202 
HR. W. K. PARKER ON THE STRUCTURE AND 
(f) are much shorter than the nasals and about twice as broad on their upper face; 
that face is only one-third as large as that of the parietals, which are very large, have 
a strongly marked umbo, the primary centre, and have a small diamond-shaped 
fontanelle between them and the frontals in which the coronal, sagittal, and frontal 
sutures meet. These bones elbow outwards, strongly, over the temporal region, and lie 
well over the squamosals ( sq .), which are scarcely visible in this aspect. Behind, the 
parietals are largely suppressed, a space (fontanelle) existing there almost equal to a 
whole parietal; this is beginning to be filled in, behind, by a bow-shaped band of bone, 
the interparietal {ip), which forms a transversely-long beading to the well ossified 
and extensive supraoccipital bone (s.o.). 
The side view (Plate 31, fig. 10) shows the form and relations of the parts just 
described, and many other things besides. The snout ( al.ne.n.) is largely arched, 
and reaches half-way to the middle of the badly-defined orbit. Under the long thin 
nasals (n. ) the premax diaries and maxillaries (px., mx.) are seen to form large thin- 
walled troughs, for the huge tooth-pulps ; through which the sharp, red cusps shine, 
ready to cut the gums. 
In front of the orbit there is a process of the maxillary which is beginning to form 
the nerve channel, but no separate malar bone ; in an emargination of the maxil¬ 
lary, above, a small lachrymal, with its canal (l., lc), is seen. 
The roof plate of the frontal (f) becomes convex at its edge, and then dips suddenly 
to form the thin, vertical orbital plate, under which the small, but bulging, alisphenoid 
(fig. 11, cd.s.) can be seen ; the orbitosphenoid is hidden by it, and by the frontal, in 
this aspect. The lateral extent of the frontal is only half that of the parietal, wdiich 
is a wall, in this case as much as in our own skull. It lies over the frontal somewhat 
at its antero-inferior angle, close behind the coronoid process of the lower jaw (c.p). 
Large as is the parietal, it has two gi’eat deficiencies or emarginations, one above, 
already described, and one along the hinder half of its lower margin. In this aspect 
we see the squamosal (sq.) in its whole extent; and much as this bone is modified by 
the dwarfing of the skull, generally, it is normally Mammalian. It lies quite down at 
the lower edge of the skull, rising somewhat wdiere it forms an abortive zygomatic 
process, in front of the condyloid facet (< cdp .). The first two-thirds of the upper edge 
is concave where it fits over the lower edge of the parietal, and the last third is 
emarginate when it overlaps the prootic plate ( pr.o'.). Behind, it intendigitates with 
that plate in some degree. The postero-inferior margin is convex, for a short extent, 
and then the lower edge looks quite straight, but is only partially seen, being curved 
inwards (Plate 29, fig. 2, sq.). Under the squamosal, the tympanic ( a.ty .) is just seen, 
and under the face the characteristic mandible. This latter structure for its fore 
two-tliirds is a thin tooth-trough, behind which the large, elegant coronoid process 
(c.p.) ascends, vertically ; its fore edge is two-thirds as long as the dentary part of the 
ramus. The condyloid process (cd.p), on the other hand, is very short; looks down¬ 
wards and backwards, covered wfith its cartilaginous coat. The angular process (agp) 
