72 OSTEOLOGY [Parr II. 
The upper mandible, viewed from above, presents on each side a shallow excavation 
extending from the core to the base of the maxilla ; the upper edge of the ramus of the lower 
jaw forms the chord of the concavity, which lodges the curved tubular nostril. This charac- 
teristic appearance is owing to the great compression of the lateral beams of the mandibular 
apparatus towards each other, by which they are, as it were, forced almost into contact 
beneath the upper stem; their height being thus increased at the expense of their breadth ; 
while their oblique bases diverge towards their upper or terminal angles, and each beam 
resumes, so to speak, its original thickness. 
The length of the skull, measured from the upper border of the foramen magnum 
to the apex of the mandible, is 8 inches 23 lines; its breadth, a little in front of the 
post-orbital process, is 3 inches 85 lines; the greatest elevation of the cranium is 2 inches 
5 lines. The extreme length of the lower jaw is 7 inches 9 lines, and its span 2 inches 
10 lines. 
On a more minute examination, the skull of the Dodo will be found to present the 
typical characters of that segment in the Columbidé, which are :— 
I. A feebly uncinated wpper core; a character which at once distinguishes the Dodo 
from the Vulturide on the one hand, and Cathartes on the other. 
II. An external nasal fissure extending from the base of the core, as far as, or beyond 
the resilient hinge formed by the upper beam of the mandibular apparatus at its junction with 
the cranium ; in all raptorial birds, the major part of the body of the nasal is placed in front 
of that line; while in Pigeons the body is abbreviated and rises high on the frontal slope, the 
divergence of its limbs exposing to view, in certain genera, the turbinated ala of the ethmoid. 
The rasorial genus Pterocles presents a similar character; hence it is not distinctive of the 
Columbidee. 
In the Vulturidz, the nasal scale is ossified to support the horny cere, and the nostril 
opens anteriorly by a narrow vertical orifice; while in the Dodo, the elongated lanceolate 
nasal fissure extends to the foot of the frontal protuberance. 
III. The elevation of the base of the maxillary bone to meet the expanded foot of the 
abbreviated ecto-nasal limb, and the obliquity of the zygoma, which must descend as it 
retrogrades from the junction of these bones, to the level of the inferior articular surface of the 
os quadratum. The maxillary in Pigeons is subpyramidal with a triangular section ; the apex 
extending forwards, like a splint, on the inner side of the lateral process of the premaxillary ; 
the external surface slopes obliquely upwards and outwards from the palatine aspect, and is 
more or less tumid; the angle which it forms with the inner concave facet is united to the 
pyramidal foot of the ecto-nasal limb behind, the termination of the lateral premaxillary 
process bemg wedged between them anteriorly. The ecto-nasal limb passes upwards and 
backwards from the upper angle of the base of the maxilla; the inner edge is prolonged into 
the antral plate, and is separated by a groove, on the floor of which occurs the pneumatic 
foramen, from the terminal border of the external surface, which ascends obliquely backwards, 
its upper angle passing into the slender zygoma. 
