[B] Cephalochordata

• Basic body plan of cephalochordates are dorsoventrally inverted compared to earlier deuterostomes
• In hemichordates, pharyngeal slits open dorsally

  In chordates, they open ventrally
• Buccal cirri

  • Functions as a sieve, blocks large particles
• Wheel organ

  • With ciliated tracts sweeping food into the mouth 
• Hatschek's pit

  • Secretes mucus to collect food