n find out about Niobe's oceans, there is virtually no acceptable
food for starfish other than oysters and some microscopic animal life
that wouldn't sustain an adult."

"Okay, I believe you. But you still leave me cold. I can't remember
anything about a starfish that would help him break an oyster shell."

Bergdorf grinned. "I see you need a course in marine biology. Here's a
thumbnail sketch. First, let's take the oyster. He has a big muscle
called an adductor that closes his shell. For a while he can exert a
terrific pull, but a steady tension of about nine hundred grams tires
him out after an hour or so. Then the muscle relaxes and the shell gapes
open. Now the starfish can exert about thirteen hundred grams of tension
with his sucker-like tube feet, and since he has so many of them he
doesn't have to use them all at one time. So, by shifting feet as they
get tired, he can exert this pull indefinitely.

"The starfish climbs up on the oyster shell, attaches a few dozen tube
feet to the outside of each valve and starts to pull. After a while the
oyster gets tired, the shell opens up, and the starfish pushes its
stomach out through its mouth opening, wraps the stomach around the soft
parts of the oyster and digests it right in the shell!"

I shuddered.

"Gruesome, isn't it?" Bergdorf asked happily. "But it's nothing to worry
about. Starfish have been eating oysters on the half shell for millions
of years. In fact I'll bet that a starfish eats more oysters in its
lifetime than does the most confirmed oyster-addict."

"It's not the fact that they eat them," I said feebly. "It's the way
they do it. It makes me ill!"

"Why should it? After all a starfish and a human being have a lot in
common. Like them, you have eaten oysters on the half shell, and they're
usually alive when you gulp them down. I can't see where our digestive
juices are any easier on the oyster than those of a starfish."

"Remind me never to eat another raw oyster," I said. "On second thought
you won't have to. You've ruined my appetite for them forever."

Bergdorf chuckled.

"Well, now that you've disposed of one of my eating habits," I said
bitterly, "let's get back to the problem. I presume that you'll have to
find where the oysters are before you start in working them over with
starfish."

"You've hit the reason why I'm here. That's the big problem. I want to
find their source."

"Don't you know?"

"I can make a pretty good guess. You