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to Dinornis, the other to Palapterya. I subsequently discovered a type of leg and foot 
generically distinct from those which had been referred respectively to Dinornis and 
Palapteryx; and for that type I proposed the genus Aptornis, to which genus I was 
then led to refer the very remarkable skull figured in Pl, XLIII. 
Successive evidences of cranial characters of different species of Dinornis, from the 
largest downwards, were far from showing the distinctions which, in the skull of 
Aptornis, had originally led to a generic division of the larger extinct wingless birds of 
New Zealand; and accordingly, retaining the name Dinornis for the D. giganteus and 
allied species to which, as originally known by vertebra, pelvis, and limb-bones, that 
generic name had been applied, I was driven, after ascertaining their true cranial 
characters, to rest the distinction of Palepteryx on the presence of the small back toe, 
determined in the large robust species of the Middle Island (Palapteryx robustus), and 
its seeming absence in the more slender Dinornis giganteus of the North Island. Sub- 
sequently I was led to doubt the generic value which had been assigned to that 
reduced, not to say abortive, digit, probably variable as to its existence; and I gave 
up the application of the character, from the consideration that the ligamentous attach- 
ment might fail to leave sufficient indication on the metatarsal bone in some cases. ‘The 
range of variation in the cranial characters of species unequivocally of either Dinornis 
or Palapteryx did not appear to me to support a continuance of those generic sections ; 
and of late years I have, therefore, practically dropped “ Palapteryx,”’ and described 
additional facts and evidences of these extinct birds under the old generie term 
Dinornis. 
No doubt, apart from the Apterygian character of the back toe (é, fig. 1, Pl. XLIX.), 
if even it had been determined without question to be constantly present in certain 
species and absent in others, the singularly massive proportions of the limb-bones in 
such species as D. elephantopus and D. crassus might lead one, prone to generic sections, 
to found a genus for such strong-limbed birds. But D. robustus and D. maximus, with 
the series of Moas dwindling to a form smaller than any which I have yet described, but 
equally worthy of being named, illustrate the transitional steps in the derivation of such 
species, due to inherent tendencies operating independently of individual volitions, and 
under circumstances affording no obyious or intelligible selective influences. Guided, 
however, by the Linnean methods of making known these animated forms, and accepting 
genera as they stand in natural families of modern ornithological systems, the two well- 
marked modifications of sternum which I haye now been enabled to describe might 
justify the restitution of the term Pelapterya to such thick-limbed kinds as Pal. ele- 
phantopus, Pal. crassus, and Pal. robustus. 
In a collection of bones transmitted by Dr. Haast to the Royal College of Surgeons, 
and which were submitted, by his request, to my examination, there was a lot marked 
‘no. 16, fragments of sternum of Dinornis crassus,” and associated with a portion of the 
skeleton ascribed to the same species, ‘This lot contained portions of sternums of 

