The Collaborative International Dictionary of English v.0.48:
Lytta \Lyt"ta\ (l[i^]t"t[.a]), n.; pl. Lytt[ae] (-t[=e]). [L., a worm said to grow under the tongue of dogs, and to cause canine madness, fr. Gr. ly`tta, ly`ssa, lit., madness.] (Anat.) A fibrous and muscular band lying within the longitudinal axis of the tongue in many mammals, as the dog. [1913 Webster]