120 
ME. W. K. PARKER OK THE STRUCTURE AHD 
The condyle for the mandible (q.c.) is large, oblique, and reniform, and has the inner 
trochlea twice the size of the outer; the hinder and outer fork of the pterygoid bone 
runs vertically, splint-like, inside this far-retreated part of the suspensorium. The 
large Eustachian opening (fig. G, eu.) is, by this, made to turn backwards, as well as 
outwards; its hind margin is a thick fibrous ligament. 
The mandible (fig. 7) is quite normal and of great length, answering to the extent 
of the gape; the mento-Meckelian part ( m.mk.) is large, and so is the cylindroidal 
condyle ( ar.e .); the cartilaginous bar (ink.) is but little affected by the trough-shaped 
“ articulare ” (ar.) ; the dentary (d.) is a little more than half the length of the 
mandible. 
The “annulus” is very remarkable ; it is large (Plate 23, fig. 7, a.ty.), thick at the 
edges, oblong in shape, and whilst one horn is attached to the fore part of the 
portico formed by the squamosal (sq.) over the tympanic cavity, the other horn passes 
behind and under the hind part; its position is oblique, being carried backwards, 
below, b} r the suspensorium and its splint (q., sq.). 
The stapes (fig. 10, st.) is thick and of a short-oval shape, with the fore margin 
emarginate. The columella fits by its thick, bilobate, scooped apex, within and around 
the fore part of the stapes. The inter-stapedial (i.st.) is represented by the larger, 
unossified lobe ; but it is doubtfully segmented. The medio-stapedial ( m.st .) has also 
some cartilage on the lesser lobe, and the thick bony end carrying the cartilage is 
almost discoidal. The narrow shaft is bent almost at a right angle on the dilated 
proximal part, and runs more than half way to the distal end. That end, gradually 
thickening to its middle, is the extra-stapedial (e.st.) ; at first it is merely a continuation 
in the same line as the shaft, but its distal two-thuds is bent down at a little more 
than a right angle, is thick below, and cochleate above. There is no supra-stapedial. 
This generalised, but large, columella is seen (fig. 7, e.st.) to emerge from the cleft, 
and then to pass, downwards and outwards, inside the membrana tympani. So far 
are these parts carried outwards, backwards, and downwards, that in the upper view 
(fig. 5, a.ty.) they are scarcely seen when the eye is focussed to the upper face of the 
skull; hence the apparent minuteness of the annulus in the figure showing that aspect. 
I could find no cartilage in the hyoid arch from the Eustachian opening downwards 
until I reached the hypo-hyal region. There (fig. 8, h.hy.), there is a falcate hypo-hyal 
lobe which passes backwards and inwards to a basal plate of normal size (b.li.br.), and 
with the usual small posterior wings, and bony, divergent thyro-hyals (i t.hy .); but there 
are no anterior wings to the basal plate. Here the absorption of the hyoid band is 
equal to what is seen in Pipa. 
The investing bones, like those of the endocranium, are very unlike what we see 
in Rana, and in the “ ftanidse ” generally. 
The fronto-parietals ( f.p.) just overlap the fontanelle and the side-walls of the cranial 
cavity; they are almost square over the hind part of that cavity, and then expand 
forwards to their end. Their hind margin has a pair of shallow notches, and their fore 
