The Collaborative International Dictionary of English v.0.48:

Transmigrate \Trans"mi*grate\, v. i. [imp. & p. p.
   Transmigrated; p. pr. & vb. n. Transmigrating.] [L.
   transmigrare, transmigratum; trans across + migrare to
   migrate. See Migrate.]
   1. To pass from one country or jurisdiction to another for
      the purpose of residence, as men or families; to migrate.
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   2. To pass from one body or condition into another.
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            Their may transmigrate into each other. --Howell.
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