PROFESSOR OWEN ON THE GENUS DINORNIS. 131 
lamella in Apteryx probably indicates the true condition of the vomer in Dinornis. In 
Dromaius the non-united halves of the vomer diverge posteriorly in a greater degree than 
in Apteryx or Dinornis, exposing a greater proportion of the rostrum. The obliquely 
and mesially concave palatal plates converge anteriorly, not so much or so soon in 
Dinornis as in Apterya, but more quickly than in Dromaius, defining more completely a 
smaller pair of bony palato-nares. It is most probable that the detached representa- 
tives of “palatines” worked out of the matrix, in the first specimen, were the parts 
broken away from the anchylosed union of those bones with the palatal plates of the 
maxillary anteriorly, and with the pterygoids behind. 
In Struthio, Rhea, and Casuarius the pterygoid coalesces with the palatine earlier 
than it does in Dromaius. A greater proportion of the vomer is cleft posteriorly in 
Dromaius than in Rhea. Upon the whole Dromaius, among the larger existing Stru- 
thionidw, makes the nearest approach in palatal structure to Dinornis and Apteryz. 
This closer affinity is shown in the form of the basioccipito-sphenoidal tract and its 
relation to the pterapophyses. In Rhea, which, after Dromaius, comes next in palatal 
conformity, the tract in question sinks abruptly below the level of the pterapophyses, 
which seem to diverge at almost a right angle from the base itself of the rostrum. 
In Dromaius the pterapophyses diverge from the fore part of the tract itself, which 
is on the same level with the back part of the tract, and, as in Dinornis, only distin- 
guished therefrom by the lateral constrictions or grooves due to the pressure of the 
Eustachian tubes. 
The appreciation of the near affinities, among Struthionide, of Dromaius to Dinornis 
and Apteryx led me to select the skull of the Emu to illustrate that of the Moa in my 
first attempts to restore that complex and instructive part of the skeleton of the huge 
extinct New-Zealand apterous birds’. 
The results of the above exposition of palatal structure in the skulls of Dinornis 
crassus have enabled me to restore, from cranial fragments in the Walter-Mantellian 
series, not only the pterygoids and portions of the palatines of Dinornis crassus, but 
also those of the Dinornis ingens as figured in Pl. XV. fig. 3. 
In Dinornis crassus the malar process of the maxillary (Pl. XI. fig. 1, 21), the malar 
(ib. 26), and squamosal (ib. 27) have coalesced into a styliform zygoma 2 inches 2 lines in 
length. The malar rises as a low, obtuse ridge toward the postfrontal ; the squamosal 
has a rough elliptic surface at the inner side of its hinder end, which projects inward to 
an obtuse point effecting the “ gomphosis” with the tympanic (28). This bone (Pl. XI. 
figs. 5 & 6), in relation to the shorter mandible, is relatively as well as absolutely 
smaller than in Dinornis elephantopus; the orbital process (/) is more triangular, has 
a broader base than in Dinornis elephantopus: this process is more produced, with 
* Most of the notable modifications of the palate and pterygo-palatine arches have since been figured by Eyton 
in the rich storehouse of the bony structures of birds, entitled ‘ Osteologia Avium,’ 4to, London, 1864-67, 
VOL. VII.—PaRT U1. Jan, 1870. T 
