bond thought of what was going on in the hundreds of fathoms below the boat , the big fish , the shark and barracuda and tarpon and sailfish quietly cruising , the shoals of kingfish and mackerel and bonito and , far below in the grey twilight of the great depths , the phosphorous jellied boneless things that were never seen , the fifty-foot squids , with eyes a foot wide , that streamed along like zeppelins , the last real monsters of the sea , whose size was only known from the fragments found inside whales .