thing-a-ma-robert (bob) under '78 Gremlin, gas tank vapor return hose...

[Gremlingts@xxxx]

 I was under the GT Saturday, looking for the air-sucking gas line, when I 
spotted a device that isn't a fuel filter, but kinda looks like a galvanized 
silver one, that seems to be inline with the charcoal cannister return line 
to the gas tank. It was mounted in the rear wheel axle well, above the 
pumpkin/pinion gear housing. What the heck is that little thingie, and what 
does it do??? A one-way valve, maybe? Had one line in, one out. Just curious. 

Jerry in Virginia