Carburettor pipe query

[Patrick Garland]

Hi, I was checking oil etc under the bonnet today and noticed that a pipe had fallen off part of my carburettor. I put the pipe back on but the end is split so will probably fall off again. Out of curiosity I thought I would follow the pipe to see where it went.
It goes down in the engine compartment and then back under the car and stops at the bracket that supports the gearbox. It is open ended and the pipe actually looks as though it's been roughly cut. Does anyone know where it is supposed to terminate or is this normal?
I had a quick look in the haynes manual and it does say that there is a vent on the carburettor, so maybe this is the vent. I am very inexperienced in technical stuff so this was a bit puzzling.
It's a 230K engine, 2.3, 240DL 1989.
Thanks in advance.
Patrick