The preceding discussion of the spectral class-form relationship seems to apply to approximately 80 percent of the brighter extragalactic systems; if those in the highest luminosity category are considered, the percentage is probably greater. Among well-known systems, the most striking exception is probably NGC 205 - one of the fainter companions of the Andromeda Nebula. In spite of its amorphous elliptical structure, its spectral type is considerably earlier than in the K-systems; the principal contributors to the integrated light in the photographic region are probably F-type stars. It is of considerably lower luminosity, however, than the giant ellipticals and spirals, and Baade has pointed out the presence of several dust clouds and a number of blue stars. 8 Also, Baum and Schwarzschild found the anomaly that nebular patches near NGC 205 and near M 31 have the same color, despite a presumed membership in two different stellar populations. 9
This investigation was begun while one of us (W.W.M.) was an Alexander F. Morrison Research Associate at the Lick Observatory, and was continued while he was Visiting Professor at the California Institute of Technology. He wishes to make grateful acknowledgment for facilities and plate material made available by Directors I. S. Bowen of the Mount Wilson and Palomar Observatories and C. D. Shane of the Lick Observatory. He is also indebted to Dr. G. H. Herbig for help in obtaining Crossley spectrograms of M 31, and to Drs. W. Baade and A. R. Sandage for discussions on the subject of classification of galaxies. The research was supported in part by a grant (to W.W.M.) by the Office of Naval Research.