Phylum Echinodermata
Habit and habitat: All members of this phylum are marines. None occurs on land or fresh water. Different species of Echinodermata are found in all seas of the world. Majority of them are free living, but some are at the adult stage lead a stationary life. The Echinodermata, (from the Greek meaning spiny skin), is a phylum containing some 13,000 extinct and 7,000 extant species. Living representatives are only found in marine environment, making the phylum the largest lacking terrestrial and fresh water forms.
Identifying characters:
- Integument spinous
- Body radially symmetrical or can be divided into five similar parts
- Water vascular system controls the locomotion and respiration
- In adult animal, head, dorsal and ventral side is not marked clear, oral and aboral surfaces are present.
Example: Asterias rubens (Star fish) Echinus esculentus (Sea urchins).
