Four and twenty tailors went to kill a snail . . . Run, tailors, run, or she’ll kill you all e’n now. —Old Nursery Rhyme The sluggish snail has turned out to be far more deadly than the anonymous poet ...

Many marine invertebrates, like sand dollars and sea snails, spend their larval stage floating through the sea. Eventually, they detect chemical signals indicating that it’s time to metamorphose. Some ...