In my posts over the last week, whatever I'm talking about, the sea urchins manage to worm their way in. They're mostly green sea urchins, although a red and a purple have shown up on the beauty bush.
Time to give them the spotlight they're begging for.
Green sea urchins, Strongylocentrotus droebachiensis, are small and gregarious. They are usually mostly green, with darker lines on the test (the round shell). Sometimes they're purplish.
Purple sea urchins, Strongylocentrotus purpuratus, are larger; their spines are green as juveniles, changing to pink, red, and purple as they mature.
Red sea urchins, Strongylocentrotus franciscanus, are the largest. They may be red, purple, pinkish, or even purple-black.
|A green sea urchin on beauty bush. The test is up to about 9 cm. (2 - 3.5 inches) across.The spines are short and pale green.|
|The green sea urchin turned over. The central part is the mouth, with the plates that serve as teeth, called "Aristotle's lantern". More on these, later.|
|A purple sea urchin. This specimen measures 11 cm. across, spines and all.|
The purple sea urchin's test may grow to 10 cm. (4 in.), and the spines are relatively short, usually under 2.5 cm. (1 inch) long.
|And a red sea urchin.|
The reds grow up to 30 cm, (12 inches) across, counting the spines, which account for half the width.