262 MR. W. K. PARKER ON THE STRUCTURE AND 
the basisphenoid the parasphenoid (pa.s.) is seen. Between the alisphenoid and the 
auditory capsule there is a large semi-oval space filled in by the squamosal (sq.), 
which is hollow inside, the concavity being a continuation of that formed by the 
parietal, Above the hind corner of the squamosal and over the upper and front 
part of the auditory capsule the parietal forms a thick and rough rudiment of the 
“tentorium cerebelli.” Under that rafter-like bar the squamosal (sq.) shows a roughly 
triangular inner face, which hes outside the arch of the anterior canal (a.s.c.), and 
supports the lower half of the fore edge of the supraoccipital (s.o.) ; the re-appearance 
of the squamosal inside is due to its great height, especially behind. The auditory 
capsule is subvertical in position, and in this view shows the great arch over the 
recessus flocculi, the multiperforate meatus internus (VIII), with the bridge over 
the facial nerve (VII.) a thickening where the posterior canal (p.s.c.) begins, and a 
somewhat notched edge where the 9th and 10th nerves (IX., X.) emerge. The basi- 
occipital (b.0.) is thick in front and thin behind; it is one-third longer than the basi- 
sphenoid (b.s.). By an obtuse angle it wedges in between the capsule and the lateral 
oceipital (e.0.), which is a broad and high bone, having a large oblique hole for the 
hypoglossal nerve (XII.) not well seen in this aspect, and a small posterior condyloid 
foramen (p.c.f.). The supraoccipital (s.o.) and interparietal (¢.p.) now form one large 
shield-shaped bone, finishing the postero-superior face of the skull, and articulating 
with the parietals and exoccipitals, but kept apart from the petromastoid by the 
large post-temporal part of the squamosal, 
In the side view of the smaller young of G. philippensis (Plate 38, fig. 4) the snout 
with its valvular opening (a/.7., ev.) is seen in front, and the top of both the orbito- 
sphenoid and alisphenoid (o.s., a/.s.) laterally, in the fundus and back of the orbit. 
Here it is seen that the alisphenoid reaches much higher than the inner view (fig. 7) 
would seem to show. The occipital condyle (oc.c.) is seen in both these views, and 
some part of the mastoid (op.), the exoccipital (e.0.), and the supraoccipital (s.0.). 
In the basal aspect (Plate 37, fig. 6) several important parts are displayed, not 
covered by the superficial bones. In front, the alinasal region shows with great dis- 
tinctness the origin of the recurrent cartilages (rc.c.); the external nostrils (e.n.) 
are more terminal, as in Marsupials, than in the other kind. The presphenoid, basi- 
sphenoid, and basioccipital (p.s., b.s., b.o.) are displayed, with the parasphenoid (pa.s.) 
under the middle piece; the basisphenoids and basioccipitals are much wider in this 
space than in the other. The alee are not much displayed, and the alisphenoid is 
largely overlapped by the squamosal. The small mastoid process (op.), with the stylo- 
mastoid foramen and epihyal in front of it, and the exoccipital void of any distinct 
paroccipital process, are also well seen. The subcircular foramen magnum ( fm.) is 
bordered by the large projecting semioval condyles (o0c.c.), and, behind, the supra- 
occipital (s.0.) can be seen finishing the great doorway. 
Part of another lower view in the larger young (fig. 8.) shows the foramen 
ovale (V*.), the channel for the facial nerve (VII.), the fenestrae—fenestra ovalis 
