pty. When carrying a spear gun or his
camera, he also swam with arms hanging downward. Neither boy used his
arms for swimming. The rhythmic, powerful leg strokes were enough,
thanks to the swim fins.

The water deepened rapidly but lost none of its clarity. Even at a depth
of a dozen feet, Rick thought, he could have counted every grain of
sand. This was unlike anything he had ever experienced. At home,
visibility of five feet was considered good. Lost in the enjoyment of
really clear water, he completely forgot about the shadow.

Scotty reminded him. He touched Rick's arm and signaled a stop. The boys
removed their snorkel mouthpieces and faced each other upright in the
water, holding position with easy flipper movements.

"Just pretend we're talking," Scotty said. "Don't look around. I'm
trying to spot our friend over your shoulder." After a moment he shook
his head. "No sign. Wonder if he ran for a bathing suit?"

"Forget him. Let's swim. See any coral heads?"

"Darker water off yonder. Let's look."

They readjusted their snorkels and headed in the direction Scotty had
indicated.

Rick breathed easily through his tube, constantly scanning the bottom.
Now and then he saw various kinds of debris on the bottom, including
abandoned beer cans and a section of newspaper that had not yet rotted
away. Rubbish like this was to be expected in a harbor, he supposed,
still it was as unattractive to a swimmer as junk along the roadside is
to the motorist.

Suddenly he noticed a fish--the first he had seen. He took a deep breath
and dove by letting his head drop and then lifting his legs to a nearly
vertical position. He slid underwater without a splash. When his fins
were below the surface he started his leg motion again, and the flippers
propelled him smoothly downward.

The fish was perhaps a foot long, silvery, with a pointed nose and
yellow fins. Rick couldn't identify it. The fish was busily rooting in
the sand for morsels of food and paid no attention to the diver until
Rick reached out and almost touched it, then it sped just beyond reach
and commenced rooting again.

His curiosity satisfied for the moment, Rick surfaced and rejoined
Scotty. As he took position at his friend's side, the other boy hooted
once, their signal for "attention." The hooting was done by making a
kind of "hooty" groan into the snorkel mouthpiece, about the only sound
that could be made without letting water pass the lips. Because water