§ 
chypteryz, in which, as in all small birds, the cerebral hemispheres, 
as requiring a certain bulk for their functions, do not decrease in 
the ratio of the size of the body, the upper surface of the cranium 
is raised by the hemispheres beneath into a smooth convexity. 
The Notornis is a large modified form of the same natural family 
of the Gralle as the Porphyrio and Brachypteryx, and from the form 
of its sternum it must have been, like the latter peculiar bird of New 
Zealand, deprived of the power of flight. 
The fourth genus of bird indicated by portions of the skull in Mr. 
Walter Mantell’s collection was referable to the family of Parrots 
(Psittacide), and amongst these to the genus Nestor. The bony 
portion of the upper beak—the only part of the skull preserved—by 
its deep, subcompressed, curved and pointed form, its seeming solidity, 
pierced by small subcircular nostrils close to its base, attested the 
family character; whilst the proportional length as compared with 
the depth, the narrow upper surface to where it suddenly expands 
above the nostrils to join the cranium, the absence of the notch on 
the under border, the very narrow elongated triangular palatal sur- 
face, with the median linear notch at its base,—all demonstrate that 
in this characteristic part of the skull the New Zealand bird repre- 
sented by it most resembled the genus Nestor,—a singular nocturnal 
Parrot at present only known as a denizen of that island. 
Thus then it appears that the indications of two genera, with 
several species of terrestrial birds of large or gigantic size, deduced 
in the Author’s former Memoir (Part II.) from bones of the legs, are » 
most fully and satisfactorily confirmed by the evidence of the subse- 
quently received bones of the head and beak. 
The form and structure of these characteristic parts in one of the 
genera (Dinornis) are so peculiar, that the author does not refer the 
genus to any known natural family of birds. Its location in the 
order Struthionide implies little more than an arrested development 
of wings, and an exaggerated development of legs, organized for 
progression on dry land. 
As, however, there are strictly aquatic forms of birds deprived, by 
a low development and special modification of the wings, of the power 
of flight, so also there are, in other natural groups of birds, aberrant 
forms similarly debarred from the privilege and enjoyment of the 
characteristic kind and field of locomotion of their class. Apart from 
the true Struthionide, we have an instance of this in the Brachy- 
pteryx or modified Rail of New Zealand ; the Dodo is a second in- 
stance, whether it be regarded as an aberrant Vulture or a modified 
Pigeon, according to the views entertained by Mr. Gould and sup- 
ported, with new arguments, by Mr. Strickland, before the British 
Association at Oxford, and which will be fully elucidated in the 
_ forthcoming work on the extinct flightless birds of the Mauritius and 
neighbouring isles, which Mr. Strickland is about to publish in con- 
junction with Dr. Melville. 
With regard to the natural group or family of birds to which the 
Dinornis, with its adze-like bill and crocodiloid cranium, may be re- 
ferable, the author pointed out several marks of resemblance in the 
