Feet zygodactyle, the first and fourth toes directed backward; caeca present; both carotids present; contour-feathers without any aftershaft; dorsal feather-tract divided between the shoulders, and enclosing a lanceolate naked space on the back; an oil-gland present, but nude. Toung hatched naked, and not passing through a downy stage before acquiring feathers. Tail-feathers 10 in number (except in some American genera, which have only 8).
The members of this family have almost a world-wide range, but are most numerous in tropical countries. They vary greatly in nidification and breeding-habits.
The Cuculidae have been variously divided. The Indian forms have by different writers been classed sometimes in two, sometimes in three subfamilies. On the whole the first arrangement appears preferable, as there is no doubt that the Phoenicophainae and
Centropodinae are more closely allied to each other than either of them is to the true Cuckoos. I therefore class them thus :
a. Tarsus feathered anteriorly (only at the base in Coccystes); no accessory femoro-caudal muscle……………….Cuculinae.
b. Tarsus naked; accessory femoro-caudal present……………….Phoenicophainae.