Source : Webster's Revised Unabridged Dictionary (1913)

Holocephali \Hol`o*ceph"a*li\, n. pl. [NL., from Gr. "o`los
   whole + ? head.] (Zo["o]l.)
   An order of elasmobranch fishes, including, among living
   species, only the chim[ae]ras; -- called also {Holocephala}.
   See {Chim[ae]ra}; also Illustration in Appendix.