582 Transactions of the Royal Society of South Africa. 
aspect of either ramus of the mandible is pierced in numerous places by 
these air-holes, and there may occur other small ones on the outer surface. 
The sclerotal platelets of an eyeball are comparatively rather small, 
and they differ from each other but very little in size ; otherwise they do 
not present anything beyond their usual ornithic characters. 
Upon comparing the hyoid arches with the descriptions and figures of 
those given in Mivart's paper, cited above, I find that this skeletal portion 
of the tongue in Palaeornis comes nearer to the corresponding parts of those 
structures in Nanodes discolor than to those of any other species there 
described. Especially is this observable in the short entoglossum in these 
two species ; but then there may be other parrots with the osseous parts of 
the tongue still more like those bones in Palaeornis ; and doubtless there 
are, for Nanodes discolor may not be particularly near our present subject 
in other respects, in so far as I am aware, though it may be. 
The glosso-hyal {entoglossum) is notably short in Palaeornis in the 
antero-posterior direction, while it is composed of two separate pieces, as I 
believe it is in all Psittaci. Either one of these is pointed posteriorly, 
and supports an oblique enlargement distally. They only meet mesially at 
a minute point in the middle line somewhat posterior to their middles. 
The basihyal is anteriorly elongated, and supports, upon either side, the 
peculiar forward-projecting, spiculiform processes seen on this element of 
the skeleton of the hyoid in so many birds of this group. Urohyal, 
which is not very long, is co-ossified with the basihyal. 
The ceratohranchials are long compared with the other elements (hypo- 
bran chials of Mivart), while the epibranchials (ceratobranchials of Mivart) 
are very short and thick, terminating posteriorly in fine, short, hair-like 
cartilaginous terminations. As taken together, the thyrohyals are straightish, 
not especially elongated, and present scarcely any upward curvature. 
I made no careful study of the ossifications of the larynx, the trachea, 
or the other parts of the air-passages ; but they do not seem to present 
any very striking differences, in so far as they are concerned, when 
contrasted with what we find in other ordinary parrots ; but when I say 
this I do not desire to have it understood that it would be a profitless task 
to study and compare these parts, for it would most assuredly be both 
important and interesting, and would have been undertaken here had I had 
the proper material for comparison. 
Of the Axial Skeleton. — Palaeornis docilis agrees with Psittacus erithacus 
and Lorius fiavopalliatus, and doubtless w^ith other parrots, in having 
nineteen free vertebrae between the skull and the pelvis. This number, 
however, is not found in this cervico- dorsal region of the column in all 
Psittaci, for in Commis carolinensis there are eighteen, and but seventeen 
in the representatives of the genus Ara. 
Mivart has so minutely described the several vertebrae in this section of 
