The mouth opens at one end and leads to a digestive cavity. Every cnidarians has at least two layers of cells that form its body wall. The body of a cnidarians may be shaped like a cylinder, a bell, or an umbrella An outer layer makes up the body covering, and an inner layer lines the digestive cavity. Many cnidarians have a third, or middle, layer consisting of a stiff, jellylike material that helps support the animal.

Jelly fish are cnidarians that has a bell- or umbrella-shaped body A polyp is a cnidarians that has a body shaped like a hollow cylinder. A polyp lives with one end of its body attached to the sea bottom

Adaptations some cnidarians to regenerate lost parts or even a complete body Hydrodtatic Skeleton. This type of skeleton is a skeleton where muscles surround a water-filled body cavity and the muscles are supported by this cavity

Cnidarians have radial symmetry - that means they have symmetry revolving around a center point. Cnidarians have 2 forms: Polyp (like sea anemone) and medusa (like jellyfish) The size is 100 ft (30 m) long and more than a ton (910 kg) in weight

The name scyphozoa means cup animals which describes the medusa, the dominant form of life cycle of this class. the size 12 millimeters to more than 2 meters across The habitat is Arctic to the warm tropical seas of the Pacific and Indian Oceans Their food source is Most jellyfishes are passive drifters that feed on living or dead preys: small fish, eggs, zooplankton and other invertebrates that become caught in their tentacles

The class hydrozoa includes about 3,700 species most of which live as colonial organisms in the ocean. The size of a hydrozoa is 6 to 9 centimeters (2.4 to 3.5 in) The habitat is Fern like hydrozoans can be found living on rocks and jetty piles Food source is mainly feed on daphnia and Cyclops

The name anthozoa means flower animals which is a fitting description for the approximately 6,100 marine species in this class. Over thousands of years, these polyps build up large, rock like formations known as coral reefs. The size is 10 in. (25 cm) in diameter Their habitat less than 150 ft (46 m), where sunlight penetrates Their food source is small fishes. Others consume organic debris

Class hydrozoa / Scyphozoan KINGDOM: Animalia PHYLUM: Cnidarians CLASS: Hydrozoa ORDER: Actinulidae FAMILY: GENUS: SPECIES COMMON: KINGDOM: Animalia PHYLUM: Cnidarians CLASS: Medusozoa ORDER: FAMILY: GENUS: SPECIES COMMON

CLASS ANTHOZOA KINGDOM: Animalia PHYLUM: Cnidarians CLASS: Anthozoa ORDER: FAMILY: GENUS: SPECIES COMMON

Dawkins, R. The Jellyfish’s Tale. In "The Ancestor's Tale." (2004) Houghton Mifflin Company, New York, New York. pp Dunn, Casey, and Rebecca R. Helm. "Cnidarian." World Book Advanced. World Book, Web. 22 Mar Arai, M.N. (1997). A Functional Biology of Scyphozoa. London: Chapman & Hall [p. 316].