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