210 BIRDS

cation of birds would be an anatomical one, in which
the skull would be of the first importance. Huxley
classified the Carzzat@ according to the shape of their
vomer, the thin small bone standing upright in the
middle of the mouth ; and this arrangement, as altered
slightly by Parker,has much in its favour. Wis first
division into those with the vomer broad behind and
those with it narrow behind shut off the tinamous,
all the rest of the carinates having vomers narrowing
posteriorly. These he sorted into those with the
maxillo-palatine bones united, which brought into one
group the birds of prey, the parrots, cuckoos, king-
fishers, hoopoes, bee-eaters, ducks, flamingoes, herons,
storks and ibises, and pelicans. The rest of the birds
with the maxillo-palatines free were then divisible
into three groups: those with the vomerine halves
distinct, as the woodpeckers ; those with the vomer
pointed in front, as the plovers, gulls, penguins, auks,
grebes, petrels, game-birds, and humming-birds ; and
those with the vomer truncated in front, as the swifts
and passerines. And these main groups were further
sorted out under types. But we need dwell no further
on this matter, which it was necessary to mention by
way of caution that the old classifications based on
every part indiscriminately—head, tail, beak, claws,
legs, breastbone, wings, and feathers—are:to be
considered as under revision with a view to retire-
ment.

A bird can fly almost as high in the air as a
fish can swim-below the surface of the sea. There
is one bird which has a range in the air of over
three miles in vertical height. This is the condor,