4 
slight risings : the postfrontals form the depressed lateral angles; the 
anterior border is emarginate and coalesces with the nasals and pre- 
maxillary, without being elevated above them. In Palapteryx the 
frontals are more produced anteriorly before coalescing with the base 
of the beak. In Otis the interorbital part of the frontals is deeply 
and widely excavated. In Didus the frontals are broad and convex, 
rising singularly above the cranial ends of the nasals and premaxil- 
lary, with which they also coalesce. The supraorbital plate presents 
a rough notch near the fore-part, where in Dinornis there is a shal- 
low emargination. In Dinornis there is a shallow depression with 
vascular grooves at the outside of the base of the postfrontal distinct 
from the temporal fossa: in Didus the temporal fossa extends for- 
wards above the postfrontal and forms there a reniform, depression, 
either for a gland, or what is less likely, for a co-extension of the 
origin of the temporal muscle. The postfrontal is a strong trian- 
gular obtuse process, ending freely as in Palapteryx, not joined to 
the mastoid as in Dinornis. ‘The orbitosphenoids, indicated by the 
optic foramina, continue the roof and septum of the orbits by coales- 
cence with the alisphenoids behind, the frontals above, the prefrontals 
in front, and the presphenoid below : they send aridge upwards and 
outwards to the under part of the postfrontals, but do not present 
that singularly swollen character which is so peculiar in Didus; in 
which also the prefrontals form a large smooth protuberance, like a 
tumour, at the fore-part of the orbits, and appear on the upper sur- 
face of the cranium in front of the antorbital process of the true frontal 
and external to the lachrymal. The interorbital bony septum is entire 
in both Dinornis and Didus; but in the latter it is more than an 
inch in thickness and cellular, and in this respect more resembles 
the singular structure of the part in Apteryx. The orbits are smaller 
in Dinornis than in the large existing Struthionide or in Otis, but 
are larger than in Apteryx. The olfactory chambers in Dinornis are 
less developed than in Palapteryx and Apteryz. 
The nasal bones in Dinornis and Otis converge where they over- 
lap the prefrontal (ethmoide, Cuv.) in order to join the frontal and 
include that end of the nasal process of the premaxillary, which is 
on a lower plane; and, as they advance, they pass beneath that 
process, coalesce with it and with each other, and terminate in 
Dinornis ina point. In Didus the nasals also anchylose with the 
frontal, where they are separated by the nasal process of the pre- 
maxillary, as indicated by the two longitudinal fissures, which, com- 
mencing behind at 2 lines distance from the outer border of the 
anchylosed base of the beak, gain that border at 1 inch 9 lines 
distance from the frontal, and thus indicate the proportions of the 
base formed by the anchylosed nasals: the fissure can also be traced 
as in Dinornis, bending inwards upon the under surface of the nasak 
process of premaxillary, to about 3 inches from the frontal, when 
the fissure returns back, inclining to the median line, and meets its 
fellow there. All the outer part of the median stem or base of the 
beak defined by these linear furrows I regard as the nasals, which 
thus support the nasal process of the premaxillary. 
