President Kennedy rode on the right-hand side of the rear seat with Mrs. Kennedy on his left.[C2-106] Governor Connally occupied the right jump seat, Mrs. Connally the left.[C2-107] Driving the Presidential limousine was Special Agent William R. Greer of the Secret Service; on his right sat Kellerman.[C2-108] Kellerman’s responsibilities included maintaining radio communications with the lead and followup cars, scanning the route, and getting out and standing near the President when the cars stopped. _Motorcycles._--Four motorcycles, two on each side, flanked the rear of the Presidential car. They provided some cover for the President, but their main purpose was to keep back the crowd.[C2-109] On previous occasions, the President had requested that, to the extent possible, these flanking motorcycles keep back from the sides of his car.[C2-110] _Presidential followup car._--This vehicle, a 1955 Cadillac eight-passenger convertible especially outfitted for the Secret Service, followed closely behind the President’s automobile.[C2-111] It carried eight Secret Service agents--two in the front seat, two in the rear, and two on each of the right and left running boards.[C2-112] Each agent carried a .38-caliber pistol, and a shotgun and automatic rifle were also available.[C2-113] Presidential Assistants David F. Powers and Kenneth O’Donnell sat in the right and left jump seats, respectively.[C2-114] The agents in this car, under established procedure, had instructions to watch the route for signs of trouble, scanning not only the crowds but the windows and roofs of buildings, overpasses, and crossings.[C2-115] They were instructed to watch particularly for thrown objects, sudden actions in the crowd, and any movements toward the Presidential car.[C2-116] The agents on the front of the running boards had directions to move immediately to positions just to the rear of the President and Mrs. Kennedy when the President’s car slowed to a walking pace or stopped, or when the press of the crowd made it impossible for the escort motorcycles to stay in position on the car’s rear flanks.[C2-117] The two agents on the rear of the running boards were to advance toward the front of the President’s car whenever it stopped or slowed down sufficiently for them to do so.[C2-118]