The Theory of Sexual Selection. 397 



thereof. The bird, which lives in South America, has 

 a very loud and peculiar call, that can be heard at a 

 distance of two or three miles. The female is dusky- 

 green ; but the adult male is a beautiful white, ex- 

 cepting the extraordinary structure with which we 

 are at present concerned. This is a tube about three 



FIG. ii^.C.tricarunculatus, \ natural size. Copied from the Ibis. 

 The ornamental appendages of the male are represented in a partly 

 inflated condition. 



inches long, which rises from the base of the beak. 

 It is jet black, and dotted over with small downy 

 feathers. The tube is closed at the top, but its cavity 

 communicates with the palate, and thus the whole 

 admits of being inflated from within, when, of course, 

 it stands erect as represented in one of the two draw- 



