114 MR. W. K. PARKER ON THE STRUCTURE 



its edges can be seen in an upper view (Plate XXI. fig. 10) projecting beyond the nasal 

 processes of the premaxillaries and upper spur of the nasals, and in the lower view 

 (fig. 8) above and in front of the vomer. But the rest of the trabecular part of the 

 septum nasi is absorbed, and only its nasal part is retained ; it is bony, and the bony 

 matter passes a short distance into the paired " alae " (figs. 8 & 10). As to the secondary 

 or splint-bones of the trabecular arch, I have already spoken of the parasphenoid : the 

 others are, in this case, the premaxillaries and the vomers. The former (fig. 8, px) 

 appear very small on the lower surface, but above (fig. 10) each half is seen to be equal to 

 the corresponding maxillary, and to overlap it, as in birds generally and Teleostean Pishes. 

 The dentary margin, however, does not reach nearly so far back as in birds generally, and 

 this double bone is omithically very small. 



The other double bone is the vomer. This is a long bar of spongy bone, rather bluntly 

 pointed at the fore end and sharp behind (figs. 8 & 9, v) ; it is quite distinct from the 

 overlying ethmo-palatal bars in newly fledged birds (fig. 9) ; but in the adult (fig. 8) it 

 becomes a derived commissural band to the palatine arch, as in a large number of birds, 

 notably the " Coracoinorphae." 



Plat above, where the palatal bars lie upon it (fig. 9, v, epa), the vomer is carinate below 

 throughout its entire length (fig. 8). In the younger (pin-feathered) fledglings I found 

 the vomers distinct throughout their whole length (Plate XXII. fig. 1, v). They were 

 long styles, approximating very closely in front, and gently diverging behind. They 

 were seen to have been formed by ossification of a fibrous and not a cartilaginous tract. 

 In more mature fledglings the fore ends had united (Plate XXI. fig. 11, v), and the 

 hinder ends were still more divergent. These again approximate, ankylosis takes place 

 thoroughly fore and aft, and the inferior surface ossifying, the interpalatine " raphe " 

 acquires its long keel. The fore end of the vomer in the adult (fig. 8) becomes rounded, 

 losing the beaked form it had in the newly fledged bird (fig. 9), and at this part below 

 the maxillo-palatine hooks (mxp) are notched on their inner margin to articulate with 

 this extremity of the vomer. A character like this gives the palate a very " iEgitho- 

 gnathous " appearance, as this curious articulation, which bridges over the chink on each 

 side, is often seen in southern " Ooracomorphse," both those of low and also of a high 

 type, as in Grallaria, Thamnophilus, Dicrurus, Dendrocolaptes, Homorus, and Gvmno- 

 rhina. But I have already said that these vomers are membrane bones ; and I here show, 

 in three stages, the longish ligament which binds the vomer to the internal alinasal 

 wall with its long worm-like turbinal (Plate XXII. fig. 1, and Plate XXI. figs. 9 & 11, 

 aln,v). In the second of these three stages (fig. 11), the in turned alinasal wall is seen 

 to lie on the broad maxillo-palatine ; but it stops far short of the vomer, which also fails 

 to spread its shoulders towards the cartilage. 



The palatine arch of the Pern-Owl equally departs from the Coracomorphous type, and 

 cleaves to what is signally Cuculine — I mean, in the broad sense of that word. 



It has been already shown that the distinctively Passerine or Corvine character of the 

 palatine is the metamorphosis of the primary bar into four pairs of true morphological 

 endoskeletal elements, to say nothing of the secondary bones. But in Caprimulgus, my 

 youngest specimen (Plate XXII. fig. 1) only shows a trace of true cartilage on the edge 



