ABSTRACT
NGC 2903 is presented. The color structure within the spiral arms shows a gradient both across the arms, caused by age differences in star-forming regions and by local dust lanes, and across the galaxy, caused by the large-scale dust distribution. In general, all arms show indication of a difference in color from that of the disk, most clearly seen for those in the well-ordered northwest region. The magnitude of this difference depends on the luminosity of the arm. Frequently, among the minor axis, color peaks occur at progressively lager radii in (V-R), (B-V), and (U-B), respectively. The most conspicuous anomaly in the arm structure occurs in the outer northeast arm, which divides into branches, one of which shows the characteristics of only an old population and the other of which shows evidence only of young stars and gas. The well-known "hot spots" in the nucleus show evidence of the presence of blue stars, dust, and gas emission.