A burrowing existence
Another group of Amphibians called the caecilians are also limbless, but are adapted to a burrowing existence and almost resemble earthworms. Their anatomy is so different from the salamanders that they are classified in the order Gymnophiona. They have several primitive features such as the retention of small scales in the skin and a very short tail. The solidly build skull, the elongated body comprising as many as 270 vertebrae, no internal girdles for supporting limbs and blindness (compensated by having extendable, sensorytentacles) are all adaptations to a burrowing existence. However, they are carnivorous and have mouths with a large gape.