There are more than two hundred species of jellyfish floating in the oceans, bays, gulfs, or sounds of the world. They are not fish at all but invertebrates that have no head, brain, heart, eyes, ears, or bones. They are well adapted to a drifting, predatory life. Zentner describes some of the ones common to North Carolina waters, including the moon jellyfish, sea nettle, mushroom jellyfish, and lion's mane. The lion's mane is the world's largest, measuring eight feet across with tentacles that reach one hundred feet.