There is plenty on here, Marines don't get their paycheck from the Navy, they get it from DFAS, Marines have their own supply and logistic elements (CLB's, MALS, LOGCOM, etc.), the history you can read for yourself. There is no Marine medical fields, that is correct that the Navy handles all of that (corpsmen, doctors, dentist, etc.)
Maybe some of this is applicable to Royal Marines or some other country, but not the USMC.