Acephalus

(ah-sef f -al-us). 1. A species of omphalos i tic monsters characterized by complete absence of the head and usually of the upper extremities. It is the commonest condition among the omphalos i tes. 2. A variety of the above species marked by the highest form of development. The head is absent, but there is at least one superior extremity, and the thorax is generally fairly well developed.