Sea cucumbers
Small fish
Other sea urchins
Algae
Mouth
Spine
Nose
Feet
Toothpick
Porcupine
Pentamerous
Dome
Animalia
Purpuratus
Echinoderms
Strongylocentrotus
On the beach
Intertidal area only
Both intertidal area and subtidal areas
Subtidal area only
Because sea urchins have large numbers of eggs
Because a sea urchin's egg is relatively big
Because the eggs make great omlettes
Because sea urchins have large numbers of relatively big eggs