• Amphiblastula larva occurs in the development of most of the calcarea.
• Stomoblastula stage undergoes a process of inversion .During this process, the
flagellar ends of micromeres come outside and then it is called Amphiblastula larva.
It is free swimming larva. It is
more or less oval shape and consists of one
half of small narrow flagellated micromeres
and the other half of large rounded granular
cells or non flagellated macromeres
• A fully elope amphiblastula
first comes in mradial canal and then passes

to exterior through osculum and then leads.
granular cells
a free swimming life

• This larva leads to a free swimming life

for some time during which gastrulation

takes place by the invagination of the
flagellated cells

. Gastrula soon attaches itself to some rock e sea weed by its blastoporal end and
develops a central spongocoel and an osculum
Non flagellated cells form the dermal covering and the flagellated cells become
the choanocytes lining the spongocoel. Later larva developds into a younger sponge

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