The main characteristics of cnidaria

Previously known as Phylum Coelenterata

Habit and habitat

Members of this phylum are present in almost all the regions of the world. They are mostly marine. Many species found in canals, beels, rivers, lakes, fountains, etc. They are diverse in shape, size and colour. Some species live alone (solitary) and some live in groups forming colonies. They attach themselves to floating logs, leaves or other substrate or move freely i.e. free swimming.

General characteristics of cnidaria

1. Body consists of two embryonic layers. The outer one is ectoderm and the inner one is endoderm.
2. Body cavity known as coelenteron. It helps in digestion and circulation.
3. Ectoderm bears a special type of cells called cnidoblast. These cells help in locomotion, defense, capture of prey.

Cnidaria example, The scientific name or binomial nomenclature

• Jellyfish – Aurelia aurita
• Sea anemones – Metridium senil
• Coral – Meandrina meandrites
• Sea pen – Pennatula sulcata
• Hydra – Hydra vulgaris
• Pennatula aculeata
• Gorgonia verrucosa
• Obelia geniculata
• Adamsia palliata
• Porpita sp.
• physalia sp.

Where does come form the name (word) of Cnidaria

The word Cnideria comes from the Greek Knide, meaning hairy, and the Latin Aria, meaning connected.

Reference: NCTB

➤ The main characteristics of Porifera phylum