Underwater photography, magnified close-ups, and film through microscope present the sea urchin, a complex creature. We see their mouth and five teeth close and open. After injecting one with gelatin, the shell is removed and we see the muscle structure, digestive tube, and reproductive organs. Magnified stems reveal suction cups; stems lengthen and contract allowing the sea urchin to move. We see microscopic calcareous stems; at their ends are jaws with various uses. Cilia everywhere are in constant motion, stirring up water and debris. African music on the soundtrack suggests a shuffle dance.
| Directing | Jean Painlevé | Director |
| Directing | Geneviève Hamon | Director |
| Crew | Claude Beausoleil | Cinematography |