MEMOIR 
ON THE 
MODIFICATIONS OF THE SKULL 
IN THE 
GENUS DINORNIS. 
IN the Memoir on the skeleton of Dinornis élephantopus, the skull is briefly noticed 
(p. 253). Subsequent acquisitions of specimens of that part, in some respects more 
complete, enable me to better appreciate its specific characters and to bring them out 
by comparisons with those of the skull of Dinornis robustus, described pp. 151-169. 
L also avail myself of these grounds to determine and elucidate the cranial characters 
of some other species of Dinornis, as well as those of a seemingly dinornithoid gigantic 
bird which, like Gastornis parisiensis, existed in our own part of Europe at a remote 
tertiary period, 
Skull of Dinornis elephantopus. (Plate LXXVIL.) 
The cranium of Dinornis elephantopus equals in length that of D. robustus', but is 
inferior in breadth and more convex both longitudinally and transversely, especially the 
latter, at the interorbital region (fig. 3,11). The entire skull of D. elephantopus is 
shorter than that of D. robustus, by reason of the relatively shorter premaxillary and 
mandibular bones. 
The occipital condyle (Pl. LXXVII. figs. 2, 4,1) is a hemispheroid with a small pro- 
portion truncate above, from the middle of which surface a groove extends to the 
centre; its breadth is 43 lines, its vertical diameter 4 lines. 
The occipital foramen is in one skull subcircular, in others shield-shaped, as in the 
second specimen of D. robustus (Pl. LV. fig. 2). The lower transverse superoccipital 
ridge (Pl. LX XVII. fig. 2,2), which overhangs the foramen, subsides upon the exoc- 
cipitals sooner than in D. robustus. The basioccipital descends proportionally lower to 
its bimammillate union (ib. figs. 2, 4, 1’) with the basisphenoid. There is one small precon- 
‘ Measured from the superoccipital protuberance to the premaxillary depression on the nasals; comp, 
Pl. LXXVIL. fig. 1 with Pl. LXTIV. fig. 1, 

