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