There are approximately 200 recognized species of jellyfish, which vary greatly in size, shape, and color. The smallest jellyfish may be less than an inch in diameter and the largest may have tentacles that stretch over a hundred feet long. Jellyfish have limited sense organs, but can still smell, taste and remain balanced in water. Special sacs located on the rim of their bodies help jellyfish maintain their balance. When a jellyfish shifts too far to one side or the other, the sacs stimulate nerve endings that contract the organism’s muscles, reorienting the jellyfish in the correct direction. Jellyfish also have light sensing organs that can distinguish light from dark, in addition to chemoreceptors, which can sense both smells and tastes.