The Shapley Concentration or Supercluster (S.C) of galaxies, centered at
A3558 and comprising many clusters and groups of galaxies in the approximate
redshift range z=0.04-0.055 has been recognized as the densest, and one of
the largest concentrations of visible matter within the z < 0.1 Universe.
Several efforts are underway to collect numerous velocities in the region to
map the concentration and evaluate its dynamical state. The central cluster
A3558 has been investigated by Bardelli et al. (1996) with a
pointed ROSAT PSPC observation, leading to a luminosity 
in the energy range 
, within
a radius of 
and a total mass 
within an Abell radius 
. Another member of the Shapley S.C, A3266 has been extensively
studied by Quintana et al. (1996) from observations carried out
both at Las Campanas and Cerro Tololo observatories. A remarkable velocity
substructure is found, interpreted as a tidal outgoing arm reaching from the
center to the northernmost extensions surveyed; the dynamical cluster mass
is estimated at about 
.
The complexity of the region implies that the Abell distance class is not a very good distance indicator (Quintana et al. 1995). In fact, clusters of Abell distance classes 3, 4 and 5 belong to the S.C. It is thus necessary to use redshifts to be able to evaluate the supercluster membership and extension. The membership of several clusters is not yet clear neither is the total extension of the supercluster. As part of our observational work in this area we used the MEFOS spectrograph on one observing session in April 1994. Given the wide field of the MEFOS instrument and its limitation on angular distance between objects, we obtained spectra of a number of galaxies located in the areas of 15 ACO (Abell et al. 1989) clusters that had no, or poorly determined, redshifts as reflected at the time of the observations.
In Sect. 2 we describe the observations and reductions. In Sect. 3 we
present the new velocities and comparisons with published values and
in Sect. 4 we discuss the results for the individual clusters. In
Sect. 5 we summarize the implications of these results for the
supercluster structure (
, is used throughout,
with h=0.5 if needed). For comparison purposes we also observed one MEFOS
field in A1060, and we also report those velocities here.