- Radially symmetrical, diploblastic multicellular animals with a tissue grade of organisation.
- Aquatic, freshwater or marine solitary or colonial forms which may be free swimming or sedentary.
- Body has a mouth at the oral end which leads into a spacious cavity called gastrovascular cavity or coelenteron.
- Presence of long, hollow structures called tentacles used for locomotion and food capturing.
- Presence of peculiar type of cells called cnidoblasts, nematocysts or stinging cells in the ectoderm, especially in the tentacles, used for offence and defence.
- Digestion is both intracellular and extracellular.
- Respiration and excretion by simple diffusion.
- Presence of a network of nerves spread all over the body.
- Many forms exhibit polymorphism, wherein different types of individuals are present in a colony for different functions. These individuals are called Zooids.
- Reproduction asexually (external budding) or sexually (formation of gametes).
fig. 10.7 - Examples of Coelenterata
The phylum is divided into three classes
| Characteristics | Class Hydrozoa | Class Schyphozoa | Class Anthozoa |
|---|---|---|---|
| Habitat | Fresh water or marine | Marine | Marine |
| Body Form | Polypoid or Medusoid | Medusoid | Polypoid |
| Example | Hydra, Obelia Physalia (Portuguese man of war) | Aurelia Cassoprea (Jelly fishes) | Sea anemone Astrea Fungia and other Corals |
fig. 10.8 - Anatomy of Hydra
Related Questions
phylum cnidaria coelenterata: There are two other groups Cnidaria and Ctenophora:A.) Cnidaria also known as.....
