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