IVORY-BILLED WOODPECKER. 529 



treme 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 longi- 

 tudinal 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 backwards, 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 11 twelfths ; 

 its breadth at the base 2g 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 dififerent from that of Flycatchers, Goatsuckers, Swallows, and such 

 birds as seize on living insects while on wing. The lower mandible is 

 deeply concave 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 aper- 

 ture 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 intus- 

 susception of the membrane covering it, and having two froenula of 

 elastic tissue inserted into the angle of the jaw. Here it may be pro- 

 per to state, that in birds generally the bony elements of the tongue 

 are seven, as may be represented by the accompa- 

 nying 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 com- . 



ing 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, 



VOL. V. L 1 



