THE MORPHIC FIELDS OF ANIMAL SOCIETIES SCHOOLS OF FISH
In vertebrates, the coordination of individuals within a group is sometimes so close that it is almost impossible not to think of them as a kind of composite organism. Many species of fish form schools or shoals, and at a distance a fish school resembles a large organism. Its members, numbering up to several million, swim in tight formations, wheeling and reversing in near unison. The fish do not follow particular leaders. When the school turns to the right or left, individuals formerly on the flank assume the lead.