62 PROFESSOR OWEN ON THE GENUS DINORNIS, 
The chief difference which the skull under consideration presents as compared with 
that figured in pl. 54, vol. iii., is the greater relative extent of the osseous body of the 
premaxillary, and of its downward curvature, in which it resembles in the same degree 
the skull presumed to be of the Dinornis figured in pl. 52, vol. iii. 
From the remarkable modifications of the back part of the cranial portion of that 
skull, its generic distinction from the large skull under consideration is evident ; and 
if we refer the present large cranium to the genus Dinornis, distinguished as it is by its 
superior extent and curvature of the bony beak from the skull referred to Palapteryz, 
then the still more remarkable skull figured in pl. 52 might possibly belong to the 
genus Aptornis, of which the equally remarkable bones of the legs have been described 
and figured in a preceding Memoir’. It seems, however, to be too large for those 
small metatarsi. 
The skull of, perhaps, a larger species than the subject of the previous description, is 
indicated by the hinder half of the cranium (Pl. XXIV. figs. 1, 2 & 3), which, by the 
persistency of the sutures, the absence of the superoccipital and temporal ridges, and 
the smooth exterior of the bones, has belonged to a young individual of, it may be, the 
Dinornis giganteus. The occipital condyle (ib. fig. 2,1) is larger than in the older skull ; 
the elements of the occipital bone have coalesced: but the lambdoidal suture dividing 
the superoccipital (3) from the parietals (7), the sagittal suture (s), and that dividing the 
parietals (7) from the mastoids (8), and both these from the alisphenoids, remain. Not 
any of these sutures are dentated ; they are more properly ‘ harmoniz’: the sagittal is 
the most irreguiar or wavy. The particular form of the cranial bones of the Dinornis is 
indicated by these sutures. 
The superoccipital (3), as in the skull last described, deviates most, by its great breadth 
and small height, from that in other birds: the middle and major part of its anterior 
margin is slightly convex, or subangular forwards, the outer parts notched for the recep- 
tion of the posterior external angles of the parietals: yet, notwithstanding the little 
elevation of the superoccipitals, it reaches the level of the upper surface of the cranium, 
owing to the flatness of the parietals: it slopes forwards at once from the upper border 
of the foramen magnum. The broad paroccipitals (4) spread outwards and backwards, 
and nearly attain the level of the upper surface of the cranium. 
Each parietal terminates behind in an obtuse angle, which penetrates a corresponding 
emargination in the superoccipital near its outer angle; and it sends a rounded pro- 
jection from its anterior border, near its outer angle, which enters a corresponding 
emargination between the frontal and postfrontal. The outer part of the parietal 
bends down, forms the bottom of the temporal fossa, and meets the alisphenoid near 
the lower part of that fossa at a straight longitudinal suture. The tumid mastoid (s) 
forms the outer and posterior angle of the upper surface of the skull, as in the Crocodile, 
and is wedged between the parietal, superoccipital, alisphenoid, and tympanic bones, 
' Zool. Trans. vol. iv. p. 11. pl. 3. figs. 5-8. 
