348 MR. W. P. PYCRAFT ON THE MORPHOLOGY 
palatines meet one another in the middle line caudad, and 
support the vomer between them, whilst the pterygoids join the 
palatines not by suture, but by a true joint. 
The Schizognathous skull of any adult Gull or Plover will 
admirably illustrate the differences between the Paleo- and 
Neognathez. The changed form and relations of the palatines 
are here almost diagrammatically emphasized. Anteriorly, they 
are seen to be quite independent of the maxillo-palatine processes, 
passing below them, and forwards, to fuse with the palatine 
processes of the premaxille. Behind, they touch one another 
and join the long pterygoids by a joint. On both ventral and 
dorsal aspects strong keels have been developed. The inner 
ventral keels have grown downwards so as to enclose the vomer 
in a deep, cavern-like hollow. The vomer itself is seen to be 
held in position by the embrace of the mesial dorsal border of 
the palatines. In size it is now relatively greatly reduced, but 
has developed a strong blade-like keel * passing backwards into 
a pair of rami attached to the dorsal border of the palatines as 
we have just indicated. The maxillo-palatine processes are not 
unlike those of the Tinamous, being shell-like scrolls of bone. 
They do not, however, extend so far backwards, afford support 
to the palatines, nor embrace the vomer. The pterygoids are 
long, rod-shaped, and articulate with the palatines by a true 
joint. Basipterygoid processes for the support of the pterygoids, 
caudad, have been dispensed with. 
The pterygoid, in some Lari, is keeled dorsally ; and this keel 
increases in height from before backwards, so that immediately 
behind the pterygo-palatine articulation it has attained a con- 
siderable height, rising to embrace the parasphenoidal rostrum on 
either side. It is possible that modifications in the form of the 
pterygoid, to be discussed presently, may be traceable to the ex- 
cessive development of this terminal portion of the pterygoid keel. 
The adult skull in the Neognathe, it has just been remarked, 
differs from that of the Paleognathe, amongst other things, in 
that the pterygoid is a free bone, articulating at the one end 
with the quadrate, at the other with the palatine. 
This being so, it follows that the relations between the vomer 
* The yomer in many forms, e. g. Cariama, is represented only by a blade- 
like lamina; in others this is reduced to a mere spicule, ¢.g. some Galli 
whilst in many forms it is entirely wanting. 
