Akanksha Soni, Academic Content Writer at Edumarz
Phylum Coelenterata:-
Coelenterata is also known as Cnidaria.
It is more advanced than sponges.
Coelenterata has true tissues.
They are aquatic, mostly marine.
Coelenterata is sessile or free-swimming.
They have radial symmetry but sea anemones have bilateral symmetry.
The cnidaria name is derived from the cnidoblasts or cnidocytes that contain the stinging capsules or nematocysts which present on the tentacles and the body.
Cnidocytes are used for anchoring, defense, and prey capture.
Coelenterata are diploblastic.
The circulatory system is absent.
They have a single opening, hypostome, in their central gastro-vascular cavity.
They do not have sensory organs.
Digestion takes place extracellular and intracellular.
Some cnidarians, such as corals, have a calcium carbonate skeleton.
Polyps and medusas are the two basic body forms of cnidarians. Where asexual reproduction is seen in polyps through budding and sexual reproduction is seen in medusa through gamete. For example Obelia.
Examples of Coelenterata are Physalia (Portuguese man-of-war), Adamsia (Sea anemone), Pennatula (Sea-pen), Gorgonia (Sea-fan), and Meandrina (Brain coral).
Fig:- Aurelia (JellyFish)
Classification of Phylum Coelenterata are as follows:-