The Eastern Bank branch at 155 Dartmouth St. was held up around 12:15 p.m. by a man who showed a note, but no gun.
He's described as being in his mid 20s, 5'6" to 5'8" with very short hair with just a touch of gray, a light goatee - and very large ears. He was wearing an over-sized, purplish L.L. Bean sweatshirt, white sneakers and a burgundy Nike baseball cap.
An Orange Line train was briefly held at Back Bay for a search; he was not found on the train and service resumed.