Waters of the world, 21 letters
Bay, for instance?, 10 letters
The Bermuda Triangle, e.g.?, 10 letters
Cecil of cartoons, e.g., 10 letters
Hydra, astronomically, 10 letters
Imaginary snakelike swimmer, 10 letters
Legendary denizen of the deep, 10 letters
Mysterious swimmer, 10 letters
Mythological swimmer, 10 letters
What the constellation Hydra represents, 10 letters