90 FACULTIES OP BIRDS. 



they are placed at the sides of the neck. The second 

 pair, commencing from these, run completely over 

 the skull, under the skin, and advancing, from be- 

 hind, forwards, their converging extremities are 

 placed together in a kind of groove, and commonly 

 terminate anteriorly, by an attachment to the right 

 side of the upper jaw. This posterior pair of carti- 

 lages may therefore be compared to steel springs, 

 which actuate the whole organ. This is an elegant 

 example of the great share which mere elasticity 

 possesses in the performance of some functions of 

 the animal economy. When the tongue is to be 

 darted out, the anterior pieces are drawn together, 

 and enter the sheath of the single portion extended 

 for their reception. The tongue is thus lengthened, 

 and admits of being thrust out some inches*." 



The barbs at the tip, like the beard of an arrow, or 

 the witter of a fish-hook, are not the least remarkable 

 part of this curious organ, and unequivocally point 

 out its use. " The bird,'' according to the excellent 

 description of Paley, " having exposed the retreats of 

 the insects by the assistance of its bill, with a motion 

 inconceivably quick, launches out at them this long 

 tongue ; transfixes them upon the barbed needle at 

 the end of it ; and thus draws its prey within its 

 mouth/' " If this be not mechanism," he adds, 

 " what is ? Should it be said that, by continual 

 endeavours to shoot out the tongue to the stretch, 

 the woodpecker species may by degrees have length- 

 ened the organ itself beyond that of other birds, 

 what account can be given of its form, of its tip ? 

 How, in particular, did it get its barb, its dentation ? 

 These barbs, in my opinion, wherever they occur, 

 are decisive proofs of mechanical contrivance f." 



* Comp. Anat. 237. See also Huber de Lingua Picis 

 Stuttgard, 1821 ; Phil. Trans, xix. 509. 

 fNat.Theol.p.251. 



