MIDTOWN MANHATTAN (WABC) -- An apparently homeless man was struck and critically injured by a bus that did not stop in Midtown.The 51-year-old man was hit by the southbound bus as he crossed Fifth Avenue at 59th Street just before 6 p.m. Tuesday.He was taken to New York-Presbyterian-Cornell Hospital in critical condition.The victim was possibly struck by an MTA bus, based on witness accounts, but investigators were not immediately able to locate a bus that matched the witness description.It was also unclear if the driver was even aware someone had been struck.----------