Pro Patria presentation. Produced by British Instructional Films Ltd.

The busy sea bed is compared to a traffic system with jams and crashes. Sailing boat on the sea. Underwater shots of fish. Many fish moving around together. Voice over calls for a "one way system" to avoid pile ups. Strange sea creatures. Starfish moving around on the sea bed. Starfish sinking into the ground to avoid being seen - "don't you sometimes wish you could do the same?" Masked (?) crab burrows into the sand leaving its long feelers sticking out. A strange fish with legs. Cuttle fish and its frilly fin. Crawfish meandering around the sea bed. Lobster blunders in and out of the rocks. Lobsters escape predators. Prawns and shrimps have instantaneous reverse motion. Crabs walking sideways. Hermit crabs - "owner drivers in baby cars." Spider crab in C/U. A "fight" between two spider crabs. A sea plant opens up its petals. Whelks. Scallop opening and closing is compared to a sneeze. Mussels on the back of a scallop shell, the scallop is overbalanced by the mussels. Starfish stalks its prey - eventually getting on top of the scallop shell. The crabs finish what the "greedy starfish" doesn't eat. "The sea swarms with other murderers intent on robbery with violence..." including the ravenous conger eel. "The sea cucumber looks like a harmless pin cushion..." but produces a firework effect of touch sticky threads if frightened or pinched (a hand in the tank prodding the cucumber is just visible). A crab in a hurry gets entangled in the threads. A lobster gets held up too. A smaller crab gets caught and struggles until he has no life left. Voice over says: "and with his last kick, there ends another of those traffic fatalities which are forever occurring beneath the surface of the sea..." Portentous music over shot of the sun setting over the sea.

Note: multiple prints and negs exist. German and French tracks exist.