echinodermata

• from Greek ekhinos ‘hedgehog, sea urchin’ + derma ‘skin’
• . 3. 4. 5. 6. 7. Living in marine habitats Adults with pentaradial symmetry and larva with bilateral symmetry.
• . Deuterostomes and Body unsegmented (nonmetameric).
• Endoskeleton of dermal calcareous ossicles with spines or of calcareous spicules in dermis.
• Triploblastic Body.
• unique water-vascular system. It is used for locomotion, food and waste transportation, and respiration. The system is composed of canals connecting numerous tube feet.
• Nervous system with circumoral ring and radial nerves; No brain.
• Complete digestive system
• Autotomy and regeneration of lost parts conspicuous; asexual reproduction by fragmentation in some.
• Dioecious, sexes are separate (except a few hermaphroditic
• Class Crinoidea

  
• Class Asteroidea

  
• Class Echinoidea

  urchins
• Class Holothuroidea