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