DEVELOPMENT OP THE SKULL IN THE BATRACHIA. 
21 
Its fore margin sends out a snag; another follows this near the condyle for the 
lower jaw, and opposite this is a third, which has been described as tied by a ligament 
to the cornu trabeculae. 
The apex of the orbitar process rests upon a longitudinal crest of the palato- 
pterygoid band; this is the rudiment of the post-palatine ( pt.pa.) ; it projects, now, 
into the subocular space. 
The whole of the structure just described is not merely an hypertrophied epi-visceral 
element, it has given rise to a large extra-viscercd outgrowth. 
The “ cerato-visceral ” element is one-third the length and one-third the breadth of 
its own upper piece—but it is thicker ; this is the free mandible or Meckel’s cartilage 
(rnk,). This bar is strongly curved, having a long, terete, angular process behind its 
condylar face, which is a deep notch, like that of the human ulna. The shaft of 
the cartilage is both dilated and thick, and its subconcave end articulates with 
one side of the large sucking disk, the corresponding inferior labial (l.l.). 
This huge, almost horizontal mandibular arch, with its free bars turned inwards at 
little more than a right angle, is flush, in front, with the trabecular end of the 
chondrocranium. 
The four points of attachment to the basis-cranii of this long suspensorium shows a 
modified condition of that complete fusion of the two regions seen in the Chimseroids. 
In Dactylethra (ibid., Plate 56) this state of things is intensified, and in Pipa 
(ibid., Plate 60, fig. 3) the membranous space between the basal and lateral cartilages 
is reduced to a small crescentic slit. 
The larval Ranine skull may therefore be said to be, in this respect, a specialisation 
and dissection, so to speak, of the Chimaeroid type of skull; on the whole, it is much 
more like that of the Lamprey. 
This immense development of the first epi-visceral element is correlated with the 
suppression of all those that should succeed ; only afterwards, when this part has been 
relatively lessened, and greatly modified, does even that of the next succeeding arch 
appear, not then as a mere facial bar, but specialised to auditory purposes, as the 
“ columella.” 
But the “ cerato-hyal ” (Plate 2, fig. 7, c.hy.) is at present very large, several times 
larger than its counterpart of the mandibular arch (rnk.). 
It has a dilated, fan-shaped distal expansion (fig. 7), a gently convex pyriform 
condyle ( hy.c .), and a curved upper spike, the rudiment of the stylo-hyal ( st.h .) or 
upper end of the bar. The basi-hyal ( b.hy .) is still membranous, but it is followed by 
a solid basi-branchial ( b.br .); these parts will be described in a corresponding larva of 
R. pipiens, and in a riper larva of this same species. 
The ossifications in this stage are, first, a roundish patch of bone on each side, 
formed in the substance of the cartilage, close inside the aperture for the 9th and 
10th nerves; these are the ex-occipitals ( e.o ., IX., X.). 
The next are formed in membrane, outside the cartilage ; they are the fronto- 
