296 PROF. W. K. PAEKER ON ^GITHOGNATHOUS BIRDS. 



and the styliform crura long and delicate ; the fore margin is clearly notched ; it then 

 suddenly widens, and on each shoulder there is a triangular snag with its projecting 

 base looking outward and fixed and grafted upon a sigmoid spatula of cartilage (v. c). 

 This compound lyre-shaped vomer is strongly attaclied to the nasal floor (al. n) by a 

 broad and short ligament composed of connective fibres. In the adult (fig. 9, v) the 

 angular snags have been segmented off as small " septo-maxillaries " {s.mx), the body 

 of the bone has become very thick, and the crura stronger. The inferior surface is 

 subcarinate, the superior scooped. Here the main difference between this vomerine 

 arrangement and that of the Passerines is, that the bony substance has affected the 

 cartilaginous segment, but not the nasal labyrinth. Yet the amount of metamorphosis 

 seen in these birds is greatly in advance of the pupal simplicity of the Rhea ; even where 

 the vomerine cartilage occurs in a high type, as in the Celebesian Woodpecker [Hemi- 

 lophus fulvus), there is no morphological union with the vomerine bones. 



The pterygo-palatine arch is very strong in its posterior half, and of extreme tenuity 

 in front. The suspensorial segment, " pterygoid " (figs. 1 & 9, pg), is not tip-tilted 

 as in most of the Coracomorphae, but agrees in this respect with the forms that lie 

 in its own lower stratum, the apex being compressed and bilobate, so as to abut against 

 the quadrate up to its orbital process. For the rest, its form is exactly that of a 

 Pigeon or Plover ; but it appears to be gallinaceous in one important aspect — namely, 

 that the mesopterygoid spur is fore-shortened, and is here formed into a crest, convex 

 without and concave within, where it forms a gliding joint on the swollen basifacial 

 beam (fig. l\,pg, pa.s). But in the young Ilemipodius varius it is a long separate bone 

 (fig. 13, ms.pg) ; and what is unusual is its coalescence with the pterygoid again, and not 

 with the palatine. This being the case, the narrow outturned postpalatine bar fits but 

 loosely to that beam, but converges to meet its fellow below it, to form a fibrous com- 

 missure, symmorphic of a very early condition of the lyriform trabecular arch. The 

 small " interpalatines," which are inbent snags, are of less extent than the overlying 

 ethmopalatine laminae, which articulate with the feet of the vomer (figs. 1 & 9, i.pa, 

 epa, v). Opposite these the palatines bend gracefully round to pass forward as the long 

 prsepalatine styles (pr.pa) ; there is therefore no rudiment of the " transpalatine angle ;" 

 yet the groove between the outer and inner edge on the lower face of the bone is rather 

 deep. In front these bones reach to the solid part of the praemaxillaries, and stretch 

 themselves in front of their chief splints, the maxillaries (figs. 1 & 9, ^jr.po;, ww). These 

 latter bones are simple models, out of which, by further extension of bony matter, the 

 maxillaries of any kind of " Carinate " bird might be evolved. Each frail bony bar has 

 the usual processes and parts, namely : — the main or dentary portion, fish-like in lying 

 within the prtemaxillary ; the ascending facial process, which articulates with the 

 descending crus of the nasal (fig. II, n.tnx) ; the conjugational " maxillo-palatine " hook 

 (mx.p) ; and the retral jugal style {j. mx), or zygomatic process. 



In the young Turnix (fig. I, ?jm'.^) the former are very slender styles, blunt-pointed 



