orbitopagus

or·bi·top·a·gus

(ōr'bi-top'ă-gŭs),
Unequal conjoined twins in which the parasite, usually very imperfectly developed, is attached at an orbit of the autosite. See: conjoined twins.
Synonym(s): teratoma orbitae
[L. orbita, orbit, + G. pagos, something fixed]

orbitopagus

(or″bĭ-tŏp′ă-gŭs) [L. orbita, track, + Gr. pagos, thing fixed]
Conjoined twins in which the smaller fetus is attached to the orbit of the larger fetus.