  We consider examples of extremal transitions between families of Calabi-Yau
complete intersection threefolds in toric varieties, which are induced by toric
embeddings of one toric variety into the other. We show that the toric map
induced by the linear dual of the embedding induces a birational morphism
between the mirror Calabi-Yau families, and in one case show that it can be
extended to the full mirror transition between mirror families.
  Note: this version uses a different approach to give a shorter proof of the
same result. Also, Lemma 5.8 in the previous versions is definitely wrong.
