366 PROFESSOR OWEN ON THE GENUS NOTORNIS. 



lower jaw, the proportions of which, as compared with that of the Ostrich, may be 

 inferred from the lower jaw of that bird placed by the side of that of the fossil in 

 PI. LIII. fig. 4. The articular end presents a large triangular expansion, with a deep 

 irregular excavation above : in this excavation are two articular surfaces for the lower 

 condyles of the tympanic, one (x) long, narrow and shallow, following the external 

 border of the expansion ; the other (z) shorter, broader and much deeper, crossing the 

 inner side of the great concavity, describing a semicircle lengthwise, but flat or slightly 

 convex crosswise, with a well-defined semicircular edge at its outer and anterior end. 

 The hinder subvertical ridge of the expansion is less produced than in the Ostrich or 

 Emeu ; the outer articular surface extends to it in the fossil, but stops short in the 

 Ostrich. The inner and lower angle forms a short obtuse process. The inner articu- 

 lar cavity in the Ostrich and Emeu is angular, not curved. The surangular and 

 angular pieces are separated, in the present specimen, by a longitudinal vacuity reach- 

 ing to the fractured end of the fossil (fig. 1) ; the outer side of the angular piece here 

 shows the smooth depression for the lower piece of the bifurcate end of the dentary. 

 The articular, angular and surangular pieces have coalesced. 



Notwithstanding the superior size of this fragment of jaw to the corresponding part 

 of the Ostrich, it seems not sufficiently large for the proportions of the gigantic species 

 of Dinornis, and is more probably referable to the Palapteryx ingens. 



Cranial characters of the genus Notornis. 



The third genus of bird, for which I would suggest the name Notornis^, is indicated 

 by a nearly entire skull, giving, besides the characters of the cranium, the form of the 

 beak and the position and size of the external nostrils (PI. LVI. figs. 7 — 13). 



The cranium is of the size of that of the large Maccaw, which I adduce for this 

 comparison because it is one of the few existing birds with a broad sloping occiput 

 and with backwardly bent paroccipitals, as in the present specimen ; which, however, 

 in the breadth and slope of the occiput more closely adheres to the type of the 

 Dinornis and Palapteryx, having the plane of the foramen magnum (o, fig. 10) vertical, 

 the prominent hemispheric condyle (i) projecting beyond it, the basioccipital(i, i") extend- 

 ing below it further down than in the Maccaw or Apteryx, but proportionally less than in 

 Palapteryx. The cranium which presents the closest accordance with the one under 

 consideration is that of the Purple Coot or Sultana {Porphyria), with which, therefore, I 

 shall more immediately compare the present fossil. The basisphenoidal surface (s, fig. 9) 

 is flat, but pentangular as in Porphyria (5, fig. 3), the anterior angle projecting below 

 the base of the presphenoid (9) ; there are no pterygoid processes in either genus ; a 

 slender ridge (s', fig. 9) is continued from each paroccipital to the lateral angles of the 



' Gr. yuros south, opvis bird. 



