Purple Sea Urchin
Arbacia punctulata
Size: to 3"
Sea Urchins may be found on any solid structure, from tidal rocks to deep wrecks, although in our region they are more common in shallow estuarine waters than offshore.
This animal is related to the starfish, and shares many of its traits, with one exception. Starfish are predators, feeding upon clams and mussels, while these sea urchins are strict vegetarians. I once ordered Sea Urchin at a sushi bar, but I never even tasted it, it smelled so bad. Nonetheless, it is a delicacy in much of the far east. Unlike tropical black urchins, our northern ones are not poisonous, and the spines are not even particularly sharp.
Echinoderms ( literally "spiny skins" ) are among the strangest animals on the planet. They start out as bilaterally symmetric larvae but grow into a 5-way body symmetry as adults. Some species show six, seven, or even higher levels of symmetry. Worm-like Sea Cucumbers have re-evolved a bilateral body plan over the underlying 5-way plan. Because of certain developmental traits, it is felt that despite their strangeness, echinoderms are actually more closely related to chordates than any other group.
More: Echinoderms ...