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