Gas tank question

[RUFF]

My 74 Challenger has what looks like 4 vent lines coming out of the back of the tank, Can someone tell me the purpose of this?

 

[DetMatt1]

It went something like this.

 

[RUFF]

I see it on mine but wondered why they have those?

 

[DetMatt1]

It was an emission system that prevented fuel vapors from just being into the atmosphere. I think the system was in all the cars by '71.