Bell Trap

Any help and professional opinions are greatly appreciated.

Does this look like the remnants of a bell trap to you?

This is located in the basement level laundry room of my home built in 1965. I can feel cool air (and sewer gas) emitting from the drain pipe. The cover was a cast iron grate with no bell attached to the underside. The drain is functioning, however , I am unsure if it is trapped or not. If I pour water in the drain water will sit in the lower portion of the drain for a day or so and dry up. I am thinking it obviously must be plugged. Thank you

if a trap sits for 3 or 4 days with out use, the water will dry up. you have 2 options

either pour a 1/2 gallon of water down the drain every couple of days.
or install a trap primer. that works of of pressure differential. in your line

basically, when you use the faucet, it squirts some water into the trap

It could have been a bell trap but hard to tell. I would think the bucket around the pipe would be a little bigger.

If it was a bell trap and the drain is plugged you wouldn't be getting sewer gases.

Pour several buckets of water or run a hose into it. If it drains and only holds water in the bottom then it's not a bell trap but a p-trap below.

If it is not draining have it cleaned. It's useless if it's plugged.
if you don't need it to be clear and useful, put a plug in it.