In the breast-bone of the Dodo we plainly discern the Columbine modification of the Gallinaceous type, simplified in the minor development of those parts relating adaptively to the power of flight, and expanded and excavated for the support of the larger gizzard with its heavier grindstones[34]. In comparing the pelvis of _Didunculus_ and _Goura_ (Pl. XII. fig. 5) with that of _Didus_ (Pl. VII. fig. 1), the correspondences are:—in the general shape, proportions and disposition of the ilia; in the articulation therewith of the last pair of moveable ribs, and of the short straight confluent pleurapophyses of the three succeeding sacral vertebræ; then follow, as in _Didus_, three vertebræ without pleurapophyses, these reappearing in the next two with their extremities converging to abut against a prominence of the inner surface of the ilium in the same relative position. The difference here is in the two equal and more slender rib-buttresses, in place of the single stronger one, which is the more common structure in _Didus_; but in _Goura_ I have noted an instance in which it agreed with the _Didunculus_ on the left side, and with _Didus_ on the right, in the last-specified character. In the Crown-pigeons, also, there is an indication of the transverse ridge marking off the under part of the centrum of the first sacral from the rest, and those that follow are less expanded than in the Dodlets; moreover in _Didunculus_ they show a median canal instead of a ridge, while the ridge is feebly indicated here and there and there is no canal in _Goura_. In neither _Didunculus_ nor _Goura_ do the sacral centrums behind the last rib-abutments diminish in breadth so suddenly as in _Didus_: in both the winged Pigeons the hinder part of the pelvic cavity is relatively deeper and narrower than in _Didus_; in both, also, the upper and anterior concave tracks of the ilia are deeper; and in _Didunculus_ the mesial borders do not attain the neural crest, but leave a pair of open longitudinal canals at that part of the pelvis; in _Goura_ those margins reach the neural crest, but do not overtop it at any part. In _Goura_ the acetabula are more in advance of a median position than in _Didunculus_, _Columba magnifica_, or _Didus_. Although the ischiadic foramina are completed by terminal confluence of the ilium and ischium in _Dromaius_ and _Casuarius_, yet the length of those foramina (which are unclosed) in _Struthio_ and _Apteryx_, concomitant with the greater relative length of the pelvis, shows the difference of _Didus_ from the cursorial Brevipennates in this part of the skeleton. The ischia of the winged Pigeons resemble those of the Dodo; but the inner longitudinal ridge is more strongly marked in _Didunculus_: in the _Goura_ it is less developed than in _Didus_; the bone is longer also in proportion to its breadth, and the ischiadic foramen is longer and narrower: the proportions of that in _Didunculus_ are more like those in _Didus_.