Webster’s Revised Unabridged Dictionary · 1913
Rhizocephala
Rhi′zo·ceph′a·la, n. pl. [NL., fr. Gr. ῥίζα root + κεφαλή head.] (Zoöl.) A division of Pectostraca including saclike parasites of Crustacea. They adhere by rootlike extensions of the head. See Illusration in Appendix.