PROFESSOR OWEN ON THE GENUS NOTORNIS. 369 



I may be excused for occupying a few moments in pointing out the differences ob- 

 servable in those birds that, resembling the Notornis in size, come nearest to it in the 

 structure of the beak. 



The depth, the degree of compression and the upper convexity of the strong bony basis 

 of the upper bill of Notornis, with its almost basal perforation by the nostrils, remind us 

 of some of the characters of the great Maccaw's beak ; but, besides the absence of the 

 terminal hook, the superior size of the nostrils, in Notornis, the absence of the bony 

 septum narium, and the grooved and perforated palatal surface of the premaxillary, are 

 essential deviations from the parrot-type of beak. It approaches more in shape to the 

 upper beak of the Raven, but it is less curved, deeper and more compressed, and the 

 sides are more vertical ; the nostrils are also smaller, and the palatine surface of the 

 Raven's premaxillary is entire, gently hollowed out, with a mediau ridge instead of a 

 groove. The Porphyria in every particular save size much more closely repeats the 

 characters of the skull of Notornis ; and the affinity is equally decisively marked in the 

 form and structure of the lower jaw. Of this part of the Notornis, the entire ramus of 

 the right side and the whole of the symphysis have been fortunately preserved. The 

 posterior articular expansion presents above an irregular transverse subrhomboidal 

 cavity, with a narrow and long articular surface {x, fig. 13) extending along the outer 

 and hinder border ; and the shorter and broader articular surface (z) at the fore-part of 

 the deep central depression. The inner angle rises almost vertically : it has a small 

 pneumatic foramen (pn) -. the back part of the enlargement presents an almost flat, 

 irregular, triangular, shghtly concave vertical surface ; the lower angle (so) curves down- 

 wards and forwards below the lower border of the ramus. The surangular (29', fig. 7) 

 supports a low coronoid process, whose base reaches from the articular enlargement to 

 near the beginning of the sharp alveolar border : its truncated summit has two small de- 

 pressions on its outer side ; they are deeper parts of a more extensive external muscular 

 impression, bounded below by a line reaching nearly to the lower border of the ramus. 

 This border (fig. 12) is smooth, convex, and of uniform thickness ; it describes a gentle 

 sigmoid curve, convex on leaving the deflected angle, concave where it joins the sym- 

 physis {s, fig. 7). The coronoid region has three perforations ; the posterior one {w) is 

 a small vertical oval, the anterior (m) is a longer longitudinal ellipse, and immediately 

 behind this is a linear fissure, which marks part of the lower boundary of the sur- 

 angular (^g')- All the elements and both rami of the jaw have coalesced. 



The upper border of the ramus is convex, and a little thickened between the coronoid 

 and the beginning of the sharp alveolar ridge : this is continued to the point of the sym- 

 physis, ss, which is more than one-third the length of the jaw ; and the alveolar ridges, 

 in gradually converging to the almost pointed termination of the mandible, describe 

 the gentlest curves convex upwards and concave outwards. The lower border of the 

 symphysis (fig. 12, s s) is smooth and convex from side to side, and extends in a straight 

 line from the back part of the symphysis obliquely upwards to the apical extremity of 



VOL. III. — PART v. 3 E 



