16 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
to be a fair inference that their origin was substantially 
‘the same, and therefore that they at one time possessed 
functional wings, even if they subsequently lost them alto- 
gether. It is an interesting fact that the gigantic extinct 
Aipyornis of Madagascar, which presented many resem- 
blances to the Dinornithide, possessed a distinct, though 
rudimentary, humerus. The combined coraco-scapula of 
this bird is typically Ratite, the angle between the two 
bones being very slight, and there is a distinct glenoid 
cavity. The sternum also was truly Ratite, the most 
striking peculiarity about it being its great shortness as 
compared with its width. 
With this brief survey I must take leave of the Ratites, 
and with them, of my first division of flightless birds. 
Though possessing only functionless wings, and, there- 
fore, in that sense showing inferiority, they cannot be 
looked upon exactly as degenerate birds. They have been 
compensated in great measure for their loss of flight by 
their swiftness of foot, and have thus, as it were, competed 
with the mammals on their own ground, and have held, 
and still hold, their own over wide areas—as in the case 
of the African Ostrich—in the presence of numerous and 
powerful enemies, and they have survived by virtue of 
their capacity to cope with these. ‘That all these birds 
were descended from an ancestor which possessed the 
power of flight, I have given reasons for believing, but it 
is not to be supposed that that ancestor is to be found in 
any of the types of flying birds of the present day. The 
differentiation between the existing Ratites and Carinates 
is too great for that. Rather is the ancestor to be looked 
for in an ancient flying type, from which the Ratite and 
Carinate birds have alike diverged. That this ancestor 
was a true bird, possessing feathers and the power of 
flight, is all that I contend for, 
