48 Mr. F. E. Beddard on the 
uot by any means minute, of this groove for the reception 
of a coiled trachea. I am disposed, therefore, to conclude 
that Balearica is derived from a Crane that had a coiled 
trachea and a corresponding deep excavation of the front 
end of the sternum. Now it is a point of some little im- 
portance, in estimating the systematic position of AramuSy to 
compare the conditions to be seen in this particular region 
of the bird with those observable in the Cranes. A glance 
at the figure already referred to (fig. 3, p. 47) will shew 
that in Aramus the front end of tiie sternum is excavated in 
the same way ; but the excavation is much shallower, though 
even more extensive, than in Balearica. Furthermore, at 
the anterior end of the excavation, just below the rudi- 
mentary spina externa, is a deep hole (shown as a black circle 
in the figures) which has its precise counterpart in Balearica, 
though in the latter bird the hole in question is larger and 
deeper. It cannot, I think, be doubted that we have in this 
Crane-like bird a vestige of a former condition, in which the 
sternum was grooved and excavated in front for the reception 
of the tracheal coil. Here, again, I do not lay any special 
stress uj)on the likeness which Aramus bears in these pecu- 
liarities of structure to Balearica. It is readily credible that 
the tracheal coiling and the corresponding sternal excavation 
may have been independently lost a dozen times ; but in 
any case both birds have progressed along similar lines. 
Nor can I find any evidence that other Crane-like birds 
have recently lost their tracheal coils and are therefore to be 
looked upon so far as equally nearly allied forms of Gruine 
birds. In Psophia, Cariama, Rhinochetus, and Houbara the 
front end of the sternum — the region which is under 
discussion — is, it is true, flattened, but it is not in the least 
hollowed ; and if it were to be suggested that flattening 
is simply a further, and uot a large, exaggeration of the 
slight hollowing to be found in Aramus, it might be replied 
that in the birds mentioned the middle line of the region of the 
sternum, with which we are at present concerned, is traversed 
by a quite distinct ridge, which runs up to, and indeed ujj, 
the spina externa. All these facts combine, in my opinion, 
