Page:Natural History, Birds.djvu/216

Rh the chin, one on each side of the throat, go completely round the back of the head, and meeting at a point on the forehead, are there inserted into the skull. These branches being highly elastic, free through their whole length, except at the very extremity, and moved by proper muscles both of extension and retraction, are capable of being alternately lengthened and shortened, by which motion the horny tip of the tongue is propelled far beyond the point of the beak, and drawn in again, with a rapidity almost greater than the eye can follow.



Add to this, that there is on each side of the head a very large gland, which secretes a glutinous substance; this gland being embraced and compressed by the action of the muscle that protrudes the tongue, the viscid matter is poured out upon the sides of the tongue as it is thrust forth, and this is sufficiently adhesive to attach small insects, such as ants, small grubs, beetles, &c., which are quickly drawn in and swallowed. But as many of the boring larvæ are too heavy thus to adhere, and would hold on by their tuberculous feet, or by their strong jaws, the capture of such is effected