78 
MR. W. K. PARKER ON THE STRUCTURE AND 
The structures seen under the tegmen (fig. 9) are the incus, malleus, and stapes 
(see also fig. 5), where they are shown as detached, and from the outside, the stapes 
dislocated from the incus. The malleus has a large manubrium ( m.ml .), with a strong 
elbow (posterior angular process, p.ag.), turned towards the membrana tympani. The 
whole of the process is set on to the head of the malleus at more than a right angle ; 
but, from the round bulbous fore part of the head, the processus gracilis ( p.gr .) is con¬ 
tinued straight forwards; that part is a long spatula, dilating forwards as it runs 
towards the Glaserian fissure. It has been much larger, 1 have no doubt (see in the 
Unau, Plate 9) ; afterwards it is absorbed up to its root (see Doran, plate 64, fig. 13). 
The mutual sinuosities of the two bones at their junction give the hinge of the 
malleus with the incus an angular appearance (fig. 5, i., ml.) ; a good face of cartilage 
remains at this part. The top of the short process and the disk of the long process of 
the incus (s.c.L, l.c.i.), are still unossified; the long process is well elbowed before it 
turns inwards, near its dilated end; this part is quite normally Mammalian. 
But the stapes (st. ) is not normal; the hole is absent; this element is a short flat 
“columella,” with apex and base still unossified; afterwards (Doran, op., cit.) a 
feeble vertical fossa forms along the shaft where a groove is shown. Now and then this 
bone becomes almost a “ stapes.” Here we are on the level, or height, so to speak, of 
the Metatheria. There is a small interhyal ( i.hy.) on the neck of the stapes. 
Returning to the large vertical section (fig. 7) and its partial counterpart (fig. 8) we 
see that the nasal labyrinth is quite normal and not badly developed ; the nasal, 
inferior, middle, and upper turbinals (fig. 8, n.tb., i.tb., m.tb., u.tb.) are all well formed, 
although the complication of the last two regions—parts of the true olfactory region 
—is not great; these coils of cartilage are quite unossified, so that my largest specimen 
must have been very young. 
In the main section (fig. 7) the roof bones ( n.,f., p.) are shown to be rather solid ; 
the nasals overlap the frontals, which cover the olfactory region by their fore part (see 
also fig. 2). But the orbital region of the frontal, and the temporal region of the 
parietal bones are developed downwards in an almost Ophidian manner, so that a little 
further ingrowth of the former would have given us a perfect frontal cincture—a 
state of things not absent from some of the high Eutheria. The parietal comes down 
and lies on the low alisphenoid ( al.s.) by a broad emarginate process, behind which a 
small oval intercranial tract of the squamosal (sq.) is seen ; as small as in the average 
Bird. The right jointed palatine beam is seen reaching from the back of the snout to 
the front of the foramen magnum, the series forming this many-pieced “ balk ” of 
bones is as follows : the premaxillary, maxillary, palatine, and pterygoid (px ., mx., pa., 
pa. read pg.) ; these form the floor of a continuous canal, which opens freely into that 
of the other side, all along. 
There is a small bone, the front paired vomer (figs. 7 and 10, v'.), right and left 
over the fore part of the double channel—the naso-palatine canal, and behind it a 
grooved bone, the vomer (v.), as long as the palatine plate of the maxillary; right 
