The Collaborative International Dictionary of English v.0.48:

Heterotaxy \Het"er*o*tax`y\, n. [Hetero- + Gr. ? an arrangement,
   fr. ? to arrange.] (Biol.)
   Variation in arrangement from that existing in a normal form;
   heterogenous arrangement or structure, as, in botany, the
   deviation in position of the organs of a plant, from the
   ordinary or typical arrangement. Heterotopism

WordNet (r) 3.0 (2006):

heterotaxy
    n 1: any abnormal position of the organs of the body [syn:
         transposition, heterotaxy]