FOOT OF THE GOATSUCKER. 261 



or hairs at the sides of the gape, and also in clearing 

 the bird of troublesome insects. 



Thehintthrown out by White is that of a naturalist — 

 of one who seeks a new use for a new form of organ ; 

 the other conjectures hardly deserve that character, as 

 they point at no additional use for the additional 

 structure, inasmuch as there are birds with plain claws 

 which live on similar food, and are more infested by 

 nirmides than the goat-suckers. White's hint points 

 to incpiry, the other conjectures do the reverse — they 

 lead from nature to art. 



The goat-suckers themselves, though otherwise 

 noisy enough, are silent upon this subject ; and as the 

 mode of their preying, from the time at which it 

 usually takes place, is not very open to observation, 

 it is difficult to come at the truth by that means. But, 

 from the time, and, as far as it can be observed, the 

 manner of their feeding, the goat-suckers must feed 

 upon beetles and moths, insects on which there is a 

 considerable quantity of substance not available as 

 food ; and as, though there are some points of resem- 

 blance between goat-suckers and owls, no mention is 

 made of the former returning the elytra of beetles 

 and the wings of moths in castings, as the owls do 

 the indigestible parts of their prey, it is not impro- 

 bable, though certainly not proved, that they may use 

 the pectinated claw in removing the indigestible parts 

 before they swallow the rest. It avails little, how- 

 ever, to speculate upon the use of a structure which 

 we have so limited means of observing ; but we may 

 observe in passing, that though Wilson saw these 

 birds scratching their heads with the pectinated claw, 

 that proves nothing as to the specific use of the pecti- 

 nation, because birds which have not their claws pec- 

 tinated, scratch themselves in a similar manner, and 



