morphology of a frog
hind limb 
Long powerful articulated member attached to the terminal end of the trunk; it has five webbed toes used for walking, jumping and swimming.
web 
Fine membrane of skin connecting the digits of the foot; it stretches when the frog swims.
digit 
Terminal end of the limbs formed of various articulated bones; it has neither nails nor claws.
forelimb 
Short articulated member located behind the head; it has four digits and is used for walking.
lower eyelid 
Thin muscular membrane that is translucent and movable; it rises from the lower edge of the eye to protect and cleanse it.
mouth 
Anterior cavity of the digestive tract located on the ventral surface that allows food to be ingested.
nostril 
External orifice of the nasal cavity located above the mouth and having olfactory and respiratory functions.
snout 
Anterior round protruding portion of the head that forms the mouth and the nostrils.
eyeball 
Protruding organ of sight contained in the bony cavity at the top of the head used to perceive light intensity, motion and shapes.
tympanum 
Thin strong elastic membrane connected to the inner ear to capture acoustic vibrations.
upper eyelid 
Thick fixed membrane.
trunk 
Bony portion of the body to which the head and limbs are attached.