THE IVORY-BILLED WOODPECKER. 223 



of the lower mandible, reaches to 2 twelfths of the extreme tip, but at the 

 will of the bird may be exserted so as to extend 3^ inches beyond the point 

 of the bill. The tongue itself presents the appearance of a slender fleshy 

 worm-like body, having a middle longitudinal groove on its upper surface, 

 which is transversely wrinkled, and terminated by a slender tapering bony 

 point, of which the margins and part of the upper surface are covered with 

 acicular prickles, which are in some degree moveable and directed back- 

 wards, but not capable of being bent outwards, much less in the direction of 

 the tip of the tongue. The length of this organ is apparently 2 inches 8 

 twelfths; but if measured from the base of the basi-hyal bone, only 1 inch 

 1 1 twelfths; its breadth at the base 2 J twelfths, slightly tapering to the end 

 of its fleshy part, where it somewhat suddenly contracts, so as to have a 

 breadth of little more than 1 twelfth. The length of the horny tip is 9 

 twelfths. The tongue at the base is entirely destitute of the lobes and 

 papillae which in other birds give it a sagittate appearance; and there is no 

 uro-hyal bone, which in them slips into a groove along the front of the 

 thyroid bone of the larynx. The mouth is of moderate width, its breadth 

 being, as already mentioned, 11 twelfths, it being in this respect very 

 different from that of Flycatchers, Goatsuckers, Swallows, and such birds as 

 seize on living insects while on wing. The lower mandible is deeply con- 

 cave within, wider than the tongue, and covered with mucous membrane 

 until 1 inch 5 twelfths from the point, beyond which it is horny, with a 

 median groove, near the commencement of which is a small aperture for the 

 ducts of the salivary glands. The tongue is capable of being retracted 10 

 twelfths of an inch from the tip of the mandibles, and is then seen to slide 

 into a sheath, formed by an induplication or intussusception of the membrane 

 covering it, and having two frcenula of elastic tissue inserted into the angle 

 of the jaw. Here it may be proper to state, that in birds generally the bony 

 elements of the tongue are seven, as may be represented by the accompany- 

 ing diagram, in which the first or upper piece is 

 named the glosso-hyal, the next the basi-hyal, the 

 third, in the same line, the uro-hyal; the two coming 

 off from the base of the second piece or basi-hyal are 

 the apo-hyal, to each of which is appended another, 

 the cerato-hyal. The tongue itself is in no degree 

 extensile or contractile, but has for its solid basis a 

 very slender basi-hyal bone, 1 inch 2\ twelfths in 



length, terminated by a glosso-hyal bone \ inch in length, but, as already 

 said, has no basal or uro-hyal bone, which, on account of the unusual extent 

 of its motion, would form an impediment. 



From the base of this basi-hyal bone, there proceed backwards and slightly 



A 



