8 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
Carinate birds, we should expect to find the fore-limb 
developed on a different pattern to the wings of flying birds, 
but this, as we shall see, is far from being the case; and 
if a quite definite relationship to a Carinate wing can be 
made out in the Ostrich, we may probably infer the same of 
the other Ratites. The sternum of the Ostrich, as of all 
other birds of this class, differs of course greatly from that 
of the vast majority of Carinate birds in its flat raft-like 
character, with absence of all trace of a keel ; but I submit, 
and this truth will become more apparent later on, that 
the absence of a keel is simply the anatomical expression 
of the loss of flight, and too much importance has been 
attached to it as pointing to an entirely different origin for 
the birds which have it not from those which have it; that 
the keel is not there now does not, to my mind, prove that 
it has never been there. The coracoid is broad, and 1t 
and the scapula are fused together into one bone at a very 
open angle—another character common to all the Ratites 
as distinguished from the Carinates. Struthio also has no 
clavicles, though certain of the Ratites, such as the Hmeu 
and Cassowary, possess rudimentary ones. ‘Turning now © 
to the fore-limb proper, we shall see that this is simply a 
reproduction in almost every character, except that of rela- 
tive size, of the type presented by every Carinate bird of 
the present day. 
Take an illustration of the bones of the right wing of a 
Duck, and side by side with it place a figure of the cor- 
responding manus of the Ostrich, and let me direct your 
special attention to the bones of the pinionormanus. The 
single metacarpal bone consists of three bones fused into 
one (it contains also some elements of the carpus, but 
these are indistinguishable in the adult state), correspond- 
ing with the three digits or fingers of birds; the first bone 
being very short, and indicated merely by a prominence at 
