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