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