DEVELOPMENT OF THE SKULL IN THE MAMMALIA. 
99 
pital (e.o.), and the thickened rim formed by it to the foramen magnum. The bony and 
cartilaginous parts of the supraoccipital are just seen, and also the condyle ( oc.c .), below. 
The lower jaw (Plate 12, figs. 8, 10, 11, d.) is a mere sinuous bar of bone, capped 
at its posterior-superior part by a condyloid facet, in front of which a slight elevation 
is all that appears of the coronoid process ( cr.p .), and under which there is no angular 
process, whatever. The symphysial face is oval and rough, and the dentary edge is 
sharp and roughly dentated; between that part and the aborted coronoid process 
the upper outline sinks into a gentle curve, answering to the convex outline below. 
Inside the hind part of the ramus the bone is scooped away for Meckel’s cartilage 
and the burrowing nerve (V 3 .), and vessels. The secondary mandible is now one- 
fourth larger than the primary, for the fore part of Meckel’s cartilage (mk.) is lost, 
and the rest is a sinuous rod partly in front of and partly behind the persistent 
ramus. This sub-proximal part of the primary rod is only attached to the ramus in 
front of the bony processus gracilis, behind, by ligamentous fibres. The proximal 
part, now the ossified malleus (ml.), is quite normal, with the curved manubrium (m.ml.) 
and is equal to the processus gracilis. The incus (i.) is now quite ossified, and its 
short crus is relatively larger. The stapes (figs. 11 and 12, st.) is still merely a 
columella, with a ragged hinder margin to its flat rugous stem, and a small inter- 
hyal in the tendon of the stapedius muscle ( i.ky ., st.m.). 
In this species, at this stage, there is a small second upper ceratohyal (fig. 13, c.hy.), 
and the rest of the bar (c.hy.) is ossified in its middle part; the basal bar, with its 
horns ( b.h.br ., t.hy.) is still unossified; its shape has not changed since the last stage. 
The occipital rigion, as seen from behind (Plate 12, fig. 9), shows great progress in 
ossification since the last stage (fig. 2) ; and in this more finished ovoid the superficial 
bones (sq., p.) come more into view in this aspect. The notch above the foramen 
magnum ( s.o.n .) is as large here, as in the smallest specimen (PJate 11, fig. 4), the lateral 
cartilaginous tracts failing here for some distance. The three bones that are forming 
this face of the skull ( s.o ., e.o.) are still separated by a considerable amount of 
cartilage. The basal bone ( b.o .) just comes into view. The paroccipital margin 
(p.oc.) of the lateral bones (e.o.) forms a definite ridge on each side, separated from the 
condyle (oc.c.) by a gentle vacuity. 
Fourth Stage.—Shall of adult Pangolin. (Manis-? sp.). 
Some things worthy of notice appear in the skull as it becomes adult. In the 
lower view of the adult skull, with the hinder part removed (Plate 13, fig. 2), we see 
the strength of the roof-bones, and that they are strongly marked, inside, by the 
brain; these digitcd impressions of the inner table are very clear. So also is the 
bony tentorium (t.tm.) strong, and strongly fixed to the supraoccipital (s.o.) as its 
key-stone; outside that ingrowth the great tympanic recess in the squamosal (sq.) is 
laid bare. In front of this the postglenoid pneumatic foramen (pn.f) is seen, and in 
