SECONDARY SEXUAL CHARACTERS 109 



The female is modestly clothed. In the male of the 

 superb bird of paradise (Fig. 56), the mantle behind 

 the neck, when erected, forms a striking ornament ; 

 and on the breast there is a brilliant metallic shield. 

 In the six-shafted bird of paradise (Fig. 57) the 

 male has on its head six feathers with wiry shafts, 



FIG. 57. Six-shafted bird of paradise. 

 (After Elliot.) 



ornaments that occur in no other birds. In the king 

 bird of paradise there are remarkable fans at the 

 sides of the body of the male that can be expanded. 

 The feathers of the fan are emerald-tipped. The 

 two middle feathers of the tail are drawn out into 

 "wires" with a green web at one side of the tip. 



In mammals, secondary sexual differences are very 



