(sū'dō-ă-sef'ă-lŭs), An apparently headless placental parasitic twin that, however, has rudimentary cephalic structures that can be demonstrated by dissection. [pseudo- + G. a- priv. + kephalē, head]
pseudoacephalus
(soo″dō-ā-sĕf′ă-lŭs) [″ + a-, not, + kephale, head] A parasitic twin that has a rudimentary cranium.