For example, astronomers once referred to spirals like M31 in Andromeda as "late-type galaxies
," because they were thought to evolve from elliptical galaxies.
Falcon-Barroso, R.F.Peletieretal., "Late-type galaxies
observed with SAURON: two-dimensional stellar and emission-line kinematics of 18 spirals, " Monthly Notices of the Royal Astronomical Society, vol.367, no.1, pp.46-78, 2006.
In the 1950s, when the ages of galaxies could be ascertained, it became clear that early- and late-type galaxies
were all approximately the same age; the "tuning fork" was not a manifestation of temporal evolution.