Phylum Echinodermata

• All the members are marine, live mainly on the ocean floor.
• These animals have an endoskeleton of calcareous ossicles, and hence the name echinodermata (spiny bodied).
• Level of organization - Organ-system level of organization.
• Body symmetry - The adults are radially symmetrical, but the larvae are bilaterally symmetrical.
• Body wall - Triploblastic. Coelomate animals.
• Digestive system is complete.
• The mouth is present on the ventral side and anus on the dorsal side.
• The most distinctive feature is the water vascular system.
• This helps in locomotion, capture and transport of food and respiration.
• Excretory system is absent.
• Sexes are separate.
• Reproduction is by sexual means.
• Fertilization is usually external.
• Development is indirect with free-swimming larva.
• Example: Star fish, Sea urchin, Brittle star.
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