Algae
Small fish
Other sea urchins
Sea cucumbers
Strongylocentrotus
Purpuratus
Animalia
Echinoderms
Both intertidal area and subtidal areas
Subtidal area only
On the beach
Intertidal area only
Spine
Feet
Nose
Mouth
Pentamerous
Porcupine
Toothpick
Dome
Because sea urchins have large numbers of relatively big eggs
Because the eggs make great omlettes
Because a sea urchin's egg is relatively big
Because sea urchins have large numbers of eggs