286 
thickness of 2 lines; and the fracture exposes the same open pneumatic diploé as in 
Dinornis. This process is distant from the back part of what remains of the paroc- 
cipital process 1 inch 3 lines. It is consequently nearer that process, being more 
backwardly situated, than in Dinornis robustus or D. elephantopus. But the Moas 
differ among themselves in this respect, according to, or with concomitant differences 
in, the antero-posterior extent of the temporal fosse. Thus Dinornis rheides more 
resembles Dasornis in this respect. But in the proximity of the postfrontals to the 
occiput Dasornis still more nearly resembles Struthio; and the resemblance extends to 
a concomitant large expanse of the superorbital arch. 
Again, we find in what is preserved of the fore part of the cranium a marked departure 
from the dinornithic type, and an adhesion as well marked to that of existing Struthio- 
nide. The fore half of the interorbital part of the frontals is contracted, as in Rhea 
and Dromaius, and is concave transversely, as in Shea, To its sides articulate the 
broad hind parts of a pair of bones which I regard as homologous with the two distinct 
nasals in Rhea and Struthio. These parts of the nasals, beginning narrow, or by a 
point, behind, rapidly expand and meet as they advance, so as to give a pointed form to 
the included part of the calvarium. Whether this part be the frontal, or an exposed 
surface of the connate prefrontals, the abraded surface of the bone does not permit to 
be defined with certainty. . 
The structure of this interesting fossil, as far as it can be defined, shows it to be of 
a bird; its configuration and proportions exemplify combinations of dinornithie and 
modern struthious characters. What the mandibles may further prove, time, we will 
hope, may discover. But this I anticipate with confidence, that further acquaintance 
with the osseous structure of Dasornis will show it to be no exception to the flightless 
and terrestrial nature of all other known birds of like hugeness. 
The present evidence of such a bird in so old a tertiary deposit as the London Clay at 
once recalled the discovery of the limb-bones of an equally gigantic bird by M. Gaston- 
Planté (tibia) and by Professor Hébert (femur) in the lower conglomerate of the eocene 
plastic clay at Meudon, near Paris. For the conclusions to which the study and comparison 
of these bones led me, I would refer the paleontologist to the Memoir quoted below’, to 
which M. Alphonse Milne-Edwards has done me the honour to refer®. I will only add 
that the main part of the shaft of the fibula of Gastornis has been more recently dis- 
covered in the same formation at Passy, near Paris*, which exhibits as extensive a con- 
* «On tho Affinities of the large Extinet Bird (@ustornis parisiensis. Hébert), indicated by a fossil femur 
and tibia discovered in the lowest eocene formation near Paris.”—Quarterly Journal of the Geological Society 
of London, vol, xii, p, 204, pl. 3 (1856), 1 am glad to find, carefully reperusing this Memoir, that it affords 
no ground for the difference alleged to exist between myself and tho accomplished writer of the following 
remarks:—* Je ne puis partager l’opinion de M, Owen relativement aux rapports qui existent entre le Gastornis 
et les oiseaux du groupe des Rallides.”—Alphonse M.-Edwards, Recherches Anatomiques and Paldontologiques 
pour servir 4 Histoire des Oiseaux Fossiles de la France, 4to, p. 172. 
7 Op, cit. p, 167. * Op, cit, pl. 29, figs, 3 & 4. 
