I 
THE BIRDS OF AUSTRALIA. 
for West African birds, Rhaphidura and Indicapus for Indo-Malay species, with 
Zoonavena for a Madagascar bird, Mearnsia for a Philippine Islands species, and 
Papuanapus for the Papuan endemism. The discontinuous distribution confirms 
the generic separation of these forms as the coloration suggests, indicating 
diverse origin and convergence of tail characters. I find support in a series 
of semi-Spine-tailed birds, all from America, which is divisible into four 
groups : Cypseloides (or Acanthylops)^ Nephoccetes, Aerornis and Chceturellus, 
proving convergence, without the difference of locality as an assistance for 
separation. 
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