TONGUE OF THE GREEN WOODPECKER. 59 



case the tip of the tongue would advance to a corresponding 

 distance. Or, the tips of the ceratohyal bones being fixed, or 

 having only a little motion by means of an elastic ligament, 

 these bones may form a very large curve, passing down the 

 sides of the neck to a great distance from the base of the skull, 

 in which case the straightening of this curve would carry for- 

 ward the tip of the tongue. In very many Woodpeckers, the 

 whole ceratohyals with their muscles slide backwards and for- 

 wards in a sheath ; but in this species the tips of these bones 

 being nearly fixed, the protrusion of the tongue is effected by 

 the contraction of the muscle straightening the lower part, or 

 that nearest the mouth, which moves in a sheath. 



A slender muscle proceeds from the lower jaw pretty far 

 forward, on each side, passes backwards, soon attaches itself to 

 the corresponding ceratohyal bone, runs along its whole length, 

 covering or enclosing it, and is attached to its tip. This muscle, 

 bv contractincr, suddenlv thrusts out the toncrue. To the basi- 

 hyal bone in the cylindrical part of the tongue, is attached on 

 each side a muscle, which proceeds downward in front of the 

 bones of the larynx, on passing which it turns aside, winds 

 round the trachea behind, reappears on the other side, and is 

 twice wound round the trachea, to which it finally adheres. 

 This muscle and its fellow, the trachea being fixed by other 

 muscles, draw back the tongue when it has been protruded. 

 In all Woodpeckers these muscles necessarily exist, and are at- 

 tached to the trachea, but are specially twisted round it only in 

 the Green Woodpecker among the European, and the Golden- 

 winged Woodpecker, among the North American species. 



To complete the apparatus, two very large, elongated glands, 

 analogous to the parotid and sublingual in man, secrete a viscid 

 saliva, conveying it each by a single tube, which opens into 

 the mouth, at the angle or point of meeting of the crura of the 

 lower jaw. The fluid thus copiously secreted, fills the place 

 where the tip of the tongue lies when retracted, so that the 

 prehensile bristly tip of that organ is always bedewed with it. 

 Thus a perfectly efiicient instrument for seizing the small and 

 often agile objects on which the Woodpecker feeds, is provided 

 by a very simple contrivance. 



