Acephalus

[ah-sef -al-us) [d priv.; keoo.7.7], head]. I. A species of omphalos i tic monsters characterized by complete absence of the head and usually of the upper extremities. Itis the commonest condition among the omphalos i tes. 2. A variety of the foregoing 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. Acervulus, or Acervulus cerebri [as-erfvu-lus ser’-e-bri). Concretionary matter near the base of the pineal gland, consisting of alkaline phosphates and carbonates, with amyloid matter; brain-sand. 24