94 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
direction would have been quickly cut off and wiped out of 
existence. 
But the conditions of life were altogether too easy for 
it ; a superabundance of food, to be had for the picking of 
it up, and an absence of any enemies to interfere with it, 
produced their usual result, and degeneration set in—a 
result, | may remark, by no means confined to the Dodo, 
but one of which, under similar circumstances, proud Man 
himself furnishes conspicuous examples. As long as the 
conditions of life remained uniform, the Dodo throve 
luxuriantly, but with the advent of man upon the scene, 
the balance was upset, and the helpless, defenceless con- 
dition of the birds rendered them an easy prey, whilst the 
hogs and cats turned loose in the island by its early 
discoverers completed the work of destruction. 
The extermination of the bird appears to have been 
complete by the end of the 17th century, less than 100 
years from the earliest notice of it by the first Dutch ~ 
occupiers of the island. 
The sternum of the Dodo is very interesting, for it 
shows that the keel—that special characteristic of flying 
birds—has become greatly reduced in depth, measuring, 
in fact, not more than # inch in a sternum about 7 inches 
in length. The keel is, however, there, a plain record of 
a time when the wings were functional, and required a 
keel for the attachment of the muscles which moved them. 
The scapula and coracoid were ankylosed together at a 
wide angle, in this respect resembling the condition found 
in the Ratite. 
Turning now to a bird of a very different character, 
Notornis mantelli from New Zealand, presents us with 
the very interesting case of a bird first described from 
fossil specimens undoubtedly contemporaneous with the 
Moa, and supposed to be extinct, but of which living 
