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CHAPTER III
REPTILES

No one is likely to mistake a living bird for a reptile,
but in the past the distinction would have been any-
thing but easy; and even now the internal resem-
blances are so great that it has been proposed to
class the two together. It has, however, been found
convenient to keep them separate as hitherto, and to
bear their close relationship in mind.

There are five orders of living reptiles—the croco-
diles, the snakes, the lizards, the rhyncocephalians
having only one living representative, the New
Zealand tuatera, and the tortoises.

CROCODILIA.-—The crocodiles have their teeth
in distinct sockets, whereas the other reptiles have
theirs growing to the jawbones. They have a four-
chambered heart, and a diaphragm between the
organs of their chest and.abdomen. They lay eggs
about the size of those of a goose, which have a thin
shell and are buried in a hollow in the ground, so as
to be hatched by the heat of the sun ; and when the
youngsters begin to cry within their shells the mother