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