The external structure of the frog and its skeleton.

The frog has a short and wide body, which smoothly and without visible joints turns into a large flat head. The frog has no neck and tail. On the sides of the head are protruding eyes with lower and upper eyelids. Below the lower eyelid is a thin nictitating membrane, which is characteristic of most terrestrial vertebrates.
Above the large mouth is a pair of nostrils that have a check valve. The forelimbs are short and have four toes. On the contrary, the hind limbs are very long and can have up to five fingers, which are connected by a wide swimming membrane. All fingers are without claws. On the back of the body there is a single outlet – the cloaca. The entire body is covered with bare skin, which, thanks to the constantly secreted mucus, is always moist. The frog’s skin performs the function of respiration and water exchange; it is attached to the body not throughout the body, but only in some areas, between which the lymphatic sacs are located.