94 OSTEOLOGY [Parr II. 
subsiding in front towards the maxillary, it is rounded off into the obtuse apex behind; the posterior 1s 
shorter, subconcave, and terminates at the anterior part of the sphenoidal plate ; its inner surface is concave 
in the antero-posterior diameter, but subconvex vertically ; a groove, corresponding to the crest externally, 
indicates the junction of its concavity with that of the nasal process. The narrow, elliptical, posterior 
nasal fissure is, anteriorly, prolonged into the slit between the lateral mandibular beams; in the dried state 
of the soft parts, the anterior angle of the posterior nares was two inches two lines and a half anterior to 
the point where the palatines meet on the rostrum. 
An oblique line, directed forwards and inwards from the convexity of the crest to its inner margin 
anterior to the subsidence of the palatine process, defines the fossa between the crest and the palatine 
process, which gives attachment to the fleshy fibres of the internal pterygoid; the depressed tract on 
the anterior part of the crest, gives attachment to the tendon of that muscle; its fleshy fibres also arise 
from the fossa between the nasal process and crest, which is concave vertically and convex horizontally ; 
it is prolonged posteriorly into a deep rough depression on the outer surface of the sphenoidal plate, at the 
bottom of which is the pneumatic aperture. The palatine bone is almost destitute of pneumaticity ; the 
length of its free portion is two inches and a half. 
The pterygoid bone, one inch two lines and a half long, is curved like the human clavicle, convex 
externally in front, and concave behind, and formed by a thin narrow band, twisted on itself and expanded 
at both extremities. The outer edge is thick and rounded behind; in front it becomes thinner, being 
flattened inwards, so as to encroach on the upper aspect, which thus exhibits an elongated triangular tract 
passing into the base of the inner extremity. The imner edge presents, on the left side, an angular 
projection in the centre, the rudiment of the sphenoidal articular surface ; anterior to which it is flattened 
outwards, extending to the apex of the inner facet ; the inferior surface is thus grooved in its two anterior 
thirds. On the upper aspect, a bidentate crest extends from the outer extremity obliquely wards, and 
subsides towards the centre, bounding internally a lanceolate space. The inner extremity is triangular ; 
the surface gliding on the sphenoid is slightly convex, and its anterior edge is united by ligament to the 
palatine bone; the compressed, oval posterior extremity is impressed by a narrow deep concavity for arti- 
culation with the tympanic. The pterygoid is destitute of pneumaticity. 
The ¢ympanic bone, viewed from behind, is X shaped ; the lower segment bemg most extended trans- 
versely. The internal limb above is bent backwards, and supports an oblong articular tubercle, forming 
the posterior condyle, around its base are several foramma ; the anterior is larger and covered by a trian- 
gular synovial surface, the apex behind its imner angle extends into a curved linear strip connecting them ; 
the ligamentous groove is most distinct anteriorly and externally in both. A deep circular concavity, with 
a reticulate floor pierced by numerous pneumatic apertures, separates them posteriorly. A slight ridge, 
leading from the external condyle to an inflected notch at the centre of the outer concave edge, indicates 
the attachment of the membrana tympani. The inner margin is more defined, less curved, and exhibits a 
semi-obovate outline. Viewed externally, the figure is cruciform ; the lower and outer angle projecting, 
and impressed by a deep pit for the extremity of the zygoma. The orbital process, corresponding to the 
upper and inner limb, is formed by a thin, curved, triangular plate ; the apex is broadly truncated, inflated 
and slightly deflected outwards above ; the outer surface is convex and pitted for the external pterygoid 
muscle, except for a narrow tract beneath the apex, extending backwards along its upper margin, which 
runs outwards to the anterior condyle; its inferior angle is bent imwards and expanded into a narrow 
pterygoid convexity, at the apex of which is a pneumatic foramen. The inferior moiety of the external 
aspect is smooth, polished, and convex across the projecting angle. 
