Lungs.
Frogs minimum only 50 mm, only one of the thumb is long, big have 300 mm (a foot long), pupil is horizontal, the skin is smooth tongue, two forks, in front of the mouth, tongue, with the long back orifice, suddenly turned out to catch bugs. Three eyelids, one of which is a transparent, in the water, with two other eye protection and eyelid is common. Head on both sides of the two sound, can produce resonance, amplification. Smaller higher frequencies of varieties calls.