RATITZ, AND CARINAT&, 689 
3. Division CARINAT&. Flying birds with a keeled breast-bone 
Apart from the extinct types of Carinate, such as /chthyornds (with 
teeth and biconcave vertebree), and the large Tertiary Odontopleryx, 
with tooth-like pegs of bone on its jaws, there seem to be over 11,000 
living species, These may be grouped in twenty-one orders, such as 
Passeres (thrushes, etc.), Accipitres (hawks, etc.), Columbze (doves), 
Gallinee (pheasants, etc.), Gavize (gulls, etc.), Psittaci (parrots). Of 
the twenty-one orders only three are unrepresented in Britain. 
The old classification of birds into snatchers, perchers, climbers, 
scratchers, stilt-walkers, and swimmers was interesting and suggestive, 
but an arrangement of this sort is bound to be misleading, since birds 
of very different structure may have very similar habits. 
It may be of interest to contrast the two divisions of living birds. 
SOME CONTRASTS BETWEEN MODERN RATITA AND 
MODERN CARINATA 
RATITA, 
CARINATA, 
Running Birds, with wings more 
or less degenerate and unused in 
flight, witha keelless raft-like breast- 
bone. 
The skull is dromzognathous, 
z.e. the vomer is interposed between 
the palatines, the pterygoids, and 
the basisphenoidal rostrum. 
The sutures in the skull remain 
for a long time distinct. The 
quadrate articulates with the skull 
by a single head. 
The long axes of the adjacent 
portions of the scapula and coracoid 
lie almost in the same line, or form 
a very obtuse angle, and the two 
bones are fused. 
The clavicles are small or absent. 
The ilium and ischium are not 
united behind, except in old Rheas 
and Emus, No pygostyle. 
The feathers of the adult have 
free barbs, the Larbules have no 
hooks. There is no oil gland, 
except in the kiwi. There are no 
regularly arranged pterylz. 
The male has a penis. 
The young are always przeccces, 
Vlying Birds, with wings almost 
always well exercised in flight, with 
a keeled breast-bone, 
(The keel is rudimentary in the 
New Zealand parrot Strinmgops, in 
the exterminated Dodo (Dédus), 
and in the extinct Ag/ornis—one of 
the rails. The penguins do not fly 
at all; the Tinamou, the Hoatzin, 
and some other birds, fly very little ) 
Except in the Tinamous, the 
skull is never dromzeognathous, 
z.e. the vomer is not fused with 
the neighbouring bones of the 
palate, and the palatines articulate 
with the basisphenoidal rostrum. 
The sutures in the skull almost 
always disappear very early. The 
quadrate articulates by a double 
head. 
The scapula and coracoid meet 
almost at right angles, and are 
connected with one another by 
ligament only. 
The clavicles are in most cases 
very well developed. 
The ilium and ischium unite, 
enclosing a sciatic foramen. Usually 
a pygostyle, , 
‘The barbs of the. feathers are 
generally united, the barbules have 
hooks. There is usually an oil 
gland. 
The male has rarely a penis. 
The young may be precoces or 
altrices. 
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