Heads and Necks 275 
We must pass by all the strange ornaments of horn 
upon the heads of birds, such as the scarlet plate of the 
gallinules, the immense recurved casques of the hornbills, 
the use of which is as yet unknown, unless it be purely 
ornamental. But the impressive helmets of the cassowaries, 
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Fig. 218.—Head of Wild Turkey. 
Fig. 228, demand especial notice in this volume, as being very 
useful adaptations to life in a dense forest. These great 
running birds are the only members of their Sub-class 
which inhabit thickly forested regions, and in speeding 
with great leaps and bounds through the undergrowth, the 
tall, smooth helmet of horn protects the head of the bird 
