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