The mandible thus presents a subtriangular surface, of greater or less extent, and more
or less tumid, which is covered by the palatal membrane; it is continued backwards by
the external fibrous wall of the subocular cell, extending from the root of the zygoma to the
free outer margin of the palatine crest. The surfaces of opposite sides, separated mesially by
the posterior nares, form a wedge subsiding anteriorly towards the nasal orifice, and descending
between the rami of the lower jaw, which are so curved that their convexity mounts into
the obtuse angle formed between the zygoma, and the lower margin of the lateral facet of the
maxilla; which is indicated in the Dodo by the upper caruncular ridge, separating the palatal
mucous membrane from the cere, and extending forwards to the lower angle of the nostril.
In those grallatorial and aquatic buds, as the Ibis, Spoonbill, and Albatross, which have a
similar arrangement, the margin of the upper mandible overhangs that of the lower; and in
the Albatross the posterior part of the dentary bone is lodged in a deep groove, between the
palatine wedge and the acute margin of the mandible.
IV. The absence of an ossified vomer separating the posterior nares; this is also generally
deficient in the Gallinas; in the Vulturida; it exists in the form of a narrow lanceolate plate,
but is wanting in Cathartes.
V. The septum narium is generally membranous in Pigeons ; it exhibits however traces
of ossification at its attachment above, in the Calamus nicobarica, and Lopholamus anfarcticus;
in the Vulturidse it is wholly ossified, a small perforation only existing in certain species; in
Cathartes it exists, although reduced in length, by the removal of its anterior part in the
formation of the common nasal vestibule. In the Dodo it is completely membranous.
VI. The form of the palatine bone in Pigeons is characteristic, and differs from that in the
Rasores, in the presence of the horizontal plate or crest, which affords an increased surface
for the origin of the internal pterygoid muscle; and of the descending palatal process, which
supports the fold of mucous membrane forming the lateral boundary of the posterior nares.
In the Vulturida;, the crest is much broader, indicating the greater strength of the muscle
arising from it; the sphenoidal plate is narrower from the unexpanded condition of the
rostrum; the nasal process is much contracted longitudinally, whereas in Pigeons it extends
forwards along the inner margin of the palatine stem, to near its attachment; the palatine
process is less elongated, and the inflected portion of it, in Pigeons, is entirely absent; the
palatine stein is straight in Vultures, arched with the concavity inwards in Pigeons. In
Cathartes the stem is also curved; the nasal process is more extended than in Vultures, but
less elevated than in Pigeons; the crest however indicates the raptorial character by its
great breadth.
We shall afterwards see how the form of this bone, in the Dodo, is modified by the
compression of the mandible and the abbreviation of the rostrum, without departing from
the Columbine type.
VII. The shape of the inferior articular surface of the tympanic bone, although it varies
in different genera of the Cohunbida?, is distinguished from that in the Vulturida?, by the
The upper mandible, viewed from above, presents on each side a shallow excavation
extending from the core to the base of the maxilla j the upper edge of the ramus of the lower
jaw forms the chord of the concavity, which lodges the curved tubular nostril. This characteristic
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 2 j lines; its breadth, a little in front of the
post-orbital process, is 3 inches 8^ 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 Columbidaa, which a r e :—
I. A feebly uncinated upper core; a character which at once distinguishes the Dodo
from the Vulturida; 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
Columbidaj.
In the Vulturida3, 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.
I I I . 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 being 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.