mouth arm

Four long tentacles, commonly called mouth, or oral, arms, hang from the centre of the underside, where the mouth of the jellyfish is located. In most cases, 24 other, thinner extensile tentacles hang from the rim of the bell. Uniformly ciliated larvae, or planula, are brooded within the adult. The…

…jellyfish the frilly projections (oral arms) that extend down from the underside of the body are fused, obliterating the mouth and forming a spongy area used in filter feeding. Marginal tentacles are lacking, and the gelatinous bell is firm and warty. In species whose life cycles are known, there…