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t 
regard to its slope, as in the Argala and Ostrich: the occiput in the Apteryx is nar- 
rower, higher, almost vertical, with the middle part produced backwards into an angular 
projection and perforated on each side: the upper region of the head is much more lofty 
and convex than in the Dinornis ; the mastoid process is much smaller in proportion to 
the par-occipital process : the temporal surfaces resemble those in the Dinornis in their 
antero-posterior extent, but do not impress the sides of the cranium ; the orbits are much 
smaller, and the olfactory cavities much larger in the Apteryx than in the Dinornis ; 
but it is interesting to find the nearest approach to these peculiarities of the existing 
Struthious bird of New Zealand made by the extinct Struthionide of the same island. 
The cranium of Dinornis, referable by its size to the D. dromioides, was kindly trans- 
mitted, with other bones of the same genus, for my examination by Mr. Swainson*. 
It has suffered nearly the same kind and degree of mutilation as the larger cranium ; 
the basi-sphenoid, with all the rostral part of the skull, having been broken away ; but 
the supra-orbital ridges and fore-part of the frontal region of the cranium are more entire 
(Plate XXXI. figg. 4—6). The breadth of the cranium across the mastoids is two 
inches, seven lines ; the length to the anterior border of the os frontis (not entire in the 
larger specimen) is two inches, eight lines ; the breadth across the post-orbital angles is 
two inches, two lines; the breadth between the temporal fossz is one inch, nine lines. 
The smaller size of the present cranium, as compared with the preceding specimen, 
does not depend upon the immaturity of the individual : not only are the sutures almost 
as completely obliterated (and this takes place much later in Struthious birds than in 
birds of flight), but the ridges defining the attachment of the muscles are as strongly 
marked, and indicate not only a full-grown but an old bird. 
The large size and vertical plane of the foramen magnum; the broad, low, supra- 
occipital region (figg. 4 & 5, 3), sloping from below upwards and forwards ; the almost flat 
parietal surface (7b. 7), continued directly forwards into the broad, downward sloping 
frontal region (ib. 11) ; the wide and deep temporal fossz (vb. 6) ; the small orbits (7b. 11') 
and expanded olfactory chamber (fig. 6, 18) ;—all repeat the peculiar generic characters 
of the cranium of Dinornis which are exhibited in the larger specimen. 
The specific distinction of the smaller cranium is shown by the less produced and 
sessile occipital tubercle (figg. 4 & 5, 1); by the absence of the two fossz on the back- 
part of the descending plate of the basi-occipital ; by the wider temporal fosse, divided 
behind from the occipital surface by a common ridge (fig. 5, r), not by a flattened tract ; 
—and if the value of this difference should seem to be diminished by the known changes 
in the development of the temporal muscles in the progress of age, it applies in the 
present instance in favour of the specific distinction of the smaller cranium ; for the less 
* In the note accompanying the specimens that eminent Ornithologist says, “They are from the North 
Island...... I have no idea that this strange group of Birds is any longer in existence, notwithstanding all 
the stories of the natives and others, If any may be alive they will probably be found in the Middle Island, 
which may be almost said to be uninhabited, except on the coast.” 
