Notes from NEET topper
Phylum- Echinodermata (Spiny-bodied)
• Habitat-all marine.
• Endoskeleton-Calcareous ossicles.Show retrogressive metamorphism (larvae is bilateralsymmetrical but adult is radial).
• Digestive system-complete with mouth on ventral/ lower& anus on dorsal/ upper side.
• Water vascular system-help in locomotion, capture &transport of food, respiration.
• Excretory system-absent Reproduction-dioecious.
• Fertilisation-usually external with indirect development(free swimming larvae).
• Eg- Asterias (starfish),Echinus(sea urchin), Antedon(sealily),Cucumaria (sea cucumber) &Ophiura (brittle star).
