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coeval. Numerous fragments of the shells of more than one kind of 
egg, the largest surpassing in size the egg of the ostrich, had also 
been discovered with the bones. 
In the present memoir Prof. Owen described the bones of the head 
and beak. They belonged to four distinct genera of Birds. The 
largest skull, with a very strong, broad, subelongate and subincurved 
beak, like an adze, was referred to the genus Dinornis. ‘The second 
in size, with a beak to which that of the Emeu makes the nearest ap- 
proach, was referred to Palapteryxz. The third skull, with a beak 
like that of the Porphyrio and Brachypteryx, was referred to the same 
family—‘ Rallide’—to which those genera belong; but, through the 
peculiarities of the cranium, formed the type of a new genus, Notornis. 
The fourth form of beak was referable to the genus Nestor in the 
family Psittacide. 
The cranium of the Dinornis presents the family characters of great 
breadth, and forward inclination of the occipital region, of the ver- 
tical plane of the occipital foramen, and of the prominent and pedun- 
culate occipital condyle ; but the downward development of the basi- 
occipital and basisphenoid is exaggerated, as compared with the 
Palapteryx, the basis cranii, which is 2} inches in length, descending 
abruptly for the extent of 1 inch below the foramen magnum ; the 
condyle is hemispherical as in Otis, not a quarter of a sphere as in 
Struthio and Palapteryz, nor, as in Didus, a transverse reniform tu- 
bercle with a median notch above. The foramen magnum is a ver- 
tical ellipse, with lateral processes encroaching upon it, as in Didus ; 
but in this large extinct bird the upper half of the foramen is nar- 
rower and almost pointed above. In Apteryx and Palapteryr the 
foramen is widest transversely. The margin of the foramen magnum 
is broad and excavated in both Dinornis, Otis and Didus, but the 
upper border ends in the latter genus in a tubercle on each side. 
In Didus there is a small middle supraoccipital foramen and two 
lateral ones, but these do not exist in Dinornis, Otis, or Palapteryz : 
the lateral foramina are present in Apteryz. 
In the extinct genera and in Otis the supraoccipital ridge is well- 
marked, but defined rather by the subsidence of the occipital surface 
than the elevation of the ridge above the parietal one. 
In no bird is the extent of surface for muscular attachment so great 
at the back part of the head, or so strongly marked by depressions 
and ridges, as in the Dinornis. 
The extension of the surface by the downward thick wedge-shaped 
development of the basi-occipito-sphenoidal surface, and by its lateral 
strong backwardly produced ridges, is quite peculiar to the Dinornis. 
An approach to this structure is made by Ofis in the ridges that con- 
nect the sides of the flat basisphenoid* with the paroccipital * pro- 
cesses. In Palapteryx the basi-sphenoid is square and flat below, in 
Didus it presents a longitudinal channel bounded by parallel lateral 
ridges; the sides of the basisphenoid, which incline to these ridges, 
* For the definition of these and other anatomical terms the author referred to 
his ‘ Report on the Homologies of the Vertebrate Skeleton’ in “ Report of British 
Association, 1846.” 
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