“Public toilets were common in ANCIENT ROME. Some could SEAT 80 PEOPLE at one time.”

National Geographic, 5,000 Awesome Facts, Fact #3 on toilets

According to http://www.smithsonianmag.com Roman “toilets” were usually rectangular in size that consisted of a stone slab or wood running like a bench along an interior wall. 

Toilets were called foricae or latrines.

There were regular key-shaped spaced holes that people would sit or squat upon and let their excrement drop down into the canal running underneath that would then travel to the nearest sewer.

A lot of these toilets were have said to be in the kitchen areas so it could double as a convenient place to throw scraps. (http://pbs.org). They were also close to bath houses for they could use the old water to flush out the toilets. 

Potty time would more than likely turn into party time. The distance between the seats was about 12 inches so there was probably a lot of socialization going, and the public bathrooms where news and other stuff could be discussed. Shoot the breeze…

But smelling the public latrines was probably very odoriferous. The windows were small, and there wasn’t good ventilation.

Females seemed to be omitted but probably used them when in dire need.