Cu. I.] OF THE DODO. 95 
The inner surface presents a tripartite fossa, deepest inferiorly, rough throughout; and obliterated 
towards the extremity of its anterior angle by the expansion of the diploé of the orbital process, which is 
subtranslucent : it gives insertion to the /evator muscle. A triangular flattened surface, its base extending 
between the condyles, separates the upper limb from a slight concavity, which impresses the external 
surface above, and indents the orbital process. 
The mandibular extremity is compressed in the antero-posterior diameter; widest externally, and 
constricted in the centre. In its internal half, it forms a narrow transversely extended and downwardly 
projecting crest; the outer segment is flattened vertically into a quadrate plate, and twisted from before 
backwards on its axis. A broad groove directed obliquely forwards renders its inner moiety subconcave, 
and hollows out the inner tubercle externally. Articular cartilage covers the backwardly sloping inferior 
surface of the outer condyle, dips into the groove, and expands over the thick rounded edge of the inner 
one, which presents a large reticulated pneumatic foramen, and over its anterior surface, at the external 
angle of which it is narrowest. The greatest diagonal is one inch four lines and a half, and the least one 
inch three lmes; the width of the upper extremity is eight lines and a half, and that of the lower one inch; 
it is three lmes broad where most constricted. The orbital process is seven lines long; from its apex, 
which is three lines and a half wide, to the zygomatic angle, is one inch and three lines. The width of the 
outer mandibular condyle is five lines, of the inner two lines and a half; the length of the former is four 
lines ; that of the latter, five lines and a half. 
The rami of the dower jaw, six inches in length, measured along the lower border, are separated by an 
interval of two inches seven lines between their angles, but unite at a short, acute symphysis, which ascends 
at an angle of about 45° with the lower margin. ach ramus is thin and curved, the convexity mounting, 
external to the palatine wedge, into the angle between the inferior margin of the maxilla and the zygoma. 
The greatest height is at the centre, and amounts to one inch; it diminishes shghtly towards each extremity. 
The upper edge is sigmoidal, convex behind, but concave in front; the profile line of the sharp upper edge 
of the core ascending very gradually as it advances, and then curving rapidly downwards to the mesial line 
of the symphysis, which is broadly emarginate anteriorly, concave above and subangularly rounded below; 
its convexity is adapted to the concavity of the edge of the upper core, while the decurved apex of the latter 
is fitted to its emargination. The lower concave edge is rendered slightly convex towards the centre of the 
posterior moiety, by the projection downwards of the dentary and angular elements. The dentary piece, 
exclusive of the core, is subequal in length to the posterior segment of the ramus; which is formed by the 
coalescence of the surangular, angular, and articular elements; the opercular remains distinct, perhaps, to 
a late period of life. 
The dentary bifurcates posteriorly ; the upper limb is slit vertically, to receive the surangular, whose 
free portion, unoverlapped by the long, narrow imner dentary plate, advances halfway to the core; the 
suture between it and the short deeper outer lamina, is seen along the upper edge. The lower limb extends 
backwards, contracting, along the outer surface of the angular ; whose thick lower border, thinning anteriorly, 
passes forwards, between it and the opercular, as far as the centre of the inferior edge of the ramus. The 
irregularly lanceolate opercular, partly covers the angular and dentary pieces, and rises to close the com- 
pressed space (dental canal) containing nerves and vessels; its posterior extremity extends along the inner 
surface of the angular, beneath the inflated portion of the articular; its superior border comes in contact 
with the immer and upper dentary lamina; anteriorly it terminates one inch behind the lower angle of 
the symphysis, its inferior edge diverging from that of the dentary; its length is about three inches, and 
its greatest depth six lines. The opercular begins to coalesce with the dentary, along the anterior part of 
2c 
