240 MR. W. K. PARKER ON THE STRUTCURE AND 
stylo-mastoid foramen (VIT.). That tegminal edge of the squamosal runs inwards as 
a vaulted roof to the cavum tympani, nearly half-way across. Inside, the cochlea fills 
up the space behind, but, in front, the retral growth of the alisphenoid (q/.s.) fills in 
three-fifths of the remaining space and sends backwards a spur to the cochlea, which 
divides the rest into a large outer, and a small inner, fenestra, covered only by the 
dura mater. This structure is Soricine, but it is also Marsupial; it is much more 
Marsupial in character than that which is seen in the Shrew. 
The suture between the squamosal and alisphenoid is nearly lost, but the former 
sends downwards a thin lamina of bone which shows where they have joined ; close 
inside the glenoid cartilage the squamosal is bent inwards, and appears as a convexity 
in the fore part of the tegmen. The (Marsupial) alisphenoidal wing (a/.s.) is extremely 
thin, and coils over backwards as a sharp selvedge. The basisphenoidal wings (¢.b.s.) 
are much deeper and more hollow than they appear at first sight, in the basal view 
(fig. 1). 
Behind (fig. 1), the relatively spacious tympanie chamber is partly closed in, and 
filled up, by the remarkable auditory capsule, which is thoroughly ossified, and retains 
its distinctness all round its border ; it is, however, not so loosely set in the skull as 
in the native Shrew, or as in our native Bat (Pipistrelle). 
The tilting of the auditory capsules is shown in the side view (fig. 3), and the 
horizontal and posterior canals (h.8.c., p.s.c.), are seen in that and also in the posterior 
view (fig. 5), and in the lower view (fig. 1). There is no prootic wall-plate in front 
of the smoothly convex part, through the walls of which these canals are seen. 
The facial nerve (VII.) is seen emerging close behind a small, separate epihyal bone 
(e.hy.); inside these parts the fenestrze of the capsule lie out of sight. Inside and in 
front of the posterior canal, and of that part of the labyrinth into which it opens, 
there is a convex oval enlargement of the postero-inferior face of the cochlea (chi.), 
hiding its fenestra, which opens in front of, and above, the oval swelling, and exter- 
nally forms the front margin of the foramen lacerum posterius ([X., X.). The basal 
and lateral upper elements of the occipital arch (b.0., e.0.) are fused together; the basi- 
occipital is short axially, and the lateral parts each form a small paroccipital process 
( p.oc.) close outside the large pyriform condyles (0c.c.). The supraoccipital (s.0.) 1s a 
large shield of bone, well in the back of the skull, and not lying over, as a hind 
teymen, as in the Mole and Shrew. It is quite distinct from the auditory capsules, 
and is fused with the lateral elements of the arch (e.0.); lying over a very large 
foramen magnum, round, but with a recess in front, it is a relatively great shield of 
bone, with a large circular convexity in the middle, separated by two oblique fossve 
from a subcrescentic convexity, right and left. 
The supratemporal pieces (s.f.) impinge upon the bone over each fossa; it arches 
very accurately over each auditory capsule above and outside, where it has ankylosed 
with the exoccipitals (e.0.). The whole of the upper margin of the supraoccipital is 
