• (a.) Heterodactylous. • (n.) One of the Heterodactylae.
Het`er·o·dac'tyl adjective (Zoology) Heterodactylous. -- noun One of the Heterodactylæ. 
[adj] - (of bird feet) having the first and second toes directed backward the third and fourth forward
heterodactyl, heterodactylous Having the toes, or one of them, irregular or abnormal, as certain families of birds.
adjective (of bird feet) having the first and second toes directed backward the third and fourth forward
Foot arrangement with toes 1 and 2 pointing backwards, and toes 3 and 4 forwards (e.g. trogons).