The skull generally lacks a sagittal crest; and the condyle of the lower jaw is transversely elongated.
The latter is, in comparison with mammals, represented by its middle portion only, the vermis; in a sagittal section it shows an extremely well developed arbor vitae, produced by the transverse, repeated folding of the whole organ.
The first is a ventral flexure in the antero-posterior or sagittal plane; the result of this is to approximate the two ends of the alimentary canal.
There is generally no sagittal crest to the skull; and the condyle of the lower jaw is transversely elongated.
It showed acceptable repeatability in the sagittal and frontal plane kinematics, but not in the transverse plane parameters (rotation angles ).