The "A Stinging Experience" Story

It was an ordinary day.  Sitting in my beach chair hoping the pain in my foot will subside sooner rather than later.  Carol and I were snorkeling off the coast of Pinel Island when I inadvertently tramped on a sea urchin.  You know, the round black thing with all the sharp spines that stick out all around it.  Hurt?  Felt like someone had stuck hundreds of needles in my foot at the same time, only this pain didn't let up after a few seconds.  The only lucky part of the experience was that none of the spines had stuck in my foot.  

Some of the sea urchins we have collected.
The smallest one is about the size of a quarter.

I hobbled out of the water and headed towards a couple of guys that ran the snorkeling station.  They saw me coming and knew exactly what I had done.  And their response was to go sit in my beach chair for about an hour or two until the pain went away.  So, that's why I'm sitting in my chair at present.  For years, Carol and I have seen these prickly creatures on the ocean bottom and often wondered what good they did and what it would feel like if you touched one.  I now know!  The sea urchin, also known as an echinoderm, appeared on the earth around 500 million years ago.  When you see it on the ocean bottom it looks menacing and you can't see movement, but the spines attach to ball-and-socket joints on the shell and can point in any direction.  When I tramped on it I elicited a prompt reaction from the spines which converged toward the place that I touched so more than one spine probably got me.  

The sea urchin as seen from the bottom.

The urchin has no visible eyes, legs or means of propulsion, but can move freely over the bottom using adhesive tube feet that work in conjunction with the spines.  They feed mainly on algae, but can feed on sea cucumbers, a wide variety of invertebrates such as mussels and the occasional swimmer.  More are found in shallow areas than on the deep ocean floor.  Their mouth is made up of five calcium carbonate teeth or jaws with a fleshy tongue-like structure within.  The entire chewing organ is known as Aristotle's lantern derived from Aristotle's description in his History of Animals. The teeth are self-sharpening and can chew through stone.  

The teeth structure is shown next to the shell.

The sea urchin has five pairs of external gills, located around their mouth which is on the bottom of the urchin.  They are sensitive to light, touch and chemicals even though they have no eyes.  For those of you who have collected a sand dollar or sea biscuit, they too are members of the echinoderm family.  When the sea urchin dies and all the spines have been removed from the shell, it is a beautiful specimen.  

Other varieties of the echinoderm family.  On the
left is the sea biscuit while on the right is the sand dollar

Carol and I have a special location on St. Martin where we go every vacation to see if we can find any dead echino- derms.  Over the years we have collected a couple dozen of the urchin, star fish and sea biscuit varieties.  Hardest part of the collection process of the sea urchin is removing the spines, if they haven't already fallen off the shell and the transportation of our find to Lancaster.  They are so brittle and the shell is so thin that we have broken over half of our finds.  But, I keep telling her that the end result isn't half as much fun as the search.  After all, we have to be on an ocean beach in order to find them in the first place.  It was another extraordinary day in the life of an ordinary guy.