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