FLIGHTLESS BIRDS. 7 
for progression on land. This includes all the true Ratite 
birds, and hence comprises, amongst existing birds, the 
Ostrich (Struthio), the South American Ostrich (Rhea), 
the Cassowary (Caswarius), and the Emeu (Dromeus) 
from the Australian region, and the little Apterya of New 
Zealand; whilst, amongst extinct birds, must here be 
classed the various species of Moa, included in the family 
Dinornithidz of New Zealand, and the Aupyornithidee of 
Madagascar. It is possible that the Stereornithes, a group 
of gigantic flightless birds, discovered in recent years 
in the Tertiary deposits of Patagonia, should here be 
included. They were originally so classed by their dis- 
coverer, Ameghino, but later researches have thrown 
great doubt upon them being true Ratites. Their affinities 
are not, indeed, sufficiently known to render it profitable 
to discuss them, and I will merely remark that the most 
striking thing about them was the enormous size of the 
skull, which, in one species, measured 2 feet in length; 
they possessed also well-formed wings, but these were 
apparently quite useless for the purpose of flight. Other 
fossil forms also occur, which are less equivocally Ratite, 
such as Gastornis, Dasornis, &c., but these I shall not 
allude to further. 7 : 
To examine in detail the fore-limb girdle in all the 
above birds would, of course, take one far beyond one’s 
limits, and it must suffice to take one or two examples as 
types of the rest. 
The Ostrich (Strwthio) differs from other members of 
the Ratite in certain important particulars, such, for 
instance, as the structure of the skull and the presence of 
only two toes, but the likenesses considerably outweigh 
the differences, and point definitely to a common origin 
for the class. If, therefore, the Ostrich were descended 
from a totally different stock to that which produced the 
