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