Recordemos que Atari Jaguar era calificada en aquel entonces por Atari como un sistema 64-bits.
Production of the Jaguar ceased after Atari Corp. merged with JT Storage in a reverse takeover. In a last ditch effort to revive the Jaguar, Atari Corp. tried to play down the other two consoles by proclaiming the Jaguar was the only "64-bit" system. This claim is questioned by some, because the CPU (68000) and GPU executed a 32-bit instruction-set, but sent control signals to the 64-bit graphics co-processors (or "graphics accelerators"). Atari Corp.'s position was that the mere presence of 64-bit ALUs for graphics was sufficient to validate the claim. Design specs for the console allude to the GPU or DSP being capable of acting as a CPU, leaving the Motorola 68000 to read controller inputs. In practice, however, many developers used the Motorola 68000 to drive gameplay logic.
http://en.wikipedia.org/wiki/Atari_Jaguar
Obviamente en realidad no era tal, y suponía un reclamo publicitario de Atari aprovechando como estaba estructurada la consola, pero de ahí viene que artículos como el de este scan lo referencien como sistema 64-bits.