312 PROF. W. K. PARKER ON ©GITHOGNATHOUS BIRDS. 
give this part of the head a very crocodilian aspect. ‘The spongy znner part of the pars 
plana (fig. 6, p. p), however, is of small vertical extent, as in Pipra; and the nerve-pas- 
sages run freely into each other. Part of the alinasal is ossified on the outside round 
the external nares (figs. 6 & 7, al.n); this gives, in the dry skull, a notched appear- 
ance to these wide passages. The small semi-lacertian inferior turbinals are ossified by 
endostosis. Every thing hitherto shows Pachyrhamphus to be a very generalized bird in 
its own great family or suborder; the lower palatine structures will yield like evidence. 
The pterygoids (fig. 4, pg) are stronger and more arched outwards than in Pipra; but 
the epipterygoid spur is bound close to the front of the quadrate, as in the Turnicide 
and Gallinacee. The whole bar, by ankylosis, has relapsed into unity; for the ptery- 
goid, mesopterygoid, and palatine have lost all their sutures (fig. 6, py, e.pa, ms.pq). 
Between the postpalatine descending lips (pt.pa) there is more of the parasphenoid 
seen than in Pipra; and these inferior lip-like lamine soon cease, passing into the inter- 
palatine spikes (fig. 4, 7.pa), which are spongy and have ragged edges. 
The body of the palatine is but little bowed, and sends only a few toothlets back- 
wards as rudiments of the transpalatine region (¢.pa); thence the bar is narrow, feeble, 
bowed in, and then curved outwards a little before it ends, converging towards its 
fellow. The upper lamina or ethmo-palatine (fig. 6, e.pa) is of the same extent ; but 
its spike, ankylosed to the vomer, is smaller than that of the lower or interpalatine 
lamina. 
The premaxillaries and maxillaries together form an elegant leaf-like rostrum (figs. 
4, 6, 7), not unlike that of the Boatbill (Cancroma). The whole structure is extremely 
light, and coarsely spongy ; and the coalescence of the maxillaries, premaxillaries, nasals, 
and jugals is all but complete; a little remnant of the suture is seen above the hinge. 
On each side, close inside the angular process of the preemaxillary, are seen the large, 
broad-based, struthious, maxillo-palatine processes (figs. 4 & 5, ma.p): these are pneu- 
matic, somewhat hooked, and bind by their inner edge on to the downturned shoulder 
of the vomer. These processes also show that this form is more generalized than Pipra; 
the palatines and septum nasi show the same thing. 
Example 6. Thamnophilus doliatus. 
Habitat. Guiana. Group “ Tracheophone,” Miiller; family “ Formicariide.” 
This strong-billed bush-bird shows the ‘‘ Formicariide ” to be on the same ornithic 
level as the “ Cotingide.” They have both cleared the turnicine boundary dy a long 
distance; but they are metamorphosed in the face much less than the typical Crows, 
Warblers, and Finches. A mere glance at the figures (Pl. LVII. figs. 1, 4, 8) of the 
palates will show how near Thammnophilus comes to those last described, especially to 
Pachyrhamphus; in some respects this form comes nearest to the Hemipods, in others 
the latter. 
The basitemporal and parasphenoidal regions are precisely like those of the “ Cotin- 
