The chief character which distinguishes the Batrachians from the reptiles, leaving aside the metamorphoses, lies in the arrangement of the bones of the palate, where a large parasphenoid extends forwards as far or nearly as far as the vomers and widely separates the pterygoids.
In most of the former the palatines fuse with the vomers, whilst they remain distinct, unless entirely lost, in the latter.
Simultaneously on the vomers, the palatines, Rsvc, Lsvc, right the pterygoids and the parasphenoid in and left supesome of the Stegocephalia (Dawsonia, Seeleya, rior cavae.
Acanthostoma), on the vomers, palatines and Ta, Truncus arparasphenoid in many salamandrids (Pletho- teriosus.
Dontinae and Desmognathinae), on the vomers, Ao, Left aortic Pterygoids and parasphenoid (some Pelobates), arch.
On the vomers and parasphenoid (Triprion, P.A.
The batrachians they are confined to the vomers pericardium and palatines or to the vomers alone (37).