DEVELOPMENT OP THE SKULL IN THE MAMMALIA. 
85 
middle they diverge rapidly, so do the parietals {p.) behind them, but they are 
separated by a much wider space, almost equal to their own width. Hence the 
fontanelle (fo.) is very large, has a narrow median limb in front, and a postorbital, and 
a supraoccipital pair of transverse limbs ; above, the median part is, over the vertex, 
dilated as a wide lozenge-shaped space. 
But these things are seen also in an instructive manner in the side view (fig. 3). 
The narrowish snout is but little turned downwards, it very suddenly passes from its 
short aliseptal region into the swelling ethmoids ( al.e .). In front ( al.e.) the alinasals 
form a crescentic portico over the sub-inferior nostrils ( e.n .). Behind these parts—the 
snout, proper—the swelling caused by the inferior turbinal at the side, arches upwards 
and outwards from the semicylindrical upper tract ( al.sp.), which contains the nasal 
turbinal; behind this is the bulbous olfa.ctory region {al.e.), the narrow end of which 
( m.tb .) can be seen in the fore part of the orbit, below. The small forked nasal (n.) is 
seen to be a long way behind the external nostril {e.n.), and a good distance from the 
ascending toothed edge of the maxillary “scale” {rnx.), in front of which is the 
narrow, oblique, ascending part of the premaxillary ( px .). 
The frontal {/.) is moulding itself upon the orbital recess, and has a neat, super¬ 
orbital edge ; the bone is pinched in in front of that part. The toothed edges of 
these osseous scales—the frontals and parietals—nearly touch in the postorbital 
region. Under the inturned part of the frontal, the cartilage {o.s.') lines the orbit, 
and just shows itself beyond, at the edge of the temporal region. Below, in the 
postero-inferior recess of the orbit, the optic nerve (II.) can be seen emerging through 
its ring of cartilage ( o.s .); it rests upon the thickish palatine bone {'pa.). A large 
lozenge-shaped space is seen between the frontal, parietal, and squamosal {/., p., sq.); 
the latter hardly reaches the parietal in the temporal region, and is altogether a very 
jagged plate. Its jugal process runs outwards and forwards and shows its small 
pyriform glenoid facet ( gl.f) ; its posterior part runs, splintery, over the face of the 
auditory capsule, hiding the ampullae of the anterior and horizontal canals {a.-s.c., 
h.s.c.). But the hinder part of the latter, and the junction of the anterior and 
posterior canals (p.s.c.) —the latter displaying its ampulla—all these are clearly seen in 
this view, and also that the capsule itself is not much tilted, at present. The cochlea 
{chi.), with its coils, and the pterygoid {pg.) with its cartilaginous cap, are seen under 
the squamosal. Behind the swelling capsule, the large occipital arch shows an 
unusual amount of its surface in this aspect; it is a short, wide tube. 
Above, the bony supraoccipital {s.o.) is partly seen ; laterally, this broad arch shows 
its sinuous edge behind the parietal, coming down to unite with the capsule above the 
junction of the two upper canals {a.s.c., p.s.c.). The two parts of cartilage are con¬ 
fluent along the hind margin of the capsule, and here the exoccipital region {e.o.) is 
thickened obliquely, upwards and backwards, into a low paroccipital ridge; the 
condyle {oc.c.) is here seen in its upper part. 
The incus (i.) is seen just peeping from under the postero-inferior corner of the 
