194 BIRDS

in some of the penguins it is as long as the tibia; at
the lower end of B is the ankle, which is really on its
upper portion, the tibio-tarsus ; and then comes D,
representing all that is left of the tarsal bones. The
toes are more readily distinguishable. The ‘hallux,’
or great toe, is the one at the back, that marked e is
the ‘inner’ toe, representing the second digit in man,’
counting from between the legs outwards; the long one
is the middle toe, the other the ‘outer’ toe. The
fifth toe is missing in birds ; when there are but three
toes it is the hallux which has gone; when there are
but two toes, as with the ostrich, it is the second and
third that remain. Normally, a bird has fourteen toe
joints, two being in the hind toe, three in the inner
toe, four in the middle toe, and five in the outer toe ;
but these vary, and their variations are of some use in
classification. It may perhaps assist us to point out
that B is the ‘drumstick ;’ and in our diagram of the
breastbone we showed, at the top, in position, the
‘merry thought, or furculum, formed of the united
clavicles, next to them coming the coracoids, the
coracoids and scapule forming the so-called side-
bones.

CARINAT4.—These are generally said to be
the flying birds, but the statement must not be taken
too literally, for the order includes the penguins, and
such exceptional forms as the burrowing New Zealand
parrot, the dodo, and the aptornis, besides the tina-
mous and the hoatzin, which can hardly be called
flyers. There are two main divisions at the least,
first those with teeth, the Odontornithes, and second