144 PROFESSOR OWEN ON THE GENUS DINORNIS. 
being the widest, as in Dinornis struthoides (Trans. Zool. Soc. vol. iii. pl. 38. figs. 1, 3); 
the occipital condyle (1) is less pedunculate; the temporal fosse (fig. 1,7) are wider, 
with a different contour; and the prosencephalic chamber is more prominent on the 
upper surface of the cranium; the smooth tract between the temporal and occipital 
muscular fosse is also narrower in Dinornis ingens than in D. struthoides. The mastoid 
(Pl. XV. fig. 1,8) is produced as a slender process about five lines below the masto- 
tympanic articulation; the premastoid ridge (ib. 8’) seems more definite than in D. stru- 
thoides. ‘The postfrontal process (12) is relatively longer than in Dinornis robustus'; the 
zygomatic arch (26 27) sends upward a more definite process toward the postfrontal. 
The rostrum (22 32) accords with the type of that in Dinornis robustus (Zool. Trans. 
vol. v. pl. 4. fig. 1), but is rather narrower and less obtuse. 
The figures, of the natural size, in Pl. XV., in which each bone bears its symbolic 
number, with similar figures in the present and former Memoirs of other species of 
Dinornis, give grounds of comparison which preclude the necessity of further verbal 
notice of details. One notes with interest that a species with comparatively long and 
slender limbs in the present wingless genus has a more lengthened beak (e. g. Dinornis 
ingens) than Dinornis crassus, and that the diploé of the cranial walls is less thick, 
showing the more than usually domed character of the cranium” in this broad and flat- 
headed group of extinct birds. The range in the length of the rostral part of the pre- 
maxillary exemplified by Dinornis crassus and Dinornis ingens, indicates a ground of 
derivative variety in which the existing Apteryx exemplifies a maximized degree. But, 
unless this gain was sudden in the dwarf species, the intermediate steps should be 
numerous, and have not yet been observed. 
In the ‘ Bericht tiber einen fast vollstindigen Schidel von Palapteryx,’ Dr. Gustav 
Jaeger compares his specimen with the several figures of the skulls of New-Zealand 
extinct wingless birds given in the 3rd volume of the ‘Transactions’ of the London 
Zoological Society, pls. 38, 39, 52, 55, 55, but appears not to have been cognizant of 
the Memoir in the 4th volume (p. 205), in which not only is the most complete skull 
of a Moa described and figured which had, at that date (1850), been obtained, but 
also one belonging to the same species as that to which Dr. Jaeger is finally led to refer 
the subject of his description. (See “ Erklirung der Tafel xxv., Schiidel von Palapterya 
ingens, Ow.,” at the close of the Memoir.) 
The chief aim of the comparisons of the accomplished Director der Wiener 
Thiergartens is to show that his specimen exemplifies the generic characters of Pala- 
pteryx by contrast with those of the skull referred, erroneously, by me to Dinornis 
casuarinus, in my third Memoir (1848), p. 445, pl. 52. vol. iii. Trans. Zool. Soc. That 
* In the specimen figured in Vol. IV. (1850) the postfrontals were broken and their abrupt down-bending 
not sufficiently allowed for (p. 60). 
* This character of the skull of Dinornis ingens is somewhat exaggerated in Dr. Gustay Jaeger’s figure 
(Taf. xxv. op. cit.), through the view in fig. 1 not being a direct profile but looking obliquely on the calyarium. 
