In the existing Proteidea

In the existing Proteidea, and in the Gymnophiona, the vertebral centra are amphicoelous. In the Salamandridea they are opisthocoelous. In Pipa and Bombinator they are also opisthocoelous, but in other Batrachia they are, for the most part, procoelous, but vary in different regions, some being biconvex and some biconcave.

The first vertebra, or atlas, presents two articular cups to the condyles of the skull, but there is no specially modified axis vertebra.

The transverse processes may be simple, but in the Labyrinthodonts, and in the existing Salamanders, they are divided into two processes - an upper tubercular, and a lower capitular, process. When the transverse process is thus divided, the proximal end of the rib is correspondingly split into a capitular and a tubercular process.