Jay Ward's next to last creation, Hoppity Hooper, bounded onto Saturday mornings in 1964 on ABC, 4 years after Ward had shopped a pilot to the networks.
The basic plot was similar to the serials over on The Bullwinkle Show (pka Rocky & His Friends), only in this case you had a frog (Hoppity), a fox ("Uncle" Waldo), and a bear (Fillmore), the latter carrying a trumpet, but not that good a player.
When the series went into syndication, for some reason, Uncle Waldo got top billing, as you'll see in the following clip. In fact, that's when I first discovered the series, several years after it'd gone out of production.
When the pilot was recorded in 1960, Alan Reed was the voice of Fillmore, but, as we all know, Reed soon landed the lead in The Flintstones, so Bill Scott, the voice of Bullwinkle, was cast as Fillmore. Hans Conreid (Uncle Waldo) narrates "The Frog Prince of Monomania", uploaded by TootsToons to YouTube:
Regrettably, Hoppity, Waldo, & Fillmore have gone back into limbo, as the series is nowhere to be found these days.