THE IVORY-BILLED WOODPECKER. 225 



hyoid bones, and the action of another pair of muscles, to be presently 

 described. 



The tongue, d, is covered externally with a dense sheath of fibrous tissue. 

 On its lower surface is seen on each side a very slender muscle, commencing 

 at the extremity of the glosso-hyal bone, and running along the whole length 

 of the basi-hyal bone, as well as of the apo-hyal, to be inserted into the 

 cerato-hyal, at the distance of one inch from its base, on the outer edge. 

 The action of this muscle, which has a strong tendon in its whole length, is 

 to bend the tip of the tongue downwards, or to move the horn of the hyoid 

 bone outwards. It may be called the glosso-hyal. It has another tendon 

 running parallel to that mentioned, along its upper edge, of which the action 

 must be to bend the tongue upwards upon the apo-hyal. Besides these 

 muscles, there is another pair, forming the greater part of the fleshy portion 

 of the tongue. They commence at the tip of the basi-hyal bone, or at d, 

 proceed along the upper surface of the tongue, and, after running a course of 

 2|- inches, pass along the anterior surface of the thyroid bone, wind along 

 its edge, and are inserted near the middle surface of the trachea, about its 

 tenth ring. The action of these muscles, alluded to at the end of the last 

 paragraph, and marked n n, is to retract the tongue, when extended, as well 

 as to pull forward the larynx. 



Another pair of very slender muscles, m m, commence upon the edge of 

 the thyroid bone externally of those last described, separate immediately 

 from the trachea, pass directly down the neck in front, under the subcuta- 

 neous muscle and skin, to which they are firmly attached by cellular tissue, 

 and are inserted into the furcular bone about the middle of its length. These 

 muscles, the cleido-tracheales, are not peculiar to Woodpeckers, and have 

 nothing particular to do with the movements of the tongue in those birds. 



Parallel to the lower edge of the jaw, and extending from 4 twelfths 

 anteriorly to its articulation to the junction of its crura, is, on each side, an 

 elongated salivary gland, ff, attached to the jaw by cellular tissue. It is of 

 a yellowish colour, internally parenchymatous, and sends off a duct, which 

 enters the mouth by the aperture already mentioned, at the commencement 

 of the groove in the horny part of the lower mandible. The fluid which it 

 secretes is a glairy mucus, of a whitish colour, which being poured forth 

 around the tip of the tongue covers it with a glutinous substance well 

 adapted for causing the adhesion of any small body to it. 



The Ivory-billed Woodpecker, then, having discovered an insect or larva 

 in a chink of the bark, is enabled by suddenly protruding its tongue, covered 

 with thick mucus, and having a strong slender sharp point furnished with 

 small reversed prickles, to seize it and draw it into the mouth. These 

 prickles are of special use in drawing from its retreat in the wood those 



Vol. IV. 31 



