48 MR. W. K. PARKER ON THE STRUCTURE AND 
plate of the palatines is as arrested as in the very open palate of a Rabbit, or the 
most closed (‘desmognathous”) palate seen in Birds, namely, in Podargus (see Trans. 
Linn. Soe., ser. 2, Zool., vol. 1, Tab. 23, figs 6-8).* 
In the distance, the large orbital plates of the frontal are seen, and laterally, on the 
level of the palate, the jugals and squamosals (j., sq.) ; these lateral parts have a pecu- 
liar independence of each other. Such is not seen again until we are down among the 
Lizards and Serpents. Here the large jugal (j.) is articulated to the maxillary in 
front, but has its bifurcated hind part free. Answering to this structure, the zygomatic 
process of the squamosal (sq.) is aborted, and the large crescentic glenoid saddle (g/.f-) 
lies between two thick ridges of bone, its concavity looking forwards. These ridges 
meet behind the facet as a low, arched postglenoid tract, and then the rest of the 
bone, as seen in this aspect, runs outside the tegmen tympani (¢.ty.), largely helping 
by its concavity to increase the size of the chamber in which the ossicula auditds 
(m.ml., m.k.) lie, and along which the facial nerve (VIT.) runs. A very small tract of 
skull-wall is seen between the pterygoids and the glenoid region, right and left, but 
the basis cranii is seen up the fore end of the presphenoidal region (p.s.), 
That is all cartilaginous, and in this marvellously stout little skull the whole beam 
has twice the thickness it has in Tutus’a, The basisphenoidal region is more than 
equal to the presphenoidal in extent, but its middle two-thirds only is ossified ; this 
basisphenoidal bone (b.s.) has all its four subequal sides concave ; its outer sides are 
pressed upon by the pterygoids. Then comes a tract of cartilage which is louger than 
the bone, but narrows, backwards, for its hind margin is between the most bulging 
part of the large cochleze. The basioccipital (b.0.) is lozenge-shaped, with the front 
und hind angle truncated; it is larger than the basisphenoid, and, like it, reaches 
the edges of the basal cartilage. The occipital arch is less by far than the auditory 
region, and the paroccipital region is but little marked—as in the Dasypodidee. The 
large condyles (0c.c.) are partly under the skull, yet they are well seen behind (fig. 4) ; 
they are obliquely reniform and enclose a large, subcircular foramen magnum (/-m.). 
The exoccipitals (e.0.) are separated by a tract equal, nearly, to their own width from 
the other occipital centres (b.0., s.o.) ; the hypoglossal (XII.) notches the bone in its 
lower or anterior edge on the right side, nearer to the auditory capsule than to the 
condyle. Still further forwards the 9th and 10th nerves (IX., X.) pass out, the basal 
cartilage being notched for them behind the capsules. 
These latter parts are very large, and wholly cartilaginous, at present ; the cochlea 
has the appearance of being composed of only two coils, for the proximal part is one 
large curved convexity, the distal or hemispherical mass lying in its concavity. Both 
the fenestra (fs.o., fr.) are seen in this view, and also the facial nerve (VII.), both 
along the tegmen, and at its exit behind the thick epihyal (e.hy.), which it notches. 
*The Unau comes very near the extinct Cwlodon in the structure of its palate ; compare these figures 
(Plate 8, fig. 1, Plate 9, fig. 1) with Rutuarpr’s admirable illustrations of that type (“ Kempedovendyr- 
sleeten Cornopon.” Copenhagen, 1878). 
