1 Cell to Urchin
© 1998 Chris Patton, Stanford University

This animation traces the development of the sea urchin from

the single fertilized cell to
the baby sea urchin.

Some of the steps along the way:

At the forth division the micromeres form
The swimming blastula "hatches"
Gastrulation forms the mouth from the anus
Prism stage. Embryo starts to feed
Early Pluteus, about 3 days from start
Late Pluteus, about one week
Metamorphosis happens at several months
Producing the baby sea urchin