The Collaborative International Dictionary of English v.0.48:

Hamulus \Ham"u*lus\ (-l[u^]s), n.; pl. Hamuli (-l[imac]). [L.,
   a little hook.]
   1. (Anat.) A hook, or hooklike process.
      [1913 Webster]

   2. (Zool.) A hooked barbicel of a feather.
      [1913 Webster]