t)EVELOPMEXT OF THE SKULL I\ THE BATRACHIA. 239 



ill front of the liasal plate is deep and round ; the plate itself is very long, has only 

 anterior lateral lobes, which are sniall and auriform ; the long, very narrow cartilage 

 {JjJi.hr.) is subcarinate, hollow above, and ends, behind, in two long, curved, highly 

 divaricated thyro-hyals (t.hij.). 



The investing bones are freer from the less ossified endocranium in this species ; the 

 fronto-parietals {f.p.) are separate, throughout, and show but little want of symmetiy ; 

 their temporal angle is but little produced, and then- 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 («.) is the larger 

 of the two, and projects further forwards ; these Ijones are ovoidal, very convex, and 

 show something of the ornamentation .seen in Bufo ornatus and Otilophus mar- 

 garitifefi\ 



The feeble premaxillaries {px.) run far across as a sub-arcuate band under the snout, 

 and their nasal processes are tdted forwards; these carry the inner labials (u.l^.), to 

 which are attached the outer valves {u.l~.). 



As in the other two, there is no septo-maxUlaiy ; 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 latei-al 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-hke quadrato-jugals (7./) have their broad base 

 grafted on the quadrate {q.); the left is the smaller bone. 



The squamosals [sq.) are intermediate between tho.se 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 ofi" the bone is 

 elevated on each side into a crescentic ridge, but there is no median apophysis imita- 

 ting the triangular hinder pai't ; the whole bone is considerably less than half the 

 length of the skull. 



The vomers (i'.) ;u-e instructively separate m tliis species, explaining the ridges that 

 defend the inside of the inner nostrils in the other two kinds. 



They he inside the.se small passages {i.n.), which like the outer openings are very 

 wide apart; then- shape is normal, they are cochleate, have a pre- and a post-nariai 

 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 iu size, and in being 

 edentulous — as in other Toads. 



These thi-ee species have skulls that differ from one another more than whole 

 Families of genera would be seen to do in higlily speciahsed groups of Vertebrata, 

 such as the Teleostean " Acanthoptera," or many groups of Carinate Birds. They come 



