BIRDS OF PARADISE ; 1IORNBILLS 



439 



the beautiful species represented in Fig. 239, the tail filaments 

 are wanting ; but three long filaments proceed from each side of 



FIG. 239. SIX-THREADED B/RD OF PARADISK. 



the neck. In some species, these curious appendages are so 

 disposed, as to give to the Bird the appearance of having four 

 wings. 



397. The last family of the Conirostres is that of BTICERID^:, 

 or Hornbills ; which is remarkable for the very large size of the 

 beak, and also for an extraordinary protuberance with which 

 this is generally surmounted. The beak is arched, and the 

 mandibles toothed at their edges : and when, as is sometimes the 

 case, the protuberance is wanting, the upper mandible itself 

 appears as if swollen or inflated with air. The form of the 

 excrescence varies much with age ; and in very young indivi- 

 duals there is no trace of it. When cut across, it is found to 

 consist of a very loose bony substance ; its interior being tra- 

 versed in every direction by osseous fibres, the interspaces 



