136 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
For our present purpose, this question as to the homogeneous or 
compound character of the Ratite is of prime importance, involving as 
it does the problem of common or multiple origin for its several mem- 
bers, and hence the key note of their distribution. If we admit, for 
instance, as has been suggested by some, that the South American 
ostrich was derived from the tinamous or some other Carinate stock, 
then it must be altogether excluded from the list of forms that migrated 
into the western hemisphere by means of a former land connection. 
But if, on the other hand, structural resemblances are sufficient to point 
to a genetic relationship with the ostrich or other Struthious type, 
then its occurrence in Patagonia can be accounted for in no other way 
than on the hypothesis of a land migration. 
Or again, in the case of the remarkable Stereornithes, from the early 
Tertiary of Argentina and Patagonia, which were considered by Ame- 
ghino, Gadow, and for a time also by Lyddeker, as ancestral forms of 
Ratite, — if they could be shown really to have Struthious affinities it 
would be a simple matter to connect them and the modern Whea with 
Diatryma from the Eocene of New Mexico ; further, with the Tertiary an- 
cestors of Struthiolithus, Struthio proper, and the moas of New Zealand ; 
and perhaps finally with the little known Gastornithide from the London 
and French Eocene. Indeed, much stress was laid by Lyddeker on the 
resemblances between Gastornis and the leading genus of the Stereor- 
nithes, Phororachos. But however attractive such a theory might seem 
at first glance, we are obliged to renounce it as illusory in view of recent 
destructive criticisms at the hands of such excellent anatomists as F. A, 
Lucas, C. W. Andrews, and others, who have caused even Ameghino 
and Lyddeker to recede from their original opinions. 
The last named author,! writing in 1893, placed Gastornis, Brontornis, 
and Phororhachos unhesitatingly among the Zatit@, as the latter are 
commonly understood. He refers to “the modern German [Fürbring- 
ers] view that the Ratite form a compound group, of which the 
various sections have been independently derived from several perfectly 
distinct Carinate ancestors, and that their mutual resemblances to one 
another are solely owing to the effects of adaptation” ; but his own 
personal opinion is expressed in the following words: “I confess, 
however, that the supposed Anserine affinities of Gastornis appear far 
from clear to me, while I always feel that the great difficulty in admitting 
the multiple origin of the Ratite is that, if this had been the case, there 
1 Lyddeker, R., On the Extinct Birds of Argentina (Ibis, [6], Vol. V. pp. 46, 47). 
1893: 
