Frog has different types of sense organs, namely organs of touch (sensory papillae, taste (taste buds), smell (nasal epithelium), vision (eyes) and hearing (tympanum with internal ears).
Eyes and internal ears are well-organised structures and the rest are cellular aggregations around nerve endings.
Eyes in a frog are a pair of spherical structures situated in the orbit in the skull.
These are simple eyes (possessing only one unit).
The external ear is absent in frogs and the only tympanum can be seen externally.
The ear is an organ of hearing as well as balancing (equilibrium).
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Presence of external ear or pinna is a typical mammalian character. It is not seen in amphibians.