the fear that the submarine cannot survive such depths. In order to prove this, he locks the engine room door and sends the sub into a fatal dive. As soon as this crisis is averted, Unga Khan and Captain Hakur detect their approach and bring them through a tunnel into the Inland Sea with a Magnetic Ray. Cast Main cast Ray "Crash" Corrigan as Crash Corrigan, Athlete and Navy Lieutenant. Crash Corrigan's stage name came from this serial. Lois Wilde as Diana Compton, Reporter from the Times who joins the expedition to Atlantis to get a story Monte Blue as Unga Khan, Tyrant and leader of the Black Robes William Farnum as Sharad, High priest of Atlantis and leader of the White Robes Boothe Howard as Ditmar, one of Unga Khan's Black Robes Raymond Hatton as Gasspom, one of Unga Khan's Black Robes C. Montague Shaw as Professor Norton, a British-born US scientist and leader of the expedition to Atlantis in his Rocket Submarine Lee Van Atta as Billy Norton, Professor Norton's young son who stows away aboard the submarine expedition Smiley Burnette as Briny Deep, a sailor in Professor Norton's Rocket Sub expedition and comic relief Frankie Marvin as Salty, a sailor in Professor Norton's Rocket Sub expedition and comic relief Supporting cast Lon Chaney, Jr. as Captain Hakur, Black Robe commander, Unga Khan's main henchman. Captain Hakur was "probably" Lon Chaney, Jr.'s "most colourful henchman." Lane Chandler as Darius, one of Sharad's White Robes Jack Mulhall as Lieutenant Andrews, US Navy John Bradford as Joe, a sailor in Professor Norton's Rocket Sub expedition who goes mad with fear and almost kills them all Malcolm McGregor as Zogg, one of Unga Khan's Black Robes Ralph Holmes as Martos, one of Sharad's White Robes John Merton as Moloch, Black Robe whose life is spared by Corrigan and switches sides Ernie Smith as Gourk, one of Unga Khan's Black Robes Lloyd Whitlock as Captain Clinton, US Navy Captain Production Undersea Kingdom was budgeted at $81,924 although the final negative cost was $99,222 (a $17,298, or 21.1%, overspend). It has the lowest budget of any Republic serial but it was only the third cheapest in actual production cost. The serial was filmed between 3 March and 28 March 1936 under production number 417. The only cheaper serials were the subsequent The Vigilantes Are Coming ($87,655) and, in 1938, The Fighting Devil Dogs