Some sponges and cnidaria have this kind of body form.

Cnidaria is a phylum with about 11,000 species of animals.

This is characteristic of the phylum now called the Cnidaria.

Cnidaria have no brains or even central nervous systems.

The Cnidaria often have complex life cycles, with both sexual and asexual reproduction.

Cnidaria begin to differentiate their nervous systems in the late gastrula.

Corals themselves are tiny animals which belong to the group cnidaria (the "c" is silent).

They were once considered as parasitic protozoa, but are now known to be members of the phylum Cnidaria.

Corals are formed by small animals, the polyps of the phylum Cnidaria.

Cnidaria give their symbiotic algae carbon dioxide, some nutrients and a place in the sun.

Their appearances are that of basic invertebrates such as flat worms, mollusks, and cnidaria.

All known cnidaria can reproduce asexually by various means, in addition to regenerating after being fragmented.

Taxonomic classification systematics within the Cnidaria, as with all organisms, are always in flux.

The sister group of the Cnidaria is the Ctenophora, the comb-jellies.

The nematocyst is the stinging apparatus of the phylum Cnidaria.

Cnidaria take their name from special cells which have organelles that sting: the nematocysts.

Hydra, a genus belonging to Cnidaria, is used as a model organism to study nerve nets.

They may have represented cnidaria, but their affinity within the Metazoa is difficult to constrain.

The group was previously thought to be related to the corals and placed in the Phylum Cnidaria.

She was a specialist in Porifera and Cnidaria.

Nephtheidae is a family of soft corals in the phylum Cnidaria.

Medusa jellyfish are a life stage exhibited in some species of the phylum Cnidaria.

Most researchers believe them to be basal among the bilateria, slightly more derived than the Cnidaria.

The Hydrozoa are a class of the phylum Cnidaria.

First Cnidaria, and probable annelids, about 580 million years ago, in the Ediacaran period.

Once the water began to fill with animals, cnidarians took on their current form.

The findings have also attracted scientists to cnidarians as a model to understand the human body.

Over 30 types of cnidae are found in different cnidarians.

This nervous system allows cnidarians to respond to physical contact.

It gives rise to muscles, the heart and other organs not found in cnidarians.

These new insights into cnidarians have prompted major initiatives to understand them better.

All cnidarians have a mouth in the center of their bodies, surrounded by tentacles.

Hydra, which are cnidarians, have a nerve net throughout their body.

Craterolophidae is a family of cnidarians in the order Stauromedusae.

Cnidarians often have huge numbers of cnidocytes on their tentacles.

The oldest fossils that can be confidently called cnidarians are just 540million years old.

Prey of cnidarians ranges from plankton to animals several times larger than themselves.

All the species in the family are found in a close symbiosis with cnidarians.

Hawksbills close their unprotected eyes when they feed on these cnidarians.

In contrast, cnidarians seem to lack such symmetry completely.

Unlike other cnidarians, anthozoans do not have a medusa stage in their development.

One species has also been recorded on various cnidarians [1].

Thecaphora was also proposed for the order of cnidarians usually known as Leptomedusae.

They classified cnidarians as "zoophytes," somewhere between animal and plant.

They are much older, having evolved in the common ancestor of cnidarians and bilaterians 600million years ago.

It is not a fish but a cnidarian, a spineless, soft-bodied animal.

As a cnidarian, this jellyfish has an asexual and sexual reproduction.

Later, Mackenzia is thought to be a cnidarian and appears most similar to modern sea anemones.

The nervous system is unusually advanced for cnidarians, or even than in the polyps of the same species.

The original interpretation was that Chondroplon is a chondrophorine cnidarian.