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