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