INTRODUCTION 0g 
must have been morphologically inferior to these descendants, which on 
evolutionary principles have gone on improving, while the Ratite branch 
retrograded. That this last branch also may have improved and under- 
gone specialization is true, but not to the point, for it can hardly have 
improved up to the level at which was the parting of the ways, and thus 
we are quite justified in continuing to regard the Ratitx as the lower 
branch, and in beginning with them. They were shewn beyond doubt 
by Huxley to form five separate groups, which we shall here, as before,} 
dignify by the name of Orders, adding to them a sixth, though little has 
as yet been made known of its characteristics. Of this, which contains 
the great extinct Birds of Madagascar, he did not take cognizance, as it is 
here necessary to do. In the absence of any certain means of arranging 
all these orders according to their affinities, it will be best to place their 
names alphabetically thus— 
JEPYORNITHES. Fam. Apyornithide (Roc). 
APpTERYGES. Fam. Apterygidz (Kiw1). 
Immanes. Probably two Families 2—Dvinornithide (Moa). 
Meretstanes. Fam. i. Caswariide (Cassowary); Fam. ii. Dromexide 
(Emev).? 
Rue® Fam. Rheide (RuEa). 
SrrRuTHIONES. Fam. Struthionidx (OsTRICH). 
Some systematists think there can be little question of the Struthiones 
being the most specialized and therefore probably the highest type of 
these Orders. Nevertheless the formation of the bill in the Apteryges is 
quite unique in the whole Class, and indicates therefore an extraordinary 
amount of specialization. Their functionless wings, however, point to 
their being a degraded form, though in this matter they are not much 
worse than the Megistanes,t and are far above the Immanes—some of 
which at least appear to have been absolutely wingless, and were thus the 
only members of the Class possessing but a single pair of limbs. 
Turning then to the Carinate, their subdivision into Orders is attended 
with a considerable amount of difficulty ; and still greater difficulty is 
presented if we make any attempt to arrange these Orders so as in some 
way or other to shew their respective relations—in other words, their 
genealogy. In regard to the first of these tasks, a few groups can no 
doubt be at once separated without fear of going wrong. For instance, 
the Crypturt or Tinamous, the Impennes or Penguins, the Striges or Owls, 
the Psittact or Parrots, and the Passeres, or at least the Oscines, seem to 
stand as groups each quite by itself, and, since none of them contains any 
1 See Ann. Nat. Hist. ser. 4, xx. pp. 499, 500. It must, however, be borne in 
mind that what here is meant by an “Order” of Aves is a very different thing from 
an “Order” of Reptilia. 
2 On this see Prof. T. Jeffery Parker’s most instructive paper (Trans. Zool. Soc. 
xiii. pp. 373-431, pls. lvi.-]xii.), in which, though admitting only a single Family, be 
recognizes three Subfamilies—Dinornithine, Anomalopterygine and Hmeine. 
3 Since this was in type Dr. Stirling has announced (Zrans. Roy. Soc. S. Austral. 
xx. pp. 171-190) that fossil remains of a gigantic bird, Genyornis, found at Calla- 
bonna in South Australia, prove it to have been allied to the Emeus, in which case 
a third Family of Megistanes will probably be required. 
4 Nor, possibly, than the dpyornithes (cf. Andrews, [bis, 1896, pp. 376-389, pls. 
viii. ix.). 
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