Key to the Species. 
A. Larger; wing over 290 mm. 
a\ Dark above and below. 
a". Uniform sooty above ; grey face. 
a"'. Larger ; wing 310-320 mm. . . P. macroptera gouldi, p. 134. 
6'". Smaller ; wing 300-310 mm. . . P. macroptera alhani, p. 139. 
h". Slate-grey above ; distinctive white 
mottlings on the face . . . . P. melanopus, p. 141. 
V. White head and under-surface . . . . P. lessonii leucocephala, p. 153. 
B. Smaller ; wing under 250 mm. ; under- 
surface white. 
c'. Head and back light grey . . . . P. coohii coohii^ p. 166. 
d'. Head black, back dark grey . . . . P. coohii leucoptera, p. 171. 
Note. — ^A s P. mollis cannot be considered an Australian bird, it is not included in 
the above key. 
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