birds nor reptiles pass through a
tadpole starte, as do the amphibians, or have
special glands (mammae) to nourish their
young, as do the mamals.

Though birds are hot blooded and reptiles cold
blod, birds have feathers and be[...] have scales,
never the less scientists are generally agreed that
both should be placed in the same class. Whether
all birds have sprung from an individual ancestor
is a question on which all are not agreed.

Many think that before birds wore feathers
they flew by skin appendages and even before
this they crawled about in trees walking up
right and clinging to the branches by their hooked