STUDIES OF THE MA.CROCHIRES. 
321 
These latter structures will be alluded to again after completing 
the description of a palatine bone. 
The anterior half of a palatine is a narrow ribbon of bone placed 
horizontally, dilated at its further extremity, which, as has already 
been said, blends with the horizontal portion of the corresponding 
premaxillary. The posterior division of the bone feebly develops 
an inner and an outer carination, the “ postero-external ” angle 
being completely rounded off. 
In the median line, beneath the basisphenoidal rostrum, these 
palatine bones meet each other, and in front the vomer, for their 
entire lengths, a union which, in both T. mexicanus and T. puella, 
seems to amount to an absolute anchylosis. 
If this prove to be universally the case in the skulls of fully 
adult Trogons, it need not surprise us, for when we come to the 
Humming-birds there will be another peculiar anchylosis to be 
described that is occasionally to be found in their skulls. 
Now the vomer (fig. 8, v .) in both of these Trogons is a rather 
short subeylindrical rod with a bluntish point. This point rests 
directly upon the posterior free edge of the osseous nasal septum 
( n.s .). 
This intimate relationship between the vomer and nasal septum 
in the Trogons led the late W. A. Forbes into an error, which will 
be at once evident upon an examination of his drawing of these 
parts in Pharomacrus mocinno (P. Z. S. 1881, p. 837). At least 
it does not hold quite true in the species at hand ; and I suspect 
that Forbes, in examining alcoholic specimens, included this thin 
posterior edge of the nasal septum with the anterior tip of the 
vomer, giving it that “thin and filiform” appearance to which 
he alludes. This slight error might easily be made by that kiud 
of an examination, when in a dried skull, snch as I have before 
me, these parts would be better distinguished. His description, 
however, in the contribution above referred to, is a marked 
improvement upon that by Professor Huxley, which it was 
written to correct ; and the former writer was fully aware of the 
fact that the nasal septum in the Trogons ossified. In my 
specimen of T. mexicanus this plate has a large vacuity in its 
centre, while in T. puella it is entire. 
The tips of the maxillo-palatines do not show in the iuterpala- 
tine median space, upon this view of the skull, as they are said 
to do in P. mocinno by Forbes in the paper just quoted. (Com- 
pare figure in P. Z. S. 1881, p. 837, and fig. 8 of the present 
