326 PEOP. W. K. PARKER ON ^UITHOGNATHOUS BIRDS. 



as a key than the far-western Homorus ; for in Gymnorhina, ossification runs riot, and 

 the very numerous osseous centres melt into each other, if not here, yet there ; at some 

 point or extremity, or jutting snag, they lose their individuality, making the morpho- 

 logist wonder why this puzzle grew from so many pieces. The notch in the basifacial 

 axis is a very large triangle, with its apex upwards ; it is perfect, and the point of the 

 parasphenoid does not reach it. In front of the notch, or hinge, is the well-ossified nasal 

 septum, which is fenestrate and deep in front, and shallow behind ; and its lower edge 

 and subnasal alse are ankylosed to the intensely ossified nasal floor (fig. 5, n.f) ; and 

 this is a continuation of the solid, bony alinasal. Where they arise, there the alinasal 

 turbiuals are ossified ; for the rest, they are soft, save at the end, where the upper 

 vomerine lobes (figs. 5 & 6, v) have run into them, by grafting (fig. 7, v, i. a. I). So also 

 tlie alisej)ta] has coalesced by bony union with the outer facial walls, as in the mammal, 

 and has also, as in the young mammal, a top-shaped bone, formed by ossificaticn of its 

 posterior end, the part attached to the bony " pars plana." Hence, in seeking in the 

 adult for the "trabecula; cranii," we find that foremost facial arch metamorphosed into 

 a great variety of substructural bars and beams and outgrowths of periosteal bone. 

 The apices of the two early coalesced bars are involved in the great " temporal wings of 

 the parasphenoid," forming the "anterior tympanic recess" (fig. b,a.t.r); then the 

 narrowing portion forms the sides of the sella turcica; narrowing still, it forms the base 

 of the interorbital fenestra, where the two primordial bars first formed their commis- 

 sural union. 



A continuation of this part substructs the septum between the functional part of the 

 nasal sacs — the perpendicular ethmoid ; there the notch severs the once double bar, 

 and the rest of the trabeculse form the base of the partition between the vestibular 

 parts of the nose and also, where the trabeculte keep flat, the floor of the nose between 

 the outer nostrils. The azygous process of the trabeculse (the praenasal cartilage) is 

 absorbed, being aborted by the huge splints formed upon it, as upon a model : I refer 

 to the foremost facial splints, the praemaxillaries. Yet this does not exhaust even the 

 '• endo-skeletal " parts of this arch ; for the lateral ethmoid has a small os uncinatum 

 (fig. S,2}.]}, 0. u) attached to its lower angle; this is the conjugational bone between 

 the two prseoral arches. 



1 have spoken of the dense and everywhere ankylosed prsemaxillaries ; these are the 

 foremost splints: but five more secondary ossifications belong to the trabecular arch; 

 these form a single bone in the adults. But these five osseous elements were brought 

 into relation with a pair of " vomerine cartilages." All these things are hidden in the 

 curious three-horned vomer of the adult ; and this now single bone has lost its freedom, 

 being bound to the ascending plates of the palatines behind, and grafted upon the ali- 

 nasal turbinals in front (fig. 5, i', e.pa ; figs. 6 & 7, «, i. a. I) ; also it is articulated strongly 

 .by a kind of zygapophysis to the maxillo-palatine on each side (figs. 5,6, 7, v, nix.p). 

 The stones and the cement used in this building, the strength and safety of which have 



