The catcher bears more than a passing resemblance to an early incarnation of Porky Pig.
A Boulevardier was someone who frequented stylish boulevards (originally in Paris). A sweet cocktail was also named for this term during the 30's, originating in Paris.
The first Merrie Melodies cartoon to use "Merrily We Roll Along" as its theme. This cartoon also debuts a blue Warner Bros. shield, which would be used until sometime in 1938.
Dizzy Dan is a play on Dizzy Dean a popular baseball player of the time.
Dizzy Dan's (and later Claude's) cackling sounds resemble that of a horse's whinny, a vocal effect supposedly made by Mel Blanc.