The Collaborative International Dictionary of English v.0.48:

Percesoces \Per*ces"o*ces\, prop. n. pl. [NL., fr. L. perca a
   perch + esox, -ocis, a pike.] (Zool.)
   An order of fishes including the gray mullets (Mugil), the
   barracudas, the silversides, and other related fishes. So
   called from their relation both to perches and to pikes.
   [1913 Webster]