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