I believe the fuel tanks vented into both the long tube filled with charcoal and fitted on two round brackets attached to the big X tubes behind the fibreboard bulkhead, and there were small black plastic tubes going down to a blue catch tank located below the battery in front of the left hand fuel tank.
Quite why they were needed, I haven't worked out yet.
I have both somewhere. I suppose to be an original Federal spec car, they need both, and the "Logic Box" connected to the seat belts which stops the starter motor working unless the seat belts are fastened, and the car also needs the two long bent tubes going from the inlet to the cast iron exhaust manifold.
With all this crap attached to the car, the "Keep it Simple, Keep it Light" philosophy of constructing a Lotus seems to have disappeared under a Federal rule book around 1973/4.