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