What instrument is this?

I was watching “The Andy Griiffith Show” tonight. It was the episode called “The Darling Baby.” In the episode, the "Darlings’ perform with one of the men playing a instrument that resembled a violin in appearance, but he was playing as if it were a small guitar. If anyone is familiar with the episode or the instrument description, was it a violin and, if not, what instrument was it?

Maybe a mandolin? It’s a popular instrument in old-time country and folk music.

Possibly a mandolin?

Could it have been a fiddle that was being plucked by finger?

The only other thing I can think of would be a mandolin. I’ve never seen one shaped like a fiddle, but it would be similar in size.

Googling around, it looks like the Darlings were, in fact, The Dillards, whose instruments were guitar, double bass, banjo, and mandolin. So I assume you were seeing the latter.