  An alternative Lagrangian definition of an integrable defect is provided and
analyzed. The new approach is sufficiently broad to allow a description of
defects within the Tzitzeica model, which was not possible in previous
approaches, and may be generalizable. New, two-parameter, sine-Gordon defects
are also described, which have characteristics resembling a pair of 'fused'
defects of a previously considered type. The relationship between these defects
and Backlund transformations is described and a Hamiltonian description of
integrable defects is proposed.
