Slides over sand upon its broad flat side,
And twists its head until its nether eye
Looks upward, too, and what swam upright once
Is fixed in its new shape, and the wry mouth
Grimaces like a gnome at its old foes.
He saw the swarming mackerel shoals that swim
Near the crisp surface, rippled with blue and green
Round their dark backs to trick the pouncing gull,
But silver-bellied to flash like streaks of light
Over the ravenous mouths that from below