100 
MR. W. K. PARKER OK THE STRUCTURE AND 
they each grow into a large falcate tract which nearly reaches the end of the 
fontanelle, and then come within a moderate distance of each other, near the middle. 
The roof of cartilage has a concave edge behind, as well as in front; and from the 
curved tracts of bone the cartilage runs forwards on each side to the end of the 
fontanelle, and exists, between the prootic and girdle-bone, as an obliquely four-sided 
space, which occupies about a fourth of the orbital edge of the skull. 
Below (fig. 6), the prootics and ex-occipitals being of less extent, the cartilage is 
present as a large wedge on each side running into the floor of the skull ; nearly the 
whole vestibular floor is unossified, and in front of the ear, the prootics, not completely 
surrounding the foramen ovale (Y.), leave a tract of cartilage which surrounds the whole 
of the optic fenestra (II.). 
The outer edge of the girdle-bone (eth.) margins half the orbital rim; it is only 
typically developed as to extent, a clear tract of cartilage separating it from the 
orbital fenestra; while in front it only just reaches the long septum nasi (s.n.). 
This bone is large, because of the width and size of the matrix in which it is 
formed, and not because of overpassing its own proper territory, as in several kinds 
of Anura. 
On each side the ethmoid bone does not quite cover the wings of the ethmoidal 
cartilage (fig. 5,pa.), from which the ethmo-palatine bars are extended; these transverse 
bars and all the huge nasal region, are left unossified. 
The roof of the nose (fig. 5, al.sp.) is very wide and enlarges from before, backwards ; 
the floor of the nose (fig. 6, s.n.l.) is equally wide, and lessens from before, backwards. 
Here we see what has taken place since the larval stage—viz. : that the huge cornua 
trabeculae are now united together by a solid intertrabecular tract, ending, in front, in a 
rounded knob; whilst near this knob, on each side, a small ligular fork has been 
given off which passes between the laminae of the premaxillary; this small secondary 
“ cornu ! is the pro-rhinal ( p.rh .). Above (fig. 5), the nasal roof throws the external 
nostrils ( e.n.) far apart; each lamina has a rounded emargination behind the nostril, 
and then expands again until it passes into the substance of the ethmo-palatine 
band (fig. 5, pa.) 
That band is twice the normal width, and spreads externally into a large fan-shaped 
plate (fig. 6). 
The hind horn of this expansion ( pt.pa .), as it passes into the pterygoid, becomes a 
mere thread, and the rest of the arch, although normal, is very feeble, and its two 
forks, the pedicle and quadrate region ( q.c .), are short. 
In this species it is not difficult to detach the palatine and pterygoid bones (pa., 
pg.), for they graft themselves only slightly on the cartilage within. The palatines 
(fig- 6, pa.) are flat, lathy bones, rounded only at their inner end; they are sub- 
sigmoid, with sinuous edges, and an abrupt outer end ; their inner ends pass largely 
under the face of the girdle-bone. 
The pterygoids (figs. 5 and 6, pg.) are but little larger than the palatines ; they 
