Cutaneous respiration
The skin of amphibians is a major site of respiration in all species for which measurements are available. Cutaneous respiration is the sole respiratory mode of lungless salamanders (family Plethodontidae) which lack lungs entirely yet constitute the largest family of salamanders. Cutaneous respiration in frogs and other amphibians may be the primary respiratory mode during colder temperatures.
Pacific tree frog
Skin color is produced via pigment cells called chromatophores. Three types of chromatophores are commonly found in amphibians: Xanthophores, which contain yellow, orange, or red pigments and are found uppermost on the dermis; iridophores, which lie below the xanthophores and function by reflecting and scattering white light up through them (in the case of "Pseudacris regilla" and many other North American frogs, iridophores reflect blue light through the yellow pigment cells above to create a green frog) and melanophores, which are the deepest pigment cells and are responsible for the presence of black and brown pigments.