Steven Spielberg passed on directing this third installment in the series based on Michael Crichton’s book, and it was a wise decision on his part. “Jurassic Park III” proves that the franchise has run out of gas. The same thing had happened to another Spielberg-started succession of flicks by the time that “Jaws 3-D” came along in 1983, and while the new “Park” isn’t that dreadful, its dinosaur-based hokum now seems as antediluvian as the leviathans who populate many of its scenes; the musty odor of a fossil hangs over the whole enterprise. Not even the return of Sam Neill, who starred in the original but largely went AWOL the second time around, can do much to revivify this sad old heap of bones. It’s pleasant to note that the flick is less than three-quarters the length of the first two, but that’s hardly enough to make it worthwhile.

Typical of how the mighty have fallen is the fact that the helming duties have been transferred to Joe Johnston, a mediocre journeyman whose previous masterpieces were “Honey, I Shrunk the Kids,” “The Rocketeer” and “Jumanji.” (He also made the sweet “October Sky,” but it now appears that was just an aberration in a string of bloated special-effects monstrosities.) Johnston brings his singularly unmagical touch to the picture, which basically recycles the small-group-of-people-in-jeopardy shtick of the first two movies to rapidly diminishing returns. This time around the endangered humans are a divorced couple, Paul and Amanda Kirby (William H. Macy and Tea Leoni), who con old our friend Dr. Alan Grant (Neill) and his eager assistant Billy (Alessandro Nivola) to accompany them to John Hammond’s quarantined Dinosaur Island; their goal, at first kept from Alan and Billy, is to find their teenaged son Eric (Trevor Morgan, an obvious sop to the kiddie crowd at which the project is aimed), who disappeared while hang-gliding in the vicinity with Amanda’s boyfriend. Before long, of course, they’re all acting extremely stupidly in the face of the mortal danger posed by the various recreated beasts; other humans are involved too, some for comedy relief (a dour, deadpan pilot played by fluttery Michael Jeter) and others to act as little more than lumps of prospective Dino-Chow.

It goes without saying that the effects in the movie are state-of-the-art stuff provided by Industrial Light and Magic, but they’re deployed to remarkably little effect in a script that’s surprisingly flat and uninspired given that one of its three creators is the talented Alexander Payne (of “Citizen Ruth” and “Election” fame). He’s not the only participant slumming here. Macy is usually found in far meatier fare. But we shouldn’t berate him too much: his fat paycheck will probably allow him to appear in ten or more interesting independent pictures like “Fargo,” “State and Main” or “Panic.” And Neill can be forgiven after his nice turn in the recent “The Dish.” But one expects no better from Leoni; after all, she’s wasted our time before in “Deep Impact” and “The Family Man.” The rest of the cast is, unhappily, pretty disposable, and many of them, in fact, are disposed of quickly.

As telling as Spielberg’s absence from “Jurassic Park III” is the fact that though John Williams’ original themes from the first two installments are recycled in the picture’s score, the new music has been composed by Don Davis, and it’s as anonymous as Johnston’s direction. Richard Attenborough is also missing from the picture. Maybe he’s smarter than his own dully high- minded pictures (“Gandhi,” “Cry Freedom”) would suggest. But even his avuncular presence couldn’t have helped this thoroughly unnecessary sequel. The movie’s almost silly and turgid enough to make one wish that at the end another giant meteor had struck the earth and finally rendered these increasingly dull creatures extinct once more–or at least the sort of imbecilic specimens of homo sapiens that populate such pictures as this. In keeping with what’s becoming the obligatory leitmotif of Hollywood movies nowadays, by the way, “Jurassic Park III” introduces us to T-Rex pee and Spinosaurus doo-doo. I’ll bet you can hardly wait.