Ctenophores are vaguely similar in appearance to jellyfish, have eight "comb rows" of fused cilia that are arranged laterally along the sides of the animal and used primarily for locomotion. Many ctenophores have two long tentacles, but some lack tentacles completely. There are about 100 modern species of these marine animals. One of the most familiar genus of Ctenophore is Mnemiopsis. Due to their soft and fragile bodies, the fossil record for comb jellies is poor. A possible Ctenophore is known from the Middle Cambrian.
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