Which cartoon duo were originally called Jasper and Jinx?

'Tom and Jerry' is an American animated franchise and series of comedy short films created in 1940 by William Hanna and Joseph Barbera. Best known for its 161 theatrical short films by Metro-Goldwyn-Mayer, the series centers on the rivalry between the titular characters of a cat named Tom and a mouse named Jerry.

In its original run, Hanna and Barbera produced 114 'Tom and Jerry' shorts for MGM from 1940 to 1958. During this time, they won seven Academy Awards for Animated Short Film. After the MGM cartoon studio closed in 1957, MGM revived the series with Gene Deitch directing an additional 13 Tom and Jerry shorts for Rembrandt Films from 1961 to 1962. Tom and Jerry then became the highest-grossing animated short film series of that time, overtaking 'Looney Tunes'.

The series features comic fights between an iconic pair of adversaries, a house cat (Tom) and a mouse (Jerry). The plots of each short usually center on Tom and Jerry's numerous attempts to have the best of each other and the mayhem and destruction that follows.

Tom (named "Jasper" in his debut appearance) is a gray and white mute domestic shorthair cat. He is usually but not always, portrayed as living a comfortable, or even pampered life, while Jerry (named "Jinx" in his debut appearance) is a small, brown mute, house mouse who always lives in close proximity to Tom. Despite being very energetic, determined and much larger, Tom is no match for Jerry's wits.