PROFESSOR OWEN ON THE GENUS DINORNIS. 183 
of that plate upward, and to turn the horizontal under surface, 20, into a vertical 
outer surface of the bone, which rapidly gains in depth, and has its upper part bent 
inward, to complete with the vomer, 13, the hind wall of the palato-narial canal. At 
the outer and back part of the canal the palatine is thickened at its lower part to arti- 
culate with the pterygoid, 24. 
The yomer is bifid, as in D. ingens and as in the first-described skull of D. crassus 
(tom. cit. pl. xi. fig. 3, 13). The parial plates of the vomer overlap the sides of the 
presphenoids, 9, of which the anterior apex, 9'. coalesced with the narial septum, 
projects beyond the vomer, and partially divides the prepalatine vacuity. ‘The anterior 
ends of the halves are overlapped by the vomerine processes of the premaxillaries. 
Each half of the vomer consists of a deep vertical bony plate, almost meeting below the 
presphenoidal rostrum, expanding at both ends anteriorly to join the premaxillary 
and the palato-maxillary plates, and there bounding the palato-nares anteriorly; pos- 
teriorly expanding in a greater degree, and curving outward and forward to join the 
palatines, and form the posterior boundaries of the palato-nares. These apertures are 
each 1 inch 7 lines in length, 53 lines in breadth ; the breadth across both apertures is 
1 inch 114 lines, the additional half line giving the interval between the halves of the 
vomer. 
The suture between the vomer and palatine, as one looks down upon the skull’s base, 
runs along the bottom of the vomero-palatine or postnarial fossa, along a shallow 
channel there ; it seems obliterated near the postero-external rather thickened border 
of that fossa. From this border the pterygoid process of the palatine is divided by a 
triangular shallow depression. The pterygoid is short, three-sided, with the sharp 
angle between the inner and outer facets of the under surface of the bone turned down- 
ward, and continuing backward a similar ridge on the under part of the palatine. 
The pterygoid has an extent of articulation with the tympanic of more than half an 
inch in D. maximus. 
In this, as in smaller species of Dinornis, well-ossified sesamoid bones added to the 
leverage of the muscles of the foot by their interposition at the back part of both the 
proximal and distal joints of the metatarsal segment. The tibio-tarsal sesamoid 
(Plate XXXL. figs. 3-6) works upon the shallow rounded surface at the back part of 
the ectocondylar fossa of the metatarsus. It is an elongate, trihedral, conical bone, with a 
slight sigmoid flexure. The end representing the base (fig. 3) is external or looks fibulad ; 
the opposite or inner end, or apex, is obtuse. The base is triangular, almost flat, with 
rough ligamentous marks, The two articular sides are half concave half convex length- 
wise; on the narrower side the convexity is next the base, and the reverse on the 
broader side. The non-articular side is almost flat and has faint linear and irregular 
impressions. In one specimen the ligamentous or tendinous attachments to the base 
were partially ossified. 
Here I propose to conclude the task of restoration of Dinornis mavimus. The liberal 
