The Collaborative International Dictionary of English v.0.48:

Protracheata \Pro*tra`che*a"ta\, n. pl. [NL. See Pro-, and
   Trachea.] (Zool.)
   Same as Malacopoda.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Malacopoda \Mal`a*cop"o*da\, prop. n. pl. [NL., fr. Gr. malako`s
   soft + -poda.] (Zool.)
   A class of air-breathing Arthropoda; -- called also
   Protracheata, and Onychophora.
   [1913 Webster]

   Note: They somewhat resemble myriapods, and have from
         seventeen to thirty-three pairs of short, imperfectly
         jointed legs, two pairs of simple jaws, and a pair of
         antennae. The trancheae are connected with numerous
         spiracles scattered over the surface of the body.
         Peripatus is the only known genus. See Peripatus.
         [1913 Webster]