COMMON CROSSBILL. 



81 



then bring tlie points of the maxilla? from their crossed or 

 lateral position, to be immediately over each other. In this 

 reduced compass they insinuate their beaks between the 

 scales, and then opening them,— not in the usual manner, 

 but by drawing the inferior maxilla sideways, — force open the 

 scales." 



At this stage of the proceeding the aid of the tongue be- 

 comes necessary ; and this organ is no less admirably adapted 

 for the service required. The os hyoides, or bone of the 

 tonffue, has articulated to its anterior extremity an additional 

 portion formed partly of bone with a horny covering, — figures 

 6 and 7, letter a. In shape it is narrow, about three-eighths 

 of an inch in length, and extends forwards and downwards, 

 the sides curved upwards, the distal extremity shaped like a 

 scoop, somewhat pointed, and thin on both edges, the proxi- 

 mal extremity ending in two small processes elongated up- 

 wards and backwards above the articulation with the bone of 

 the tongue, each process having inserted upon it a slender 

 muscle, 6, figures 6 and 7, extending backwards to the glot- 

 tis, and attached to the os hyoides, which muscles, by their 

 contraction, extend and raise the scoop-like point. Un- 

 derneath the articulation of this horny and grooved append- 

 age is another small muscle, c, figure 7, which is attached at 

 one extremity to the os hyoides, at the other to the moveable 

 piece, and by its action as an antagonist to the upper mus- 

 cles, bends the cutting point downwards and backwards ; 

 while, therefore, the points of the beak press the scale from 

 the body of the cone, the tongue, brought forward by its 

 own muscle (genio hyoideus), is enabled, by the additional 

 muscles described, to direct and insert its cutting scoop un- 

 derneath the seed, and the food thus dislodged is transferred 

 to the mouth ; and it will be seen by a reference to the first 

 figure, that when the mandibles are separated laterally in this 

 operation, the bird has an uninterrupted view of the seed in 



