With the retirement of "Murphy Brown," "The Simpsons" is now the longest-running comedy on television. Entering its 10th season, the show is already the longest-running animated series in the history of TV.

But the creation of "Futurama" doesn't mean that "The Simpsons" is going to be retired. At this point, Fox has no such plans. And neither does Groening."I don't know how long `The Simpsons' is going to run," he said. "It's surprised me that it's gone on this long."

But he has a relatively simple theory as to why the show suc-ceeds.

"It's really funny. It really delivers the goods on that level. It's a really funny show," Groening said. "I think the characters are surprisingly likable, given how ugly they are."

And he's not ready to give up on a show that still retains its creative edge.

"I love the show," he said. "This coming season on `The Simpsons' is as good as any we've ever done. Or better."

SNEAK PREVIEWS: Groening briefly recited the plot lines of some of the upcoming episodes of "The Simpsons."

- In one, "keeping a secret proves difficult for Homer when he lands a personal assistant job working for Alec Baldwin and Kim Bassinger."

- In another, Homer becomes obsessed with being like Thomas Edison. "It's a whole show about trying to beat Edison."

- "We have the obligatory Jerry Springer appearance."

- Have you ever wondered what the "J" in Homer J. Simpson stands for? "We finally find out Homer's middle name" in another episode, Groening said. (But he wasn't telling what that name might be.)

- In another episode, Homer "goes to the store and he wants to get lobster. It's too expensive, so he gets a baby lobster to raise it."

- And then there's the episode in which the Simpsons' next-door neighbor, Ned Flanders, has a mid-life crisis. "So Homer takes him to Las Vegas where they take a walk on the wild side, waking up having married two cocktail waitresses the night before."

NO CROSSOVERS: Groening said that none of "The Simpsons" characters will appear on "Futurama" or vice versa. But not because "The Simpsons" is set in the present day and "Futurama" is 1,000 years in the future.

"No, `Futurama' is real. `The Simpsons' are fictional," Groening deadpanned. "However, `The Simpsons' is still on a thousand years from now. With original episodes."

HEADS IN JARS: "The Simpsons" has, over the years, had plenty of big-name celebrities "appear" as themselves - complete with animated overbites. And, despite the 1,000-year time gap, there are apparently going to be big-name celebrities on "Futurama" as well.

"Any celebrity who's big enough we will have on `Futurama' - if you're willing to play yourself as a disembodied head in a jar," Groen-ing said. "We've put the call out. We've gotten some good re-sponse.

"I'm taking the first leap. I am a head in a jar on the first episode."

But he's already had company.

"We also have Leonard Nimoy, and Dick Clark doing `Dick Clark's New Year's Rockin' Eve 3000," Groening said.

RETIRING CHARACTERS? The late Phil Hartman will still be heard on `The Simpsons' doing a number of voices he recorded before his recent death. But once those episodes air, chances are that characters he voiced like Lionel Hutz and Troy McClure will be retired.

"My guess is that none of the writers would be inspired to write for those characters without Phil Hartman doing the voice," Groen-ing said. "Everybody who ever worked with Phil Hartman loved him. I'm no exception."

Hartman was also slated to do a voice on "Futurama." He even offered to come in and read for the part, even though he already had it.

"I said, `You don't have to come in. You got the part. We wrote the character for you,' " Groening said.

But, shortly before his death, Hartman came into the studio and joked and clowned around.

"He was just a good guy. He just really appreciated being there," Groening said. "And, of course, we were shocked and dismayed - as everybody was - that he died.

"Again, I can't imagine us writing for those characters. It's possible. But I don't think so."

ASK A SILLY QUESTION: One critic actually asked Groening if there would be any merchandising to go along with "Futurama."

"Let's see - a show that has ray guns and robots and space ships," he replied. "Yeah, I think there'll be some merchandising.

"We draw the line, though. No Pogs."

Actually, he does no apologizing for the merchandising that has accompanied "The Simpsons."

"I can't imagine doing a cartoon show without thinking about the merchandising," Groening said. "And not for the crass reasons. I mean, I like the money. But, to me, it's just fun. I like the toys. To me, it's part of he whole experience."