  Following recent considerations of a non-zero value for the vacuum energy
density and the realization that a simple Kantowski-Sachs model might fit the
classical tests of cosmology, we study the qualitative behavior of three
anisotropic and homogeneous models: Kantowski-Sachs, Bianchi I and Bianchi III
universes, with dust and cosmological constant, in order to find out which are
physically permitted. In fact, these models undergo isotropisation, except for
the Kantowski-Sachs model (Omega_{k_{0}}>0) with Omega_{Lambda_{0}}<
Omega_{Lambda_{M}} and for the Bianchi III (Omega_{k_{0}}<0) with
Omega_{Lambda_{0}}<Omega_{Lambda_{M}}, and the observations will not be able to
distinguish between these models and the standard model. If we impose that the
Universe should be very much isotropic since the last scattering epoch (z
approximately 1000), meaning that the Universe should have approximately the
same Hubble parameter in all directions, we are led to a matter density
parameter very close to the unity at the present time.
