These four legions are again combined into two "Brigades," the first
of which comprises the first and second legions, while the second
brigade contains the third and fourth legions.
Thus the whole classification becomes a rounded-off phylogenetic
system, which, at least in its broad outlines, seems to approach the
natural system, the ideal goal of the scientific ornithologist. The
main branches of the resultant "tree" may be rendered as follows:--
CORACIOMORPHAE
+
ODONTOLCAE..COLYMBO + PELARGO- ALECTOROMORPHAE..RATITAE
MORPHAE MORPHAE
\----+----/ /
\----------+---------/
|
NEORNITHES
The Odontolcae seem to be an early specialized offshoot of the Colymbo
Pelargomorphous brigade, while the Ratitae represent a number of side
branches of early Alectoromorphae. The Ratitae branched off, probably
during the Eocene period, from that still indifferent stock which gave
rise to the Tinami + Galli + Gruiformes, when the members of this
stock were still in possession of those archaic characters which
distinguish Ratitae from Carinatae. It follows that new groups of
Ratitae can no longer be developed since there are no Carinatae living
which still retain so many low characters, e.g. configuration of the
palate, precoracoid, pelvis, intestinal convolutions, copulatory
organ, &c. Loss of the keel is co-ordinated with the power of using
the forelimbs for locomotion; although a "Ratite" character, it is not
sufficient to turn a _Notornis, Cnemiornis_ or _Stringops_, not even a
_Phororhacos_ into a member of the Ratitae.
Another branch of the Alectoromorphae, in particular of the
Galliformes, when these were still scarcely separated from the
Gruiformes, especially rail-like birds, leads through Opisthocomi to
the Cuculiformes. These are, again in an ascending direction,
connected with the Coraciiformes, out of which have arisen the
Passeriformes, and these have blossomed into the Oscines, which, as
the apotheosis of bird life, have conquered the whole inhabitable
world. (H. F. G.)