EARTH SCIENCE > BIOLOGICAL CLASSIFICATION > ANIMALS/VERTEBRATES > AMPHIBIANS
Amphibians are craniates with a permeable skin across which respiration
can take place. Their life cycle includes a shell-less egg which gives
rise to a distinct larval form. The amphibians are free living in fresh
water and on land (some are arboreal) but all are dependent on water or
Burn, David M. Animal World. 1980. Octopus Books Ltd. London.