556

48

Cnemiornis, although also with a "ratite" or uncarinate sternum, must stand beside
Cereopsis in the Anserine group of Anatidae.

The Didines are but generic modifications of a great natural division of Rasores, the
existing members of which, of smaller size, retain their faculty of flight.

Dinornis shows the consequence of disuse of wings in a greater degree than does
Apteryx. But although the winged forms from which the Kiwi, the Cassowary, the
Emu, the Rhea, the Ostrich and the AEpyornis have severally degenerated remain to
be determined, the wingless kinds each have structural characteristics encouraging the
quest, and testifying against the artificial group (Megistanes, Vieillot ; Proceri, Illiger ;
Ratitae, Merrem : Struthionidae, Vigors) based upon modifications of the breast-bone
and scapular arch, the consequences of disuse and degeneration of the muscles of flight,
and with which a loose character of plumage is more or less associated.

The results of the researches which have determined the real affinities of extinct birds
and keelless breast-bones and long-angled scapulo-coracoids, devoid of acromial and
clavicular processes, support a reasonable expectation that the existing wingless genera,
which have been shown to differ from one another considerably in important anatomical
structure, in correlation with their distinct and remote habitats, will be ultimately
referred to as many distinct natural groups which are now, or which formerly have
been, represented by volant and typical members of the feathered class.

EXPLANATION OF THE PLATES.

PLATE IV.

Fig. 1. Reduced side view of the skull of the male Solitaire.
Fig. 2. Reduced side view of the skeleton of the female Solitaire.
Fig. 3. Copy of a figure of the living Solitaire, from the frontispiece to Leguat's work,
above cited.

PLATE V.

Fig. 1. Side view of the skull of the male Solitaire.
Fig. 2. Top view of the skull of the same.
Fig. 3. Occipital surface of the skull of the same.
Fig. 4. Top view of the skull of the female Solitiare.
Fig. 5. Under view of the skull of the same.

All the figures are of the natural size.