The Collaborative International Dictionary of English v.0.48:

Heteroscian \Het`er*os"cian\, n. [Gr. ?; ? other + ? shadow: cf.
   F. h['e]t['e]roscien.]
   One who lives either north or south of the tropics, as
   contrasted with one who lives on the other side of them; --
   so called because at noon the shadows always fall in opposite
   directions (the one northward, the other southward).
   [1913 Webster]