DEVELOPMENT OF THE SKULL IN THE BATRACHIA. 
239 
in front of the basal plate is deep and round; the plate itself is very long’, has only 
anterior lateral lobes, which are small and auriform ; the long, very narrow cartilage 
(b.h.br.) is subcarinate, hollow above, and ends, behind, in two long, curved, highly 
divaricated thyro-hyals ( t.hy.). 
The investing bones are freer from the less ossified endocranium in this species; the 
fronto-parietals (fp.) are separate, throughout, and show but little want of symmetry; 
their temporal angle is but little produced, and their fore ends are narrowed a little 
and oblique, they scarcely cover the fontanelle. The orbital edge is sharp, and the 
descending lamina thick (fig. 8), especially behind. The left nasal ( n .) is the larger 
of the two, and projects further forwards; these bones are ovoidal, very convex, and 
show something of the ornamentation seen in Bufo ornatus and Otilophus mar- 
garitifer. 
The feeble prem a xil l ories (px.) run far across as a sub-arcuate band under the snout, 
and their nasal processes are tilted forwards; these carry the inner labials ( u.l h), to 
which are attached the outer valves (u.l 2 .). 
As in the other two, there is no septo-maxillary; the maxillaries (mx.) are high, 
roughly rounded in front, and gradually end in a blunt point, which is free. Their 
sides are sculptured, considerably, like the lateral part of the large, hollow nasals on 
which they rest (fig. 8). The left is considerably shorter than the right, and all 
that side of the face is drawn forwards. On the left side the jugal arch is unfinished 
for an extent equal to one-fifteenth part of the length of the skull; on the right side 
only half as far. The small tooth-like quadrato-jugals (qj) have their broad base 
grafted on the quadrate (q. ); the left is the smaller bone. 
The squamosals ( sq.) are intermediate between those of the other two kinds; the 
supratemporal part is narrow, as in P. cruciger (Plate 41, fig. 1), but this large bone 
is bent on itself—almost as much as in P. varius (Plate 41, fig. 8). 
The parasphenoid ( pa.s .) is similar to that of the other two, but the cochleate 
median part is wider than the extended wings; where they are given off the bone is 
elevated on each side into a crescentic ridge, but there is no median apophysis imita¬ 
ting the triangular hinder part; the whole bone is considerably less than half the 
length of the skull. 
The vomers ( v .) are instructively separate in this species, explaining the ridges that 
defend the inside of the inner nostrils in the other two kinds. 
They lie inside these small passages ( i.n .), which like the outer openings are very 
wide apart; their shape is normal, they are cochleate, have a pre- and a post-narial 
spur, and an anterior lobe bent outwards upon the main part; they are very accurately 
formed of a thin layer of dense bone, and are merely deficient in size, and in being 
edentulous—as in other Toads. 
These three species have skulls that differ from one another more than whole 
Families of genera would be seen to do in highly specialised groups of Vertebrata, 
such as the Teleostean “ Acanthoptera,” or many groups of Carinate Birds. They come 
