‘Turtles’ Take: $50.9 Million in Two Weeks : Box office: The kids movie featuring the wise-cracking quartet of terrapins is close to setting a record for an independent film.

The radioactive reptiles did it again. New Line Cinema’s “Teenage Mutant Ninja Turtles” snapped up $18.8 million in ticket sales during their second week at the box office--bringing grosses to a shell-shocking $50.9 million.

In release at 2,226 screens, the Turtles commanded a startling $8,452-per-screen. It’s an assault that’s expected to continue this week, since many youngsters are currently on spring break.

Spawned by a 1984 comic book, the man-size, pizza-crazy Turtles--who star in a popular cartoon series--are now poised to ax Freddy Krueger’s record and emerge as New Line’s top-grossing film. Up until now, the fourth film in the “A Nightmare on Elm Street,” series--1988’s “A Nightmare on Elm Street 4: The Dream Master”--was New Line’s No. 1 movie, with receipts of $50 million.

The Turtles will also doubtless wax another record--to become the top-grossing independently released film. The honor currently goes to Vestron’s “Dirty Dancing,” which earned $54 million in 1987.

Turtlemania wasn’t the only big news at the box office.

“Pretty Woman,” from Disney’s Touchstone Pictures, earned $11.2 million, for yet another week in the No. 2 spot. Starring Richard Gere as a corporate executive who falls in love with Hollywood hooker-turned-lady Julia Roberts, the Pygmalionish comedy-romance has $44.2 million, after just three weeks.

Disney’s Touchstone also claimed the No. 3 spot, with the third installment in the film series about dumb-guy hero Ernest P. Worrell, as played by Jim Varney. “Ernest Goes to Jail” locked up ticket sales of $6.1 million.

In No. 4 was Orion Pictures’ supernatural thriller, “The First Power,” with receipts of $5.6 million.

Fifth place went to Paramount Pictures’ still-formidable “The Hunt for Red October,” which torpedoed about $5 million in ticket sales, for cumulative grosses of $83.5 million.

Among the weekend disappointments were several new releases, including: Tri-Star’s “I Love You to Death,” which boasted an all-star cast and direction by Lawrence Kasdan but managed only $4 million, for sixth place.

Universal’s “Cry Baby,” starring heartthrob Johnny Depp, with direction by cult king John Waters, did only $3 million. In limited release at 155 screens, the Warner Bros.’ thriller, “Impulse,” had receipts of $471,126.

Meanwhile, Universal’s “Opportunity Knocks,” starring “Saturday Night Live’s” Dana Carvey, plummeted an estimated 39% its second week, for receipts of $2 million and grosses of $6 million.