THE TONGUES OF BIRDS. 



1011 



the tongue when he says that in drinking sirup the tongue is protruded 

 for half an inch or so and worked rapidly backward and forward. In 

 doing this the tip of the tongue would naturally fill with sirup when 

 protruded, and when the tongue was retracted it would "either be 

 brought far enough back for a vacuum to be formed at the base or 

 liquid could be forced out by pressing the tip against the roof of the 

 mouth as the tongue was 

 again extended. 



The tongues of wood- 

 peckers (Plate 2, figs. 8, 

 9), so far as they have 

 been observed, are con- 

 structed on one plan, 

 being long, slender, and 

 pointed, round or ellipti- 

 cal in cross section, 

 slightly barbed on either 

 side at the tip, and with 

 the upi^er surface cov- 

 ered with backwardly 

 directed spines so min- 

 ute that it needs a mag- 

 nifying glass to properly 

 appreciate them (fig. 7). 

 There are no si)iues at 

 the base of the tongue 

 itself, as in most birds, 

 for the tongue, when re- 

 tracted, is withdrawn 

 into a sheath, or makes 

 its own sheath, tis when 

 a gloved finger is drawn 

 back and the glove 

 doubles upon itself. In 

 most species the tongue 

 is very extensile — the 

 sapsuckers {Sphyrapi- 

 cus) are exceptions — 

 and since, as said in the beginning, the extensibility of the tongue 

 depends on the length of the epibranchials, we find that these are very 

 long, in most cases even longer than the head. Such being tlie case, 

 some special provision has to be made for disposing of the hyoid when 

 the tongue is retracted, and this provision is obtained as follows: The 

 two branches of the hyoid pass up over the back of the skull, coming 

 together at the top, and then (usually) turn to the right and continue 

 onward over the forehead, onward beneath the nostril into the beak, 

 and thence quite to the tip. Still another method is found in some 



Fig. 8. 



