CHAr. XIII. DECORATION. 73 



elongation wonld impede the act of flight. Yet the 

 beantifully ocellated secondary wing-feathers of the 

 male Argus pheasant are nearly three feet in length ; 

 and in a small African night-jar {Cosmetornis vexilla- 

 rius) one of the primary wing-feathers, during the 

 breeding-season, attains a length of twenty-six inches, 

 whilst the bird itself is only ten inches in length. 

 In another closely-allied genus of night-jars, the shafts 

 of the elongated wing-feathers are naked, except at 

 the extremity, where there is a disc.*^* Again, in 

 another genus of nightjars, the tail-feathers are even 

 still more prodigiously developed ; so that we see the 

 same kind of ornament gained by the males of closely- 

 allied birds, through the development of widely different 

 feathers. 



It is a curious fact that the feathers of birds belons-ino; 

 to distinct groups have been modified in almost exactly 

 the same peculiar manner. Thus the wing-feathers 

 in one of the above-mentioned night-jars are bare 

 along the shaft and terminate in a disc ; or are, as 

 they are sometimes called, spoon or racket-shaped. 

 Feathers of this kind occur in the tail of a motmot 

 {E'umomota su])erciliaris), of a king-fisher, finch, hum- 

 ming-bird, parrot, several Indian drongos {Dicrurus 

 and EdoJius, in one of which the disc stands vertically), 

 and in the tail of certain Birds of Paradise. In these 

 latter birds, similar feathers, beautifully ocellated, 

 ornament the head, as is likewise the case with some 

 gallinaceous birds. In an Indian bustard {Sypheotides 

 auritus) the i'eathers foruiing the ear-tufts, which are 

 about four inches in length, also terminate in discs.*^^ 



« Sclater, in the ' Ibis,' vol. vi. I8G4, p. 114. Livingstone, 'EipeS[^ /CT 

 tion to the Zambesi,' 1865, p. 66. /^^ o 



"^ Jerdoii, 'Birds of India,' vol. iii. p. 620. /<^ rP^ ^^^ 



f03 



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