The Collaborative International Dictionary of English v.0.48:

Semipalmate \Sem`i*pal"mate\, Semipalmated \Sem`i*pal"ma*ted\,
   a. (Zool.)
   Having the anterior toes joined only part way down with a
   web; half-webbed; as, a semipalmate bird or foot. See Illust.
   k under Aves.
   [1913 Webster]