To the extent that anyone under 40 knows of Fritz, it's probably as a mere cartoon sex romp. So it may be a surprise to learn that, under the direction of animator Ralph Bakshi, it's really a groovy satirical document. Released at the height of the Nixon era, ''Fritz'' spoke to a counterculture fed up with '60s idealism. The film's titular feline -- who, along with the rest of its menagerie of characters, first appeared in R. Crumb's subversive comics -- is an NYU student who sets off on a Homeric journey through the blighted New York City night. Originally on a quest for revolution, Fritz discovers, through a series of disillusioning encounters with hippies, Black Panthers, bikers, and dopers, that he'll settle for discovering the meaning of life. Unfortunately, what made ''Fritz'' so insightful then makes it look like a frozen-in-time artifact now, but at least it's a randy, articulate, occasionally funny one.