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 82 inches beyond the point 
of the bill. The tongue itself presents the appearance of a slender fleshy 
worm-like body, haying 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 
11 twelfths ; its breadth at the base 21 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 froenula 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 liyal. The tongue itself is in no degree 
extensile or contractile, but has for its solid basis a 
very slender basi-hyal bone, 1 inch 2i twelfths in 
length, terminated by a glosso-hyal bone i an 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 
