PROF. W. K. PARKER ON GITHOGNATHOUS BIRDS. 323 
Example 13. Muscisaxicola mentalis. 
Habitat. Chili. Group “'Tracheophone,” Miiller; family “ Tyrannide.” 
This is a larger bird, and has a stouter face than the last; yet, on comparing the 
palates together, it is easily seen how near they are in nature. The character of the 
bony substance in the two is exactly alike, both in the cellular and in the fibrous parts ; 
it is of the most delicate kind. The basitemporal projects more at the mid line under 
the Eustachian opening (Pl. LIX. fig. 9, 4.¢, ew); and the posterior part of the para- 
sphenoid (pa.s) is not so thick. The hinge-notch is more perfect than in Synallaais, 
and the septum much deeper and more largely alate (Pl. LIX. figs. 9 & 10, 7); it much 
resembles that of Homorus (see Pl. LX. figs. 1-4), but itis deeper, as in Dendrocolaptes 
(Pl. LIX. fig. 3,s.”). The ale nasi are soft externally ; but their turbinals are ossified 
(fig. 9, a.tb), as is also the nasal floor (n. f.) and part of the recurrent fold (re. ¢). 
The inferior turbinals have patches of endostosis. On the whole, the anterior part of 
the palate is very much ossified for so small a bird. The vomer is large (figs. 9 & 10 v); 
and the inturned lamina (7. a. /), like the alinasal turbinal, is ossified by its own endosteal 
deposit, and articulates with the large swollen lobes of the vomer—that is, with its 
coalesced septo-maxillaries: this belongs to the 1st variety of “ complete desmognathism.” 
The bony septum, behind its large subnasal ale, is very solid and even bulbous; and it 
is almost embraced by the still more bulbous upper lobes of the vomer. The vomer is 
broad, flat, largely united at the mid line; and its flat crura are near together, and anky- 
losed to the ethmo-palatines. 
The likeness and the unlikeness of the next arch in this type and in Synallavis is very 
instructive, as showing very fine, and yet quite measurable and evident diversity. ‘The 
delicate, arcuate, ascending apex of the pterygoid (e.pg) has here its fullest ornithic 
growth ; the whole pterygoid (fig. 9, pg) is longer, more arcuate, and clings more closely 
to its fellow in front, where it sends upwards a flat, leafy lobe, which articulates in 
front with the mesopterygoid lobe of the palatine, once a separate bone. 
The postpalatine lamine are cut away, as it were, below; and the body of the bone 
is more spongy than in Synallaaxis; the prepalatal bars are equally delicate, and form 
one continnous and almost straight bar with the edge of the broad part and the retral 
transpalatine (¢.pa). The ethmo-palatal is dome-shaped, as in all these types. 
The investing bones are all ankylosed together; the maxillo-palatines (figs. 9 & 10, 
mx.p) are like pruning-hooks, and are somewhat pedunculate. 
The ecto-ethmoid is squarer than in Synallaais, its outer side being less concave, 
and its angle less developed; it is a flat, spongy plate, appearing moderately above, 
and having over its antorbital region a huge doorway from the orbit into the nasal sac, 
through which both kinds of nerve pass. 
Example 14. Homorus unicolor. 
Habitat. Mendoza, La Plata. Group “ Tracheophone,” Miiller; family “ Dendroco- 
laptide.” 
2x 2 
