Basic Anatomy Defined




Size and shape of the eyes vary between shark species.  Some are elongated while others are round. In some the pupil is a black slit, while in others the pupils are obscured and the entire eye is black.

Another interesting note is that some sharks have a movable third eyelid called a "nictitating membrane," which can completely cover and protect the eye. This nictitating membrane is similar to that of the ordinary house cat.