14 ON THE SYSTEMATIC POSITION OF HESPERORNIS. 
The ribs are in Hesperornis 
As in Colymbus, much flatter and broader than in the Ratites. 
The uncinate processes are, as in Colymbus, large, long, and six in number ; 
in the Ratites they are either small, rudimentary, or absent, and 
never exceed three. 
In the shoulder-girdle of Hesperornis 
The sternum shows distinct traces of having once possessed a keel. It is 
oblong and elongated in form as in Colymbus, not short and shield- 
shaped as in the Ratites. It bears, as in Colymbus, two deep notches 
on its posterior margin. 
The coracoid bears a blunt, square “‘epicoracoid” process as in Colymbus, 
not possessed by the Ratites. 
The coracoid and scapula are separate, not anchylosed as in the Ratites. 
The clavicles meet in the middle line; they do not meet in any Ratite. 
In the pelvic-girdle of Hesperornis 
The ilium is, as in Colymbus, immensely elongated posteriorly to the 
acetabulum, and its pre-acetabular part is very short and small as in 
Colymbus, not long, high, and massive as in the Ratites. 
‘In the hind-limb of Hesperornis 
The femur is short, flattened, and thick as in Colymbus, not long and 
cylindrical as in the Ratites. 
The patella is very long, trihedral, and pointed, as in Podiceps and as in 
Colymbus, except that in the latter it is anchylosed with the tibia: 
but it is small or absent altogether in the Ratites. 
To sum up, it appears to me that from purely osteological characters, the wide 
difference between Hesperornis and any Ratite, and its close resemblance to Colym- 
bus or to Podiceps is clear and patent. From these characters it is a Colymbine 
bird, of great size and prodigious swimming power, which, while losing its wings 
and sternal keel and otherwise somewhat modifying its shoulder-girdle as the faculty 
of flight degenerated, has retained in its brain-case, its palate, its mandibles, its 
vertebree, its sternum, pelvis, and hind-limbs, resemblances almost amounting to 
identity with the existing Colymbi: resemblances as great as between Strigops and 
the other parrots, and much greater than between Didus and the ordinary pigeons. 
There remain the two marked peculiarities of the teeth and the under-sized 
brain. As regards the former, when birds undoubtedly descend from toothed ances- 
tors of some kind, and when every other great division, of the vertebrates comprises 
toothed as well as toothless forms, I cannot see that this fact, however interesting, 
should be permitted to alter or to determine the great lines of ornithological 
classification. 
