Green’s Dictionary of Slang

pot of jelly n.

[rhy. sl.]

the belly.

[US]Maurer & Baker ‘“Aus.” Rhyming Argot’ in AS XIX:3.
[UK]J. Franklyn Dict. Rhy. Sl.
[UK]P. Wright Cockney Dialect and Sl. 99: For ‘belly’ you have the politer choices pot o’ jelly, Auntie Nelly.
[UK]R. Puxley Fresh Rabbit.