- heteropelmousHaving 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.
- schizopelmousHaving the two flexor tendons of the toes entirely separate, and the flexor hallicus going to the first toe only.
- sympelmousOf birds: having the tendons of the deep flexors of the toes blended in one before separating to proceed one to each of the four digits.