  Multimatroids generalize matroids, delta-matroids, and isotropic systems, and
transition polynomials of multimatroids subsume various polynomials for these
latter combinatorial structures, such as the interlace polynomial and the
Tutte-Martin polynomial.
  We prove evaluations of the Tutte-Martin polynomial of isotropic systems from
Bouchet directly and more efficiently in the context of transition polynomials
of multimatroids. Moreover, we generalize some related evaluations of the
transition polynomial of 4-regular graphs from Jaeger to multimatroids. These
evaluations are obtained in a uniform and matroid-theoretic way. We also
translate the evaluations in terms of the interlace polynomial of graphs.
Finally, we give an excluded-minor theorem for the class of binary tight
3-matroids (a subclass of multimatroids) based on the excluded-minor theorem
for the class of binary delta-matroids from Bouchet.
