[QUOTE=Eutychus]
Wow … I wish we had somebody who knew something about classic Disney cartoons around here.
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We’re waiting…
I agree with Rube. I took it to mean silly, consequence-less cartoon violence, not sex, especially given that era.
I’ll look through mine when I get home. Does the story mention that it’s b&w? It sounds like it could be an early Mickey feature. Not Steamboat Willie or Plane Crazy but something along those lines.
[QUOTE=Alive At Both Ends]
The Clarke story contains the following sentence in its description of the cartoon:
To me this sounds like a sex scene (the “slightly different” is a bit of a giveaway). And since Disney films in 1949 didn’t do sex, it’s clear to me that Clarke had no specific film in mind. Could it be that he was predicting a future society in which attitudes to sex had loosened to the extent that it even got into Disney cartoons? Or do I just have an over-active imagination? 
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Unless it was Mickey and Donald or Goofy or Pete.
I agree with those who are saying it’s not a specific cartoon being referenced. It’s just supposed to be a typical Disney cartoon from the 1930’s or 40’s. In particular, I think it’s one featuring Donald Duck since he best fits the description of a “little biped” who has a “characteristic expression of arrogant bad temper.” The story is a set-up to a joke with the punchline being the future Venusians believing that the Disney cartoons are accurate depictions of what civilization on Earth was like.
It’s too bad Clarke did reference a Warner Brothers cartoon. He could’ve then had the Venusians thinking that on Earth it was possible for lifeforms to defy the laws of gravity until they were unwise enough to look down. 
Having been through almost the entire Mickey series this afternoon, I don’t find much to match.
However, the beginning that Clarke describes is remarkably similar to the beginning of the 1927 short “Trolley Troubles” which starred Oswald, the Lucky Rabbit. The short does begin with a crowd scene which eventually focuses in on Oswald. It also has what could be seen as a violent run in with a cow on the tracks and the trolley does take a rather fantastic trip through the country. He does misremember the ending; in Trolley, Oswald doesn’t end up in a city, but with his trolley submerged and him swimming behind to catch it. And there is no head-on collision.
Also, this being before Disney did his own distribution, the end wouldn’t have said “A Walt Disney Production” but “An M. J. Winkler Production.” But I think the description is close enough that this one is at least the one the that Clarke was wrongly remembering.