364 PROFESSOR OWEN ON THE GENUS PALAPTERYX. 



of the alveolar border, opposite the anterior border of the palatal aperture, emerges 

 forwards and upwards towards its fellow on the opposite side, gains the under sur- 

 face of the nasal process, and again diverging, terminates in its outer margin, defining 

 sharply in its course the anterior boundary of the outer nostril (n, fig. 5), in front of 

 which the smooth surface expands to the rough perforated bone forming the extremity 

 of the premaxillary : the root of the nasal process is still defined upon this part by 

 lateral grooves (n g), as in the Emeu, the Rhea, the Ostrich, and also the Apteryx, 

 notwithstanding the unusual prolongation of the body or rostral part of the premaxil- 

 lary in that bird. The back part of the nasal process is grooved between the two 

 curved ridges ; the under part of the process presents a median ridge (22', fig. 5). 



The corresponding extremity of the under jaw differs in a greater degree from that 

 in the existing Struthionidce, the symphysis being concave above from side to side 

 instead of flat (fig. 7). This specimen agrees so closely in size, in colour, in the 

 character of the perforations, and especially by the distinct alveolar edge and inferior 

 parallel symphysial grooves, with the corresponding extremity of the premaxillary bone 

 (22, figs. 2 & 3), that I am led to believe it to have formed part of the same beak. 

 The outer part of the alveolar border, moreover, is convex, adapted to the groove in 

 that part of the upper jaw, and the inner part is grooved and reciprocally adapted to 

 the convex inner border of the alveolar groove above. Notwithstanding the difference 

 in the depth and semicylindrical curve of the symphysis of Palapteryx from that of the 

 existing Struthionida, it presents on its under part the two characteristic parallel longi- 

 tudinal grooves (s^, fig. 6) which mark out the median prominence on that part. The 

 line indicative of the harmonia of the splenial piece is obvious on the under margin of 

 each ramus. The rami are thicker and deeper anteriorly (fig. 1 sg) than in the Ostrich 

 (PI. LIII. fig. 5). The grooved alveolar border terminates behind, two inches and a half 

 from the end of the jaw : the outer side of the jaw presents a deep vascular groove 

 beneath that border, which ends in foramina at the beginning of the coarsely perforated 

 symphysial extremity : the contour of the alveolar border is gently convex, and the 

 under border of the same part of the ramus correspondingly concave ; behind this part 

 the upper border becomes concave and the lower one convex, the whole ramus of the 

 jaw having a sigmoid flexure : the upper border behind the alveolar portion becomes 

 rounded and thinner, while the lower border below increases in thickness. The longest 

 portion of the ramus reaches nearly three inches and a half from the end of the sym- 

 physis : there is a large groove and perforation close to the broken end on the outer 

 side : the lower jaw was probably from five inches to five inches and a half in length, 

 and was shorter in proportion to its breadth and depth than in the Ostrich, or perhaps 

 the Emeu, if we may judge from the extent of the alveolar ridge, and from the early 

 flattening of the nasal process of the premaxillary. The angle of divergence of the 

 mandibular rami is the same as in the Emeu. 



From the above-described characters of the cranium and portions of jaws figured in 



