at least I think they are by Mel. http://www.animationarchive.org/2006/04/media-mel-crawfords-rootie-kazootie.html
Here're the same characters done in a quicker style by Mel:
My BG painters have to from time to time paint characters in a cartoony rendered style. This isn't so easy. It seems like you have to have a knack for it. Some of my painters are great at it.
There were a lot of illustrators back in the 50s and 60s who turned character paintings into an art form.
There are lots of styles to do it in. This particular one is really charming, I think.
Note that they aren't over rendered. The shadows are not in logical places either. They are just put down artistically where the artist thinks they will help define the shapes (because there are no cartoon lines bordering the character you need to separate things somehow) and where they look good and FUN.
FUN and CLEAN are two important elements of cartoon character paintings. If you get over rendered and muddy or too realistic, it defeats the purpose.
Golden books are full of great character paintings and so are the covers of old coloring books.
I'm always on the lookout for painters who can do this sort of thing, so if you are planning to be a cartoon illustrator/painter, it would be good to copy these and glean the techniques.
You can find all kinds of cool old cartoon packaging art at this great site: