312 PROF. W. K. PABKEE ON ^GITHOGNATHOUS BIRDS. 



give this part of the head a very crocodilian aspect. The si^ongy inner 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 moi'e arched outwards than in Pipra ; but 

 the ejiipterygoid spur is bound close to the front of the quadrate, as in the Turnicidse 

 and Gallinacete. The whole bar, by ankylosis, has relapsed into unity ; for the ptery- 

 goid, mesopterygoid, and palatine have lost all their sutures (fig. 6, 2^g, e.pa, mspg)'. 

 Between the postpalatine descending lips {pt-pa) there is more of the i^arasphenoid 

 seen than in Pipra ; and these inferior lip-like laminse soon cease, passing into the inter- 

 palatine spikes (fig. 4, I'.jja), 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 [tpa) ; 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, epa) is of the same extent ; but 

 its spike, ankylosed to the vomer, is smaller than that of the lower or intevpalatine 

 lamina. 



The prsemaxillaries 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, prcemaxillaries, 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, mx.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 " Tracheophonse," Miiller ; family " Formicariidffi." 

 This strong-billed bush-bird shows the " Formicariidee " to be on the same ornithic 

 level as the " Cotingidse." They have both cleared the turnicine boundary hy a long 

 distance; but they are metamorphosed in the fiice 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 Thamnophilus 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- 



