36 THE TONGUES OF WOODPECKERS. 



particular kind of food which could be best obtained by some special 

 adaptive feature would naturalh' have more influence as a modifying 

 agent, even if indulged in for only a short time, than a general diet 

 for a long period, since the one would be positive in its effects, the 

 other negative. 



As the hyoid bone is the framework on which the tongue is built, it 

 will be well to note some of its characteristic features in the wood- 

 peckers before i^roceeding to the modifications of t'he tongue itself. 

 The hyoid is so constructed as to combine the two characters of length 

 and strength that are needed for extensile purjioses. The front of the 

 hyoid is formed by the short, fused cerato-hyals, although a groove, or 

 in some cases a perforation, indicates the double origin of this bone. 

 The basi-hyal is usually very long and very slender and the cerato- 

 branchials abut upon its posterior end, the basi-branchial bein'g absent, 

 nor have any indications of this bone been found even in very young 

 specimens. Tlie cerato-branchials and epi-branchials are variable, 

 especially the latter, Avhich, as in the Sapsucker {S2>hi/ra2)ici(s), may be 

 no longer than in many Passeres, or, as in the ¥\ic]ievi> {Coluptes), reach 

 the maxinuim length among birds. The epi-branchials curve up over 

 the back of tlie skull, meet on its summit, and continue on toward 

 the forehead. In other hmg-tongued birds, as in the humming bird 

 {Trochilus), for example, the apposed bones reach to the base of the 

 bill, but in the longest-tongued. woodpeckers they turn to the right, 

 l>ass through the right narial opening, (lipi>ing under tlie nostril, and 

 thence continue (juite to the tip of the bill, so that in these species the 

 extreme jjossible length of tongue is reached uidess some otlier device 

 is resorted to.' The cerato branehials lie side by side when tlie tongne 

 is protruded, and even when it is withdrawn they are p«>steriofly but 

 little separated. The general character of the hyoi«l is constant in all 

 species examined, but, as just stated, the jiroportions of its component 

 parts vary, the extremes being represented by the Sapsucker {Sphyra- 

 pic)i>i)n]H\ Flicker {Cr>/</^/r«), both of which are figured (Pi. Ill, figs.l,.'^). 



?]xternally the tongue consists at the tip of a horny portion more or 

 less barbed along the edges; this is followed by a section covered with 

 tough skin bearing on the upper surface a long patch of minute ixniiis, 

 wiiile the basal portion is clothed with smooth, elastic skin, which is 

 more or less wrinkled tranversely when the tongue is retra<ted. The 

 skin covering the base of the tongne is retlecte«l, forming a sort of sheath, 

 into which the basal i»art of the tongue is withdrawn when at rest. 

 The shai»e of the patch of minute jioints, as well as the number and 

 character of the i)oints themselves, seems U) vary in ditlerent species. 



'It would ajipcar that a method is already in use by which the length of the tongue 

 can bo greatly increased, and this is the curling of the free ends of the epi-branchials 

 into a spiral. Although I have never met with a specimen in which the hyoid waa 

 so arranged, both Dr. Bryant and Mr. Wm. Palmer have recorded specimens in which 

 the hyoid encircled the eye. Dr. Bryant's paper, entitled "Remarks on ,'^pliyrapicua 

 varius, Linn.,'' appeared in Proc. Bost. Soc. Xat. Hist., Vol. X, 1864-'G(>, pp. 91-03. 



