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