36 THE TONGUES OF WOODPECKERS. 
particular kind of food which could be best obtained by some special 
adaptive feature would naturally 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 proceeding to the modifications of the tongue itself. 
The hyoid is so constructed as to combine the two characters of length 
and strength that are needed for extensile purposes. 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 being absent, 
nor have any indications of this bone been found even in very young 
specimens. The cerato-branchials aud epi-branchials are variable, 
especially the latter, which, as in the Sapsucker (Sphyrapicus), may be 
no longer than in many Passeres, or, as in the Flickers (Colaptes), reach 
the maximum length among birds. The epi-branchials curve up over 
the back of the skull, meet on its summit, and continue on toward 
the forehead. In other long-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, 
pass through the right narial opening, dipping under the nostril, and 
thence continue quite to the tip of the bill, so that in these species the 
extreme possible length of tongue is reached unless some other device 
is resorted to.|_ The cerato-branchials lie side by side when the tongue 
is protruded, and even when it is withdrawn they are posteriorly but 
little separated. The general character of the hyoid is constant in all 
species examined, but, as just stated, the proportions of its component 
parts vary, the extremes being represented by the Sapsucker (Sphyra- 
picus) and Flicker (Colaptes), both of which are figured (P1. IT, figs.1, 3). 
Externally 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 points, 
wuile the basal portion is clothed with smooth, elastic skin, which is 
more or less wrinkled tranversely when the tongue is retracted. The 
skin covering the base of the tongue is reflected, forming a sort of sheath, 
into which the basal part of the tongue is withdrawn when at rest. 
The shape of the patch of minute points, as well as the number and 
character of the points themselves, seems to vary in different species, . 
'Tt would appear that a method is already in uso by which the length of the tongue - 
can be 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 was 
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 Sphyrapicus 
varius, Linn.,” appeared in Proc. Bost. Soc. Nat. Hist., Vol. X, 1864~66, pp. 91-93. 
