Order Cydippida:

Ctenophores in order cydippida are egg-shaped and lack tentacles.
Pleurobrachia pileus
Pleurobrachia pileus is a small, oblong or spherical ctenophore that grows to be about 1-2.5cm long. It has two very long tentacles, which may be up to 20 times its body size and can be retracted into the body. These tentacles are used to trap prey, bearing adhesive cells called colloblasts. They feed on other P. Pileus, fish eggs and larvae, and copepod crustaceans. Like other ctenophores, it swims by beating eight rows of cilia rhythmically. This species is hermaphroditic—sperm and eggs are released in the water, thus fertilization occurs externally. Most individuals die immediately after spawning. P. Pileus are preyed upon by small fish. It inhabits shallow waters and is most commonly found in the North Atlantic region in summer and early autumn.


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