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