The Collaborative International Dictionary of English v.0.48:

Jawfoot \Jaw"foot`\, n. (Zool.)
   See Maxilliped.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Maxilliped \Max*il"li*ped\, n. [Maxilla + L. pes, pedis, foot.]
   (Zool.)
   One of the mouth appendages of Crustacea, situated next
   behind the maxillae. Crabs have three pairs, but many of the
   lower Crustacea have but one pair of them. Called also
   jawfoot, and foot jaw.
   [1913 Webster]