The two that posted the questions are probably looking for canister type filters (common Fram/AC Delco types.)
On all the MB's I've seen, they use what's called a "Full immersion" oil filter, and it's housed inside a jacket. The jacket lid on mine (190D) is heldon by two nuts. The cannister inside is the filter. Make sure you take the time to check around for extra parts, and check over the cannister as well. Most filters you buy come with a rubber and a copper washer. If you have these, use them on the replacement. If not, they go in the spare parts bin.
I'm a fidget when it comes to cars, so I'll give a learned warning. The plastic knob on the power steering pump shows two arrows on it. These are to tighten, and loosen the cap. They are NOT to adjust the steering wheel stiffness, like I originally thought. (It's a fine thread screw, so make sure it's on good, and not just on.) It took me almost a week to get my engine compartment clean after that little fiasco. Doh!!