This is a piece from a cartoon show that will probably never see the light of day on DVD or any other home video format, Linus The Lionhearted. The show ran on CBS on Saturday morning in the 1960's and starred several characters who all started out as trademark symbols for various Post cereals. There was Linus, a lion who ruled a jungle (the star for Crispy Critters cereal), Lovable Truly, a mailman (Alpha-Bits), Sugar Bear (Sugar Crisps) and So Hi, a little Chinese boy (Rice Krinkles). It's certainly not unusual for cereals to have cartoon spokesmen in commercials like the Trix rabbit, Captain Crunch and Quake and Quisp but this is the only time I know of where those characters were put into full length cartoons.
The cartoons weren't bad and deserve to be remembered as more than just extended commercials. The animation was good, the stories, like this Linus example, tended to have an adult level of humor as well as the kiddie stuff and the voice talent included some well known actors who were associated with some of the prime time CBS shows Post sponsored like "The Dick Van Dyke Show" and "The Andy Griffith Show". Sheldon Leonard and Carl Reiner are doing the voices here and I remember Howard Morris and Jonathan Winters doing voices in some of the other cartoons.
Obviously the commercial ties of these cartoons make them verboten for release today even though I don't think Post even makes most of those cereals any more so this is a real rarity. Here is Linus The Lionhearted in "Travel Is Broadening".