The brain consists of a forebrain, midbrain, and hindbrain. Among reptiles, the degree to which the forebrain, particularly its upper part, the pallium, is elaborated varies. Turtles, the tuatara Sphenodon, and some lizards have relatively modest pallial specializations; snakes and other lizards have a greater degree; and crocodiles exhibit the most specialized pallium. The roof of the midbrain, the tectum, is well developed in all reptiles, whereas the roof of the hindbrain, the cerebellum, is much more modestly developed than it is in mammals and birds.
Characteristics
The major regions of the brain are the hindbrain, midbrain, and forebrain; the latter is composed of the diencephalon and telencephalon (Fig.
1).
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