Larval forms of sponges include
Poriferan free-swimming larvae include amphiblastula hollow blastula with anterior hemisphere flagellated smaller micromeres and posterior hemisphere larger unflagellated macromeres characteristic of calcareous syconoid sponges, after inversion settles and flagellated cells become choanocytes. Parenchymella also called parenchymula or stereogastrula typical of demosponges solid structure with outer flagellated columnar epithelium surrounding inner mass of amoeboid cells. Both lecithotrophic planktonic dispersal forms. Planula belongs to cnidarians, trochophore to lophotrochozoans, veliger moll
Ref: Brusca & Brusca Invertebrates 3rd ed. Porifera Larvae; NCERT Class 11 Chapter 4 Larval Forms
