[Dan02]

The black vents are attic ventilation, the one missing would be a bathroom/kitchen fan vent, similar to the one in the bottom of your picture, you can pick them up at pretty much any home depot type store, they'll either be called goosenecks or roof jacks depending on who you talk to.

To be honest that's a pretty stupid place to put it right between the attic vents but that been done.

If you're going to do it yourself you're going to need some tin snips to trim the base to a size which will fit between the black vents, then a caulking gun and some blackjack tar to seal around it because you've had to cut the base down to fit it between the vents.

If you live down south I can probably drop by and pop it in for you quick on Sunday evening and all it'll cost you is a six pack and you'll have to grab the vent for us sometime this weekend. If you're elsewhere in the city I'll have to see how it fits in the schedule.

Also hate to be the bearer of bad news, but it looks like you've got some shingles that have blown off too. If you look just under those black vents there's a shingles lying at an angle to the rest of the roof, it doesn't belong there, that's a cap used to cover to ridges, while it's possible it was left by accident/laziness by your original roofers, it a lot more likely it blew off either your or one of your neighbors houses during one of the wind storms.