Shells may be the result of the disruption of a small companion in the potential of a much larger galaxy (e.g., Hernquist & Quinn, 1986; Dupraz & Combes, 1985), the disturbance of a disk system in a tidal encounter (Toomre, 1972), an accumulation of resonant stellar orbits (Binney, pers.comm.) or the result of some shock phenomenon in a hot galactic atmosphere (e.g., Williams & Christiansen, 1985; Wilkinson & Bailey, 1985;). To distinguish between these formation mechanisms, CCD direct images in B and R have been obtained at the Anglo-Australian 3.8m telescope for 66 of the 74 galaxies in the range 01
40′ α < 13
46' in the Malin-Carter (1983) catalogue of shell galaxies.