Tarsus well feathered in front; outer toes more or less reversible;
claws strong; tail decidedly forked; rectrices pointed but not stiff;
nostril opening oval with a median septum which is not plainly seen
in the dry specimen.
Species.
a1. Larger; wing, more than 160 mm.; feathers of breast tipped with
white. ... pacificus (p. 361)
a2. Smaller; wing, less than 150 mm.; feathers of breast uniform
blackish. ... subfurcatus (p. 362)