At first glance, the lettuce sea slug (Elysia crispata) looks like a leafy underwater alien. But what’s hiding inside its frilly green body is far more fascinating than its salad-like appearance.

SOME SEA slugs are kleptomaniacs. Elysia crispata, a species of these marine molluscs found in the western Atlantic and the Caribbean, is among the most notorious. When the slugs eat algae, their ...

Elysia crispata, or the lettuce sea slug, has a ruffled exterior that is reminiscent of a head of iceberg lettuce, especially when it takes on a greenish hue. These lettuce-like folds are actually ...