Remove back (top) shell from body of crab.  Remove fat from back shell, being careful not to break the bitter gall.  Discard gall and back shells.  Remove fat from body shell, if any.  Save fat & body shells and set aside.  In coup pot fry out salt pork or heat bacon fat or oil; add onion, tomato paste, flour & seasonings.  Cook, stirring constantly, until onions are golden brown.  Crack body shells and add with claws and crab fat to cooking pot; cook and stir 1 minute.  Add 2 quarts boiling water and rice; simmer 2 hours.  Vegetables such as potatoes, carrots and whatever you have may be added.  Serve hot.