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Date & Time : 28, December 2024 01:00
Pedicellaria of Star fish
- They are modified spine like structures, scattered all over the body.
- Types : two types,straight type and crossed type.
- Composition : consists of basillar plates and two valves.
- Valves : movably articluated with basilar piece.
- Muscles : adductor(2 pair) and abductor(1 pair) muscles present.
- Function : Offence and defence.
Bipinnaria larva
- characteristic free swimming larva of Asteroidea.
- Developmental changes : develops three lateral lobes on each side within 2-7 days.
- Anterior end : consists of dorso-median arm,ventro-median arm and pre-oral arms.
- Lateral sides : consists of antero-dorsal arms,postero-dorsal arms,post-oral arms and postero-lateral arms.
- Alimentary canal : has mouth,oesophagus,stomach,intestine and anus.
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