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SKULL OF THE AGITHOGNATHOUS BIRDS. 275 
young bird the palatine suture can be seen; but in the adults it is lost. The trans- 
palatine (¢.pa) is a flat spatula; and the interpalatines are well rolled over below as 
they pass into the postpalatine region (pt.pa). The ethmo-palatine shells are very 
large relatively ; they pass insensibly into the vomer; and the main bar is, as it were, 
twisted upon itself as it runs forward, first steep and then lying horizontally, where it 
passes by ankylosis (not as a rough joint as in the last) into the rostrum. The upper 
and lower faces of the pterygo-palatine arcade seem to be much alike (figs. 4 & 5); 
for both have a round large channel. Above, this is caused by the ascending lamin 
clasping the basis cranii, and below by the interpalatine lamine forming a wall, and 
almost a floor, to the nasal passage. The maxillaries pass into the jugal behind, and 
into the rostrum in front, insensibly; and the maxillo-palatine processes are as frail 
as in the last, but end in a flat pedate plate. 
The vomer, by trespassing far on the nasal territory, is enormous; it has lost its 
freedom behind; and in front it has lost the separateness:of its septo-maxillary ele- 
ments and has ossified a large tract of the nasal labyrinth (fig. 5). The upper part 
is very steep on each side of the septum (figs. 5 & 6, s.1, v), which is strongly ossi- 
fied, and has two series on each side of sinuous bony ridges, the hinder parts being the 
nasal-nerve bridges ; and the front ridges are where the alate part runs into the ale nasi 
(fig. 6, s.n, al.n). These ridges are strongly folded and bent upon themselves, and 
so also is the great alinasal turbinal (figs. 5, 6); and being ossified, we see in the dry 
skull a curious modification of these parts. 
Then, between the lateral dentate mass and that part of the alinasal region ossified 
by the vomer, there is a large, almost directly transverse synchondrosis. Hence we 
see that in the nasal labyrinth of Hstrelda, besides the centres for the hinder olfactory 
region (the septum nasi and the anterior part of the alz), the alinasal turbinals and the 
inferior turbinals are separately ossified from the hinder part, which has bony matter 
creeping far into it from the four vomerine bones. 
The outer face of the ale nasi, round the external nostril, is but little ossified. 
In Coccothraustes the olfactory and nasal nerve pass through the opposite ends of a 
shortish chink ; and outside this the pars plana, above, is deficient, the nasal bone being 
visible through it. In these Waxbills, especially HL. phaéton, that space is wide, and 
the nasal nerve passes separately through it. The top of the ecto-ethmoid projects 
normally; the pars plana is thick and spongy, with a round notch on its outer edge, 
a moderate foot, and no separate os uncinatum. I find no trace of a lacrymal in 
these types. 
Example 53. Skull of Green Linnet (Linaria chloris). Family Fringillide. 
Group Oscines. 
Habitat. Great Britain. 
Careful study of the skulls of various kinds of Finches leads me to cull out, as the 
VOL. X.—PaRT vI. No. 4.—June 1st, 1878. 2Q 
