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