As a member of the Phylum, Cnidaria, hydra arose early during metazoan evolution before divergence of the protosome and deuterostome branches. Its body plan is organized as a gastric tube with a ...

Hydra is a genus of tiny freshwater organisms within the phylum Cnidaria-- the phylum that includes jellyfish, sea anemones and corals, among others. Most hydra measure less than half an inch.

Hydra are inch-long freshwater creatures that resemble a floating tube with a grasping appendage at one end and a cluster of tentacles at the other. They belong to the phylum Cnidaria ...

Hydra are simple animals that, along with jellyfish, belong to the phylum cnidaria. Cnidarians first emerged 600 million years ago. "We determined which genetic 'gateway,' or ion channel ...