207 
upon the parietals (Pl. LI, fig. 1,7) of one inch eight lines in breadth: this tract is 
almost flat: two very shallow channels, four lines broad, diverge from the flat parietal 
surface along the upper part of the skull close to the anterior border of the temporal 
fossze and terminate at the upper part of the much-developed and deflected postfrontal 
(ib, 12). Between these shallow impressions the frontal region is slightly convex, but 
it becomes a little concave at its anterior half, the middle of the fore-part of which is 
impressed by a sharply-defined shallow channel for the reception of the cranial and 
of the median branch of the coalesced premaxillaries. The large tympanic fossa, over- 
arched by the mastoid (id. fig. 2,8), shows the single oblong deep cavity for the upper 
condyle of the tympanic bone, with the pneumatic, jugular, and auditory foramina, and 
the adjacent trigeminal one (ib. tr). An arterial canal is continued upwards from the 
posterior aperture of the carotid canal, and grooves or notches the lower border of the 
paroccipital. The antero-posterior extent of the temporal fossa (7b. fig. 2, 7, tr, 12) is 
one inch eight lines, indicating, with the depth of the same fossa, the great strength 
of the temporal muscles of this bird. The median part of the roof of the orbit is 
slightly convex towards that cavity: the lateral part becomes concave by the remarkable 
downward production of the postfrontal. But, perhaps, the most extraordinary features 
are the olfactory depressions on the under surface of the frontals, the dimensions of 
which have already been given. ‘he great extent of these depressions has been dwelt 
on in previous memoirs as peculiarly characterizing the great wingless birds of New 
Zealand, and it becomes remarkably striking in the present large cranium. The olfactory 
foramen opens into the upper part of the posterior third of these cavities, and the 
grooves which radiate from each foramen indicate the dispersion of the branches of 
the nerve after its emergence from the cranium. One cannot avoid the inference 
that the living bird must have been remarkable for its acuteness of smell. The 
deep circular ‘sella turcica’ has not increased in the same ratio: there is a special 
depression at its back part above that which receives the orifices of the entocarotid 
canals. 
The upper and median branch of the premaxillary (ib. fig. 1, 22") slightly expands at its 
flattened cranial end, but that part is broken away which would have filled the depression 
on the frontal (ib. 22”). Allowing for it according to the proportions of the cranium with 
the entire lower jaw restored at Pl. XLV., the length of this skull would be about 
eight inches. But the skull is much shorter in proportion to its breadth than in the exist- 
ing large Struthious birds, or than in the Palapteryx described and figured in Pl. XLY. 
As the median branch of the premaxillary advances forwards, it decreases in breadth 
and increases in thickness; its outer margins become rounded, and it sends down 
from the median line of its inferior surface a ridge (ib. fig. 2, n), which divides the external 
nostrils anteriorly, and which rapidly expanding, as it descends, becomes continued into 
the broad palatal plate of the premaxillary. The back part of the base of the septum 
presents a triangular depression, on each side of the base of which is a canal, which 
aK 2 
