The humerus of the Goura closely repeats most of the characters described in that of the Dodo; but its length is proportionally greater, being 3 inches 9 lines, nearly equal to that of the sternum or pelvis, whereas the humerus of the Dodo is little more than half the length of either sternum or pelvis. The processes for the attachment of the muscles are, nevertheless, fully as strongly developed in _Didus_ (Pl. VIII. figs. 12 & 14) as in the volant Doves (Pl. XII. figs. 8 & 9, _Goura_); that, indeed, which is a ridge (_r_) on the back part of the shaft in _Didus_, is a mere rough surface in _Goura_, and does not show in _Didunculus_. The pneumatic fossa, which varies in depth in the two humeri of the Dodo, is in both relatively larger and shallower than in _Goura_. The pectoral process is thinner, but relatively rather more produced, in _Didunculus_. The humerus in _Œdicnemus_, _Otis_, and _Charadrius_ has a more longitudinally extended, thinner, and more produced pectoral ridge than in _Didus_ and the _Columbidæ_; there is a more marked ectocondyloid tuberosity, which in _Charadrius_ becomes a pointed process. There is nothing to be gained by giving the details of the more striking differences which the humerus presents in Penguins, Auks, and birds of prey, as compared with that bone in the Dodo; but a few words may be recorded of the comparison of the humerus of the Dodo with that of the flightless bird of New Zealand so nearly approaching to it in size, which bird is described in the 5th volume of the ‘Transactions’ of the Society under the name of _Cnemiornis_ (p. 395, pl. 66. figs. 7–10). In that extinct species, although the humerus is 5½ inches in length, the parts indicative of the forces by which it was worked are comparatively feebly developed. The ulnar tuberosity is narrower, thicker, more obtuse, and its base has neither the upper nor lower excavation; it rises above the articular head, which is less prominent and narrower than in _Didus_; the pectoral ridge is shorter and situated lower down upon the shaft, not on the same level with the radial tuberosity as it is in _Didus_; the distal articulation is of the same size as in _Didus_, but neither the radial nor the ulnar convexity is so prominent or well-defined. The ulna of the Dodo is shorter absolutely, and much more so proportionally, than in the Goura and most other volant Doves. In these it exceeds the humerus by about one-fourth its own length; in _Didunculus_ (Pl. III.) it is a little longer than the humerus; in the Dodo (ib.) it is shorter than the humerus. The length of the ulna in _Goura coronata_ is 4 inches 6 lines; it is more bent than in the Dodo; the quill-tubercles, seven or eight in number, are more prominent; nevertheless the rough depression for the insertion of the chief flexor is less deep and less defined. The plumed winglet of the Dodo would seem, therefore, to have been frequently and forcibly moved.