The above is the normal arrangement for an in line transmission system for a conventional rear wheel drive or all wheel drive vehicle. The arrangement for a transverse mounted engine and transmission for a front wheel drive vehicle has the gear box and differential below the engine and consequently the bell housing is a simple cover for the flywheel.
Bell housings take their name from their shape rather than their function. To the technically literate they are better-known as clutch housings or torque converter housings, depending on what they actually house.