heteropelmous

from The Century Dictionary.

• In ornithology, peculiar in the disposition of the flexor tendons in the sole of the foot; having that arrangement of these which is peculiar to the trogons or Heterodactyli, in which each of the flexors splits into two tendons, and the flexor hallucis supplies the two posterior toes (first and second digits), while the flexor perforans supplies the two anterior toes.

from the GNU version of the Collaborative International Dictionary of English.

• adjective (Anat.) Having each of the two flexor tendons of the toes bifid, the branches of one going to the first and second toes; those of the other, to the third and fourth toes. See Illust. in Append.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adjective anatomy Having each of the two flexor tendons of the toes bifid, the branches of one going to the first and second toes; those of the other, to the third and fourth toes.