202 MR. W. P. PYCRAFT ON THE MORPHOLOGY AND 
sphenoid, anchylosis therewith taking place later. ‘Thus it is that the pro-dtic comes to 
be entirely concealed. 
Jn all this, Dromeus and Casuarius seem to be less primitive than the Penguin. Ina 
skull of this group recently described and figured by me [82] the squamosal was attached 
to the dried skull simply by its articulation with the parietal. Its hinder border was 
deeply emarginate and free, exposing the pro-dtic. Its anterior border was also free, 
not extending to the alisphenoid, but exposing between itself and this last a small 
portion also of the pro-dtic. 
There is one great point of difference, however, between the squamosal of Dromeus 
and that of the Penguin. In the former, its antero-ventral angle is produced 
downwards into a large “zygomatic process,” to embrace the quadrate; in the latter, 
this spine is replaced by two small spines, as in all the Neognathe. 
Except in Apteryx the squamosal takes no part in the formation of the inner wall of 
the skull. 
In Apteryx the squamosal has entered into a slightly closer relation with the 
alisphenoid and exoccipital than in the forms described. above, resembling in this 
respect the Veognathe. Thus the anterior border is concave and fits the corresponding 
convex border of the alisphenoid ; whilst the posterior border, though separated by 
a narrow line of cartilage from the exoccipital, yet gives signs of effecting a close union 
therewith immediately. 
The squamosal appears on the inner surface of the skull as a small triangular plate 
above the pro-otic. 
The nasal in Dromeus is holorhinal. The maxillary process is greatly reduced, 
especially so in the adult, where it exists only as a vestige. It is produced caudad into 
a long slender process resting on the frontal, and projecting beyond the lozenge-shaped 
plate of the mesethmoid, to which it binds externally. Its premaxillary or internal 
process is of considerable length, extending forwards almost the whole length of the 
nasal process of the premaxilla, which protects them from above. 
Dinornis is holorhinal. 
A skull of Megalapteryx, in the collection of the Hon. Walter Rothschild, retains 
sufficient of the traces of sutures in this region to indicate the form of the nasal in the 
Dinornithide. 
In this skull, it is seen to be relatively much shorter than in Dromeus. Its backward 
extension does not pass the level of the horizontal mesethmoid plate and is not so 
pointed as in Dromeus. Its maxillary process is wanting. ‘The ossified aliethmoidal 
plate projects beyond its lateral border, 
In Casuarius the nasal is schizorhinal. ‘The maxillary process is vestigial, and the 
premaxillary process long, as in Dromwus. It is peculiar in that the body of the bone 
is greatly inflated and takes part in the formation of the casque as already described 
