Among the burrowing and tubicolous forms it is not uncommon for the body to be distinguishable into two or more regions; a "thorax," for example, is sharply marked off from an "abdomen" in the Sabellids.
It is of nocturnal and burrowing habits, and feeds on decomposed animal substances, larvae and termites.
The majority are distinguished from snakes by the possession of two pairs of limbs, of external ear-openings and movable eyelids, but since in not a few of the burrowing, snake-shaped lizards these characters give way entirely, it is well-nigh impossible to find a diagnosis which should be absolutely sufficient for the distinction between lizards and snakes.
The head is very small and not distinct from the neck, a usual feature in burrowing snakes and lizards.
Gunther characterizes the chief categories as follows: - (I) Burrowing snakes, which live under ground and but rarely appear on the surface.