Paramount Pictures Corp., already the owner of a large chain of Canadian motion picture houses, said yesterday that it has agreed in principle to acquire 24 Trans-Lux theater screens for about $15 million.

The deal signals Paramount's re-entry into U.S. exhibition after a 37-year absence. The company divided its movie-making and exhibition businesses in 1949 when faced with a federal antitrust action. Paramount Pictures, which retained the production unit, was not barred from theater ownership under the consent decree it signed. (Nor were two other major studios, Universal Pictures and Columbia Pictures.)

Trans-Lux Chairman Richard Brandt said the sale includes one New York theater, the Gotham Cinema, which he described as one of Manhattan's eight or 10 "key houses" for opening significant motion pictures. Trans-Lux, which has its headquarters in Norwalk, Conn., has been in the exhibition business since 1931, but derives two-thirds of its revenue from the production of electronic teleprinters and ticker devices for the financial markets.

The sale to Paramount, a Gulf & Western subsidiary, will end Trans-Lux's role as a traditional exhibitor, although it will keep two theme-oriented, multi-media exhibitions in New York City.

Last February, Trans-Lux spent nearly $3 million to repurchase a 9.9 percent stake in the company held by two New York businessmen, Michael Landes and Albert Schwartz, who had said they might seek control of the company. For the year ended Dec. 31, the company reported a net income of $1.7 million on revenue of $30.7 million.

If Paramount completes the acquisition, it will become the fourth movie distributor to invest in the exhibition side of the business in less than a year.

Last month, MCA acquired 50 percent of Cineplex Odeon for about $159 million, and the Cannon Group announced plans to buy Commonwealth Theatres for $24 million.