424 



NATURAL HISTORY OF BIRDS. 



clew to the peculiarities of the j)rc.sent family. The special use of the bill as a 

 hammer prevented its spcuialization in the same direction as in the aegithognathous 

 Viirds. 



Parker lias briefly stated the chief saurognathous character to be "the want of 

 fusion of the parts of the jtalate at the mid line." This is especially the case with the 

 vomer, the two lialves of which remain sei)arate even in the adult state. They will 

 l)e seen as two thin styles along the inner margins of the jialatines. The abortive 

 develoi)ment of the maxillo-]ialatines is also very notable. Another feature is the 

 feeble devolopment of the posterior jtart of the palatines, the external posterior angle 

 being usually absent. These jieculiar- 

 ities are well shown in Fig. '212 A 

 and B, which, besides, demonstrates 

 the great general resemblance of the 

 woodpecker's palate and that of the 

 wryneck. 



There are other features in tlio 

 organization of the woodjiccker which 

 indicate an apjiroach to the Passeres 

 besides the palate, for, as we have 

 already remarked, the inanubrial jiro- 

 cess of the breastbone is bifurcate, an<l 

 the pterylosis is (piite ' oscinine,' the 

 wint;-coverts being small and few. 

 ATiothei- character of the wing, which 

 is isomorphic with the corresponding 

 one in the more specialized Passeres, 

 is the reduction in size of the lirst (or, 

 as would be more correct to say, the 

 tenth) primary. 



It would take more space than has 

 been allotted to the jiresent family were we to describe in detail all the structural 

 peculiarities of the group, and, consequently, we are forced to content ourselves with 

 mentioning the curious machinery of the tongue. 



The woodpecker's tongue consists of the same bones as in most other birds, 

 except that the urohyal is entirely absent. The cci'aloliyals are only slightly devel- 

 oped, and early fused together. On the otlicr hand, the basihy.al and both pieces of 

 the horns (thyrohyals) are nnusually slender and extremely eIongat('(l, often so long 

 that their ends reach forw.ard over the ti)]i of the skull nearly to the lip of the bill, in 

 which case the whole ap]iaratus slides forward in the sheath encasing the bones and 

 their muscles, when the tongue is thrust forward ; or the ends of the horns are fastened 

 to the ui)per side of the skull, and their curvature hangs down along the sides of the 

 neck, as seen in the di.agrams. Fig. 213 A and B. Tlie extensor muscles Avliich are 

 attached to the concave curv.ature of the horns and to the mandible, when contraotcd, 

 force the tongue forward a distance corresponding to the flattening of the loop of 

 the horns. By this means the cylindrical and worm-like tongue, which at the end is 

 provided with a ])ointed horny ti]> and barbed with sharjf bristles, can be shot out far 

 beyond the tip of the bill, its flexibility enabling it to penetrate the winding tunnels 

 of the boring insects or the corridors of the industrious ants, on which most wood- 



Fir.. 212. — Piilnte of (.() Drj/obales and (/(i Ji/iij- : mrp, iiinx- 

 illu-jjiilaliia'S ; pi, |ialntinea ; pi, ptcrygoidn ; v, vomer. 



