﻿EXTERNAL ANATOMY. APPENDAGES TO HEAD. 29 



particular purpose this latter structure is intended to 

 answer, it is impossible to form a correct idea. Were 

 it confined to those groups which live upon putrid 

 animal substances, like the vultures, where the naked- 

 ness of the head is almost universal, it might be 

 conjectured that, as the feathers of the head would be- 

 come clotted with gore and putrid particles of the dis- 

 gusting food of these birds, which were not within reach 

 of the cleansing operation of the bill, this covering was 

 desired : but then we find that other birds, feeding only 

 upon seeds and vegetables, like the turkey and the 

 chatterers, have their heads also naked ; not to mention 

 the jabiru, some of the cranes, and the great herons of 

 India. These latter, however, and nearly all the bare- 

 necked Grallatores, feed upon all sorts of things, living 

 or dead, and may be almost considered as the vultures 

 of their own order. 



(38.) The head is frequently ornamented with ap- 

 pendages, either in the shape of horns, wattles, or crests : 

 the first two are composed of fleshy or horny sub- 

 stances ; but the latter, which are the most common, 

 consist of lengthened feathers, which the bird can gene- 

 rally erect or depress at pleasure. Although several 

 birds have horn-like appendages, there is only one which 

 has a real horn : this is the 

 Palamedea {fig. 10.), from 

 the front of whose head 

 issues a long spear-shaped 

 horn, moveable, as we be- 

 lieve, at its root, but per- 

 fectly hard and compact in 

 its substance, and which is 

 used as a means of defence 

 against its enemies. The Buceridce, or hornbills, are 

 remarkable for elevated processes, very much resembling 

 horns, but which are no other than enlargements of 

 the bill : the cassowary and the Guinea-fowl, however, 

 may be said, perhaps, to have true horns, although 

 not of the shape usually understood by the term ; yet 



