In the Milky Way, the globular clusters are all very old, and we are accustomed to think of them as the oldest objects in the Galaxy. The clusters cover a wide range of chemical abundance, from near solar down to about [Fe/H] ⋍ −2.3. However there are field stars with abundances significantly lower than −2.3 (eg Bond, 1980); this implies that the clusters formed during the active phase of chemical enrichment, with cluster formation beginning at a time when the enrichment processes were already well under way.

We have obtained 9.5 A resolution spectrophotometry of 10 clusters in M33 (Cf. Christian and Schommer 1982) with the KPNO 4m telescope. Velocities were derived by comparing the cluster spectra to data for template stars, using the “Fourier quotient” technique described by Sargent et al (1977). The positions and velocities of the clusters are shown schematically in Figure 1, where the HI velocity map (Rogstad, et al 1976) is also indicated. We find that the velocities of younger, bluer clusters are more closely matched to the disk-like motion of the gas, while the older redder clusters have more discrepant values (Table I). As shown in Figure 2, Velocity difference, Vel (HI - cluster), varies smoothly with the integrated (B-V), suggesting a slow smooth collapse of M33 to a disk galaxy. This fall, we intend to increase our sample of measured cluster velocities to probe more completely the history of the cluster and disk formation in M33.

SO and smooth-armed Sa galaxies are generic to the Hubble sequence, not formed by environmental stripping.

The contentious title of this discourse was chosen to draw attention to some ideas expressed in a recent publication by Tully, Mould, and Aaronson (1982, hereafter TMA). Two important correlations were discussed in that article. One of those was a correlation between the colors and the intrinsic luminosities or magnitudes of spiral galaxies. The other was a relationship between the color and total mass of disk systems. It is now reasonably accepted that there is also a tight connection between luminosity and total mass.

The main results of a new analysis of the spheroidal (I) and disk (II) components of 98 lenticular and spiral galaxies are :

1. (i) on the average, the magnitude difference between spheroid and total luminosity, ΔmI = BT(I) - BT, varies smoothly along the Hubble sequence from early lenticulars to late-type spirals (Fig. 1);

2. (ii) the trend of ΔmI confirms the concept of the lenticular class as intermediate between E and S classes, not as a parallel sequence;

3. (iii) the large scatter at any given type, σ(ΔmI) ≃ 0.7 mag, is still dominated by measuring and decomposition errors.

4. (iv) The effective surface brightness of the spheroid, μce(I), corrected for galactic extinction AB, decreases by ~2 mag from early to late types, but with a large range (~ 3 mag) at T = const. (Fig. 2a).

5. (v) The effective surface brightness of the disks, corrected for galactic extinction and inclination, μce(II) = μe(II)- AB + 3 log R2s, is almost independent of type, with <μce(II)> ≃ 23.5 for spirals. This implies a corrected central surface brightness μc(0) = μce −1.82 ≃ 21.7, in good agreement with the Freeman rule, but with a large scatter. However, the disks of lenticulars (T< 0) tend to be ~ 0.5 mag fainter than the disks of spirals (Fig. 2b).

6. (vi) The linear effective radii of the spheroidal components are largest, <re (I)> ≳ 1 kpc, among the early type spirals, in agreement with the Hubble classification criterion. The spheroid of lenticulars and late-type spirals tend to be smaller, <re(I)> ≃ 0.5 kpc, but with a large scatter (Fig. 3a). There is no indication of systematic difference between ordinary (SA) and barred (SB) spirals.

7. (vii) The linear effective radii of the disk components are largest <re (I)> ≳ 5 kpc, among intermediate type spirals. The disks of lenticular and late type spirals tend to be smaller (Fig. 3b).

8. (viii) The mean absolute magnitudes of the disk and spheroidal components depend on type (Fig. 4). On the average the disks are brighter (MII ≃ −19.5) among types Sb-Sbc, spheroids (MI ⋍ −19) among types L+ to Sa, but, again, with a large scatter. Disks and spheroids are about equally bright (MI ⋍ MII ⋍ − 19) at stage SO/a (T = 0).

The significant number of dimensions of the manifold is two. Notwithstanding the contamination of the second dimension by projection effects, there are arguments for an intrinsic variation.

The presently fashionable ideas for galaxy formation are reviewed briefly, and it is concluded that the standard isothermal heirarchy fits the available data best. A simple infall picture is presented which explains many of the observed properties of disk galaxies.

The structure and dynamical properties of superclusters (SC's) may help us distinguish between various scenarios for galaxy formation. N-body simulations and analytic estimates show that (contrary to a common belief) a nondissipative pancake scenario can explain the observed flattening of SC's. Then, the disk-halo structure of the Local SC (LSC) and its velocity field suggest that galaxies form before SC's and not necessarily as a result of a dissipative gas collapse to SC pancakes. A confrontation of the simulations with the data indicates that the LSC has collapsed along its short axis only after z~l.

The formation of disc galaxies is generally believed to involve the dissipative collapse of primordial gas clouds, moving in the potentials of dark, self-gravitating massive halos. Until now, most theories have considered only spherically symmetric collapse, with the luminous disc being formed out of a plane of cold gas which is in centrifugal equilibrium. However, it is unlikely that the halo potential will in fact be spherical.

Before theoretical ideas in this subject can be compared with observational data, it is necessary to consider the properties of galaxies that are likely to be relics of their formation. Most astronomers would agree that the list of important parameters should be headed by the total mass M, energy E and angular momentum J. Next on the list should probably be the relative contributions to these quantities from the disc and bulge components of galaxies and denoted D/B for the mass ratio. They can be estimated from the median (i.e. half-mass) radius R, velocity dispersion σ and rotation velocity v of each component, either through the virial theorem or through the luminosity L and an assumed value of M/L. As a first approximation, it is reasonable to suppose that galaxies of a given disc-to-bulge ratio or morphological type form a sequence with mass as the fundamental parameter. The comparison of theory with data is further simplified by considering the extreme cases of ellipticals, with D/B << 1, and late-type spirals, with D/B >> 1. The approach outlined below is to explore the consequences of relaxing in succession the constraints that E, J and M be conserved during the collapse of proto-galaxies. In this article I concentrate on theories that are based on some form of hierarchical clustering because the pancake and related theories are not yet refined enough for a detailed confrontation with observations.