Defn: That division of the Mollusca which includes the bivalve shells, like the clams and oysters; — so called because they have no evident head. Formerly the group included the Tunicata, Brachiopoda, and sometimes the Bryozoa. See Mollusca.
ACEPHALAN
A*ceph"a*lan, n.
Defn: Same as Acephal.
ACEPHALAN
A*ceph"a*lan, a. (Zoöl.)
Defn: Belonging to the Acephala.
ACEPHALI
A*ceph"a*li, n. pl. Etym: [LL., pl. of acephalus. See Acephal.]
1. A fabulous people reported by ancient writers to have heads.
2. (Eccl. Hist.) (a) A Christian sect without a leader. (b) Bishops and certain clergymen not under regular diocesan control.
3. A class of levelers in the time of K. Henry I.
ACEPHALIST
A*ceph"a*list, n.