Rollulus Bonn., Tabl. Encycl. Meth., i, introd., p. xciii (1790).
Type, Phasianus roulroul Scop.
This genus contains but a single species, remarkable for its bright green colour. There is a thick occipital crest of bristly red feathers; both sexes have a tuft of hair-like bristles from the middle of the forehead ; the tarsus is longer than the middle toe and claw, the hind toe is rudimentary or wanting; the wing is well rounded, the first and tenth primaries about equal and the fifth longest or fourth and fifth subequal; the tail of twelve soft feathers is rounded and just a little longer than half the wing. Sexes not alike.