craniodidymus

dicephalus

 [di-sef´ah-lus] a malformed fetus with two heads; called also bicephalus and derodidymus.

cra·ni·o·did·y·mus

(krā'nē-ō-did'i-mŭs), Conjoined twins with fused bodies but with two heads. See: conjoined twins. [cranio- + G. didymos, twin]