#semaeostomeae

The Lion’s Mane Jelly (Cyanea capillata) (image 3) is one of the largest jellyfish, with the largest recorded specimen having a bell width of 210 cm (7 ft) and tentacles around 36.6 m (120 ft) long.

While most jellies are exclusively marine, the Bay Nettle (Chrysaora chesapeakei) ventures into the Chesapeake Bay’s brackish water all the way up into the freshwater of Baltimore’s Inner Harbor.

The Giant Phantom Jelly (Stygiomedusa gigantea) (image 4) is a deep sea jellyfish that is rarely seen, with only around 110 sightings in 110 years. It thought to be one of the largest invertebrate predators of the ocean's midnight zone and twilight zone, with an umbrella-shaped bell that can grow up to 1 m (3.3 ft) in diameter and paddle-like arms that can grow up to 10 m (33 ft) in length. The bell's pliant tissue allows for the jellyfish to stretch 4 to 5 times its size, presumably to engulf their prey. They do not have any stinging tentacles and instead use their arms to trap and engulf their prey which consists of plankton and small fish. The Giant Phantom Jelly has a symbiotic relationship with the Pelagic Brotula (Thalassobathia pelagica), for which it provides food and shelter beneath its massive billowing bell, while the fish aids the jelly by removing parasites.

The Mauve Stinger (Pelagia noctiluca) is a fairly small purple jellyfish that is able to bioluminesce. Light is emitted in the form of flashes when the medusa is stimulated by turbulence created by waves or by a ship's motion. Unusually among cnidarians, Mauve Stingers are able to consume phytoplankton, alongside copepods and other usual planktonic fare.