346 MR. We P. PYCRAFT ON THE MORPHOLOGY 
reaches as far forward as the anterior limit of the choanz, and 
terminates immediately below the level of the anterior limit of 
the lachrymo-nasal fossa. 
The anterior end of the palatine in 2hea is widely separated 
from the palatal process of the premaxilla, while in the Tinamous 
the anterior end of the palatine just touches the free end of 
the palatal process of this. This connection is brought about, 
partly by the forward shifting of the palatine, and partly 
by the narrowing of the beak, consequent upon the lateral 
reduction of the maxillo-palatine process. 
We are now ina position to summarize the facts herein set 
down, and to select therefrom such as directly illustrate the 
transition from the Paleognathine to the Neognathine palate, 
which is the object of this paper. 
The most primitive arrangement of the Avian palatal bones 
is to be found in the skull of Dromeus. The vomer is here of 
great size, terminating posteriorly in a pair of rami, continued 
directly backwards beneath, and fusing with, the pterygoids. 
The palatines are connected, caudad, with the outer border of this 
vomero-pterygoid bar, and are widely separated one from another. 
Anteriorly the palatines are connected solely w the maxillo- 
palatine processes. 
In Rhea the vomer is relatively smaller, and the paired 
extremities are closely approximated, but are continued backwards 
as in Dromeus, beneath the pterygoids. The palatines have 
shifted inwards, losing their original connection with the outer 
border of the vomero-pterygoid bar, and, taking up a new position 
beneath this bar, have formed therewith a squamous suture. 
The approximation of the rami of the vomer towards the middle 
line has brought the distal end of the pterygoid into relation 
with the parasphenoidal rostrum. The distal extremity of the 
palatine is far removed from the palatal process of the pre- 
maxilla, and is connected wholly with the mesial border of the 
maxillo-palatine process. 
In the Tinamous, the vomer is still relatively further reduced, 
and does not embrace the parasphenoidal rostrum so completely 
as in Rhea. The relations between vomer and pterygoid are 
much asin Rhea. The palatines bound the feet of the vomer 
externally, and will be found to be connected with the pterygoid by 
an oblique and scarcely perceptible suture. By the reduction in 
