DEVELOPMENT OF THE SKULL IN THE BATRACHIA. 
227 
The mandibles (Plate 43, fig. 6) are normal, the mento-Meckelian (m.mJc.) of good 
size, and the coronoid crest (cm) large. 
The stylo-hyal (Plate 42, fig. 9, st.h.) is thick and confluent, but not so thick as in 
Engystoma; the cerato-hyal (Plate 43, fig. 6, c.liy.) is broad, and in bending back 
has no lobe, but it has a distinct and large extra-hyal ( ex.hy .) as in some other kinds. 
The rest of these growths are very similar in the two kinds of Diplopelma (figs. 4 
and 6), but the notch is less, the lateral lobes larger, the thyro-hyals (t.hy.) diverge 
more, and in the space between these roots there is a larger and more solid basi- 
branchial bone ( b.br h); the heel in front of it is more or less calcified. 
The investing bones are more developed above and below than in the next, and the 
roof bones are complete along the inner margin. The fronto-parietals (fp.) are slightly 
convex, and fairly overlap the hind skull ; they also overhang the walls in the orbital 
region; altogether they are more normal than in the other species. They scarcely 
meet in front, and this interspace becomes wider between the nasals (n.) which are, 
however, large conchoidal plates of the normal form. The .marginal bones ( px ., mx., q.j.) 
correspond with those of the smaller species of Bufo, but the squamosal (sq.) is very 
feebly developed. The parasphenoid (fig. 9, pa.s.) is much more normal than in the 
next instance ; its main bars are sub-equal, and its hind part triangular. The vomers 
(v.) are Bufonine, and not very small; they are crescentic shells, notched both before 
and behind. There are no septo-maxillaries. This type of skull differs from the 
“ norma ” on the whole as much as that of Pseudopliryne: in some things more, as in 
the larger mesethmoidal bone ; in other things less, as in the greater retreat of the 
condyles of the quadrate, and the more normal form of the parasphenoid. These two 
species may be said to belong to the same group, and to lie on the same morphological 
and zoological level, and they might, with a little cutting and contriving, be put into 
the same genus. 
66. Diplopelma Berdmorei (?).'”'—Adult female; 1 inch 1 line long. Moulmin, 
Tenasserim. 
This skull is of the same length as the last, but its greatest breadth was the same, 
in this it is much greater than the length. The main figures (Plate 43, figs. 1, 2) are 
only magnified three-fourths as much as those of the skull of Engystoma (figs. 7, 8); 
thus the greatest breadth of these figures is the same, or nearly; the smaller, more 
magnified figures (figs. 7, 8) have both measurements equal as in the last, whilst those 
of this species (figs. 1, 2) show the length to be only nine-tenths of the breadth. 
This small skull has been metamorphosed very unequally ; in some things it only 
* This specimen, the gift of Jas. Wood-Mason, Esq., had lost its colour in the spirits; Dr. Gunther 
considers it to be most probably I). berdmorei; if not, to be a closely allied species ; it is larger than any of 
my specimens of D. ornatum vel rubrum, and differs much more from it in the structure of the skull than 
that species does from Engijstoma carolinense. 
2 G 2 
