Sing, You Sinners (1938)

Of the singing Beebe brothers, young Mike just wants to be a kid; responsible Dave wants to work in his garage and marry Martha; but reckless Joe thinks his only road to success is through swapping and gambling. It seems the only thing all three can join in is their singing act, which Mike and Dave hate. Finally, all Joe's hopes are pinned on a race horse he's acquired, but it's a bigger gamble than his family knows. Hilarious sequence involving a lecturer on seals.