Wow... NBC News has the details:

Rare "mono mono" twin girls born in Ohio were breathing on their own, and their mom said she and her husband were able to hold them on Mother's Day. The babies were born 45 seconds apart, and when the doctors put them next to each other, one grabbed the other's hand, hospital officials told NBC News. The identical twin girls shared the same amniotic sac and placenta. Such births are called monoamniotic, or "mono mono," and doctors say they occur in about one of every 10,000 pregnancies. They were born Friday at Akron General Medical Center and grasped each other's hands when doctors lifted them up for their parents to see after delivery. Sarah Thistlethwaite said babies Jillian and Jenna were removed from ventilators Sunday afternoon after they were able to breathe comfortably. She told The Associated Press that she and her husband Bill both held them for a while on Mother's Day. "It's just hard to put into words how amazing it feels to know the girls are OK," she said. "It's great to know that they're doing so well, and being able to hold them."