What/who was in the bag? (SPOILERS!)

What/who was in the bag that was shot by the gangster "James Joyce"?

Was this a person (that occurs in the rest of the movie?) or an animal?


Or perhaps this is irrelevant and is only meant to show that "James Joyce" can kill whoever/whatever he wants to kill? (Btw. Is there any "deep reason" why the gangster is called James Joyce?)


(Sorry for using many "spoiler" tags! These are my first messages, and I like to try them out )