Eastern Emerald Elysia

Adult Elysia chlorotica are usually bright green in color owing to the presence of Vaucheria litorea chloroplasts in the cells of the slug's digestive diverticula. Since the slug does not have a protective shell or any other means of protection, the green color obtained from the algae also functions as a camouflage against predators. By taking on the green color from the chloroplasts of the algal cells, the slugs are able to blend in with the sea bed, helping them improve their chances of survival and fitness. However, they can occasionally appear reddish or greyish in colour, which is thought to depend on the amount of chlorophyll in the branches of the digestive gland throughout the body. This species can also have very small red or white spots scattered over the body. A juvenile, prior to feeding on algae, is brown with red pigment spots due to the absence of chloroplasts. Elysia chlorotica have a typical elysiid shape with large lateral parapodia which can fold over to enclose the body. Elysia chlorotica can grow up to 60 mm in length but are more commonly found between 20 mm to 30 mm in length.

Elysia chlorotica can be found along the east coast of the United States, including the states of Massachusetts, Connecticut, New York, New Jersey, Maryland, Rhode Island, Florida, (east Florida and west Florida) and Texas. They can also be found as far north as Nova Scotia, Canada.

This species is most commonly found in salt marshes, tidal marshes, pools, and shallow creeks, at depths of 0m to 0.5m (50cm) .