72 MR. W. K. PARKER ON THE STRUCTURE AND 
lower arches than that of the young Unau (Plate 9), for the fixed part of the hyoid 
arch (epihyal, ey.) has formed a “ tympanohyal” ossification (fig. 9, between fr. 
and IX., X.) in front of the stylomastoid foramen (VIL.), separate from the opisthotic 
(op.); the rest of the arch (fig. 6) has become free. 
The occipital arch, the base of which has already been described, is here seen, show- 
ing a semi-inferior, almost cireular foramen magnum (f.m.), convex sub-reniform con- 
dyles (0c.c.), exoccipitals with a low par-occipital ridge, and the lower edge of the 
large supraoccipital (s.o.). All the bones, here, are separated by a moderate tract 
of cartilage ; in front of that which runs sinuously inwards and forwards, between the 
basal and side pieces, we see the hole for the hypoglossal nerve (fig. 9, XII.) lying in a 
notch of the exoccipital (e.0.). 
The upper view (Plate 10, fig. 2) shows the form of the skull best, in its resemblance 
to a small gourd, the nasal labyrinth merely forming the neck to the bulbous cranium, 
Here an unossified endoskeletal tract of the snout («/.n.) finishes the upper end, 
and an ossified tract, the wide superoccipital (s.0.), finishes the lower ; all the rest, as 
seen in this view, is composed of paired investing bones. 
The emarginate space in front of the nasals shows a considerable amount of the 
double narial tube, ending near the fore end in the lateral nostrils (e.n.). 
The nasals (n., line too short), notched in front, widen, wing-like, at their frontal 
end, and are somewhat pinched at their sides. Just the top of the feeble facial plate 
of the premaxillaries (pw.) can be seen here, followed by the ascending part of the 
maxillaries (mx.), into which is set the small perforated lacrymal (/., /.c.), and from 
which grow the feeble threads that remain of the jugals (/.). 
The frontals (f/) are notched at their fore angle by the lacrymal wedge ; they then 
expand a little, and contract again, to finish the “neck” of the “ gourd.” 
From this neck, or waist, at the front third of the badly enclosed orbits, the whole 
cranium swells into its bulb, with but little injury to its neatly oval form, until we 
come to the gentle median projection of the supraoccipital. 
There is but little difference in the length of the frontal and sagittal sutures (see 
also fig. 3, f, p.); but these bones are not finished where they should pass into each 
other ; there the sutural teeth are large enough for a very much larger type, just as 
we find in the Caducibranchiate Salamandrians (see. Trans. Linn. Soc., ser. 2, vol. 2, 
plate 18, Cynops; plate 21, Spelerpes and Desmognathus). Here, in this dwarfed 
arboreal type, the fontanelle (fo.) is bilobate, and fills in slowly, reminding the 
observer of the numerous dwarfed arboreal kinds of Anura (Tree-frogs) that abound 
in the same primzeval forests, the companions of this very type. 
But the side view (fig. 3) shows some of the most remarkable things in this 
arrested type of skull; this may be compared with the similar figure given of the 
embryo Unau (Plate 8, fig. 3); such a comparison will show a likeness between the 
two that is very remarkable. 
One thing may be stated here, namely, that the length of the basifacial axis, from 
