DEVELOPMENT OF THE SKULL IN THE BATRACHTA. 227 



The mandibles (Plate 43, %. C) are normal, the mento-Meckelian {m.onk.) of good 

 size, and the coronoid crest {((v.) large. 



The stylo-hyal (Plate 42, fig. 9, st.h.) is thick and confluent, but not so thick as in 

 Enc/tjstoma ; the cerato-hyal (Plate 43, fig. 6, c.hy.) 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 Dij^lojiehna (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 mjore solid basi- 

 branchial bone (b.br^.) ; the keel in front of it is more or less calcified. 



The investing bones are more developed above and below than in the next, and tbe 

 roof bones are complete along the inner margin. The fronto-parietals (f.'jy.) 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, jXf.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 Pseudophryne : in some things more, as in 

 the larger mesethmoidal bone ; in other things less, as in the gi-eater 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. DijAopehna 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, whUst 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-Masox, Esq., had lost its colour in the spirits; Dr. Gunther 

 considers it to be most probably D. berdmorei ; if not, to be a closely allied species ; it is larger than any of 

 my specimens of D. omatum vel rtibrum, and differs much more from it in the structure of the skull than 

 that species does from Enijystoma carolinense. 



2 G 2 



