Nose
Feet
Mouth
Spine
Purpuratus
Strongylocentrotus
Echinoderms
Animalia
Porcupine
Pentamerous
Toothpick
Dome
Sea cucumbers
Other sea urchins
Small fish
Algae
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
Intertidal area only
Both intertidal area and subtidal areas
On the beach
Subtidal area only