118 
MR. W. K. PARKER OK THE STRUCTURE AND 
found, will most probably differ from it in one or other unimportant character, and yet 
correspond with it in non-essentials. 
This is a short skull (Plate 23, figs. 5 and 6); the breadth is as to the length as 
5 to 4, but the length is increased externally by the great retreat backwards of the 
quadrate condyles (q.c.), which make it, if measured by them, one-tenth more. 
It is also an extremely flat skull, and has a decurved snout; it is very much unlike 
the skull of any of the “ Ranidae” known to me, and the crania that answer to it best 
are not yet described. I must therefore give an account of it as it is, and then refer 
to it afterwards, when its image appears again in other types. The occipital condyles 
(■ oc.c .) have large, oval, posterior faces, but they project very little and are separated 
by a gentle emargination. 
With many deficiencies, that make it lie some depth below the “norma,” this skull is 
ultra-Ranine in its general form, for it is extremely depressed, the otic regions are wide 
wings, the jugal arch strongly bowed, and the hinge of the jaw is carried far behind 
the occipital articulation. The skull is of full width in the temporal region; then it 
does not become narrower, but much broader, towards the antorbital region. The 
margin above has a concave, and not a convex, outline; the walls do not bulge, but 
are scooped (fig. 6). 
The dilated ethmoidal region is made still wider by superorbital expansions ( so.h .), 
and in front the whole nasal territory is but little narrower than the ethmoidal. Thus 
the fore half of the cranium is in remarkable contrast with the hind half, and its 
copious cartilaginous matrix is very similar to that which is seen in Skates and even 
in the Chimeera; to make it still more archaic, the prenasal ( p.n .) is a thick decurved 
beak, such as is seen in an early stage of the embryos of many Yertebrata. 
The ossification of the occipito-auclitory region is generalised, being continuous on 
the same side ( pr.oe.o.) ; the synchondroses above and below ( f.m.) are rather wide 
and sub-equal. The fontanelle is quite covered ; it is single and lanceolate, with the 
narrow end forwards; the tegmen, behind, is short; in front, it rather appears, than 
is, extensive, for the ethmoid (eth.) is of great extent. The occipito-auditory bones 
( pr.o ., e.o.) nearly reach the fontanelle, under the roof-bones, above ; below, they touch, 
over the parasphenoid, but leave the vestibular floor unossified. Above (fig. 5), the 
bony matter leaves merely the tegmen tympani soft; it is very narrow fore and aft. 
In front, below, the bony matter almost encloses the foramen ovale (V.), and from 
thence half the interorbital region is cartilaginous in this tract; behind the middle of 
it is the large oval optic fenestra (II.). 
The girdle-bone [eth.) occupies more than a third of the endocranium ; it borders 
nearly a third of the fontanelle, and runs somewhat into the proper nasal territory. 
Below (fig. 6), it affects the wings a little ; above (fig. 5), its edge is rounder ; it runs 
quite clear of the superorbital “ eave. ” A cross-shaped expansion, below, marks off the 
shallow axils of this depressed bony mass; these fossae are large, but shallow. The 
cross is made more apparent by the extension forwards of the bony matter into the 
