The Collaborative International Dictionary of English v.0.48:

Nematogene \Nem"a*to*gene\, n. [Nemato- + root of Gr. ? to be
   born.] (Zool.)
   One of the dimorphic forms of the species of Dicyemata, which
   produced vermiform embryos; -- opposed to rhombogene.
   [1913 Webster]