The definitions of the preceding section may be considered a first approximation toward a precise description of the new form classification. The second approximation is furnished by the seventy-two galaxies illustrated in Plates I - XXVII. Of these, all but one (Plate XVI) are from original negatives obtained principally by Edwin Hubble with the 60-inch and 100-inch reflectors of the Mount Wilson Observatory. To limit the number of illustrations, no elliptical systems are reproduced; in addition, preference has been given to S and B systems as nearly flat-on as possible. Preliminary comment on these reproductions is necessary in two respects: the amount of information included in each print, and the photographic gradation of the prints reproduced.