New shows for kids -- ''CRO,'' ''Citykids,'' and ''Tales From the Cryptkeeper'' are a few new shows debuting this fall

On Saturdays, ABC unveils CRO (8-8:30 a.m.; premieres Sept. 18), a cartoon about a Cro-Magnon boy who applies scientific principles in the Ice Age, and CityKids (11:30-noon; premieres Sept. 18), a gritty, dramatic, fast-paced Jim Henson production featuring fast-talking teens and funky Muppets. Tales From the Cryptkeeper (10-10:30 a.m.; premieres Sept. 18) is the network’s animated, junior version of the adult HBO anthology series. The video game Sonic The Hedgehog also becomes an ABC cartoon (9-9:30 a.m.; premieres Sept. 18), with Family Matters‘ Jaleel White as the voice of Sonic. Let’s just hope the hedgehog doesn’t have Urkel’s dance moves.

Lured by CBS, Die Hard screenwriter Steven De Souza adapted the comic-book series Xenozoic Tales into Cadillacs and Dinosaurs (11:30 a.m.-noon; premieres Sept. 18), a futuristic cartoon with humans observing prehistoric life from an armored Cadillac. CBS also acquires the acclaimed, formerly syndicated science show Beakman’s World (12-12:30 p.m.; premieres Sept. 18).

NBC’s Saturday lineup is anchored by Saved by the Bell: The New Class (11-11:30 a.m.), a sequel to the Bell that has moved to prime time. New Class is followed by a boarding-school variation on Bell, Running the Halls (11:30 a.m.-noon).

Fox tackles the weekdays with hyper ‘toons running amok in Steven Spielberg Presents Animaniacs (4-4:30 p.m.)-finally, something Spielberg’s kids can watch. Mornings bring Mighty Morphin Power Rangers (7:30-8 a.m.), a live-action series about high-kicking teens who ”morph” into martial artists. Not to be confused in any way with Teenage Mutant Ninja Turtles, of course.

Don’t look now, Beakman, but there’s another stand-up comic-scientist in the lab — the syndicated Bill Nye the Science Guy (check local listings for days and times). His experiments are funded (and presented) by Disney.

Finally, more female Muppets will join the gem of kids’ programming, Sesame Street (check local listings for days and times), which turns 25 this year.