SKTJLL OF THE ^GITHOGNATHOUS BIEDS. 275 



yoimg bird the palatine suture can be seen ; but in the adults it is lost. The trans- 

 palatine (f.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 laminse 

 clasping the basis cranii, and below by the interpalatine laminse 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. n, 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 alse 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 vomei-, there is a large, almost directly transverse synchondrosis. Hence we 

 see that in the nasal labyrinth of Estrelda, besides the centres for the hinder olfactory 

 region (the septum nasi and the anterior part of the alse), 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 alse nasi, round the external nostril, is but little ossified. 

 In C'occotkraustes 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 E. phaeton, 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 Fringillidse. 



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 Isf, 1878. 2q 



