NATURAL THEOLOGY. 263 



III. I shall add one more example, for the sake 

 of its novelty. It is always an agreeable discovery, 



muscle which follows these ligamentous cartilages upon their 

 concave side, arising from the bone of the lower mandible, and so 

 sweeping round with the cartilages and over the skull, to have 

 another tixed point at the upper mandible : these protrude the 

 tongue. Two muscles are seen to arise from the sides of the 

 larjnix, which are the opponents of the last, and retract the tongue. 

 Leaving the other parts of the anatomy, we beg the reader's atten- 

 tion to the action of the muscle C C C, which presents one of 

 those curious instances observed in comparative anatomy, of a 

 mechanism adapted to a particular purpose. The tongue is not 

 only thrust out far by this apparatus, but is shot with great 

 rapidity, in correspondence with its barbed point. This effect 

 is produced by the two extremities of the muscle being fixed 

 points, and the fibres of the muscle itself running on the con- 

 cave side of the cartilagineous bow, so as to form a smaller circle. 

 We require no mathematical demonstration to prove that the 

 tongue must be thrust out to a greater distance than the measure 

 of contraction of the muscle. Let us tie the line of the fishing- 

 rod to its slender top, and pull upon it at the butt : the motion of 

 the top will be very extensive, even when only an inch of the line 

 is drawn through the rings. This is a pretty accurate representa- 

 tion of what takes place by the contraction of this protruding 

 muscle. We have noticed that the upper end of this arch is fixed, 

 the whole motion must therefore be given to the loose extremity 

 in the tongue ; and we cannot but observe that this peculiar arch 

 and muscular ring are adapted for the rapid protrusion of the 

 tongue ; whilst its retraction is produced by a common muscle, 

 that is, a muscle running in a straight course. 



Another curious part of this apparatus is, that a very large 

 gland, Avhich pours out a glutinous matter, is embraced and com- 

 pressed by the action of the circular muscle. This viscid secre- 

 tion bedewing the tongue furnishes an additional means for the 

 bird to pick up insects, such as ants, without the necessity of 

 sticking each with its arrow. Nothing can be more mechanical, or 

 more happily adapted to its purpose, than the whole of this struc- 

 ture, and consequently nothing better suited to strengthen the 



