Sept. 14, 1888.J 



SCIENTIFIC NEWS. 



277 



that of mere sensual gratification. It is, indeed, generally 

 covered with a sheath of horn — an evident sign that the 

 sense of taste must be wanting — and it becomes, usually, 

 either an instrument for the capture of living prey, or 

 else one for the extraction of liquid nourishment from 

 honey-bearing flowers. Or, as in the parrots, it may 

 serve as a kind of thumb, and, being opposable to the 

 upper mandible, assist greatly in holding and turning 

 nuts, seeds, or morsels of fruit. And, following the 

 invariable rule of Nature, it is in all such cases con- 

 siderably modified, always in such a manner as best to 

 adapt it to the duties which it is called upon to perform. 

 In the woodpeckers it is especially curious. These, 

 as no doubt most of us know, are birds whose task it is 

 to extract wood-boring insects from their burrows, and 

 in so doing to chip away the unsound wood in which 

 they have made their home ; thus performing a kind of 

 rough surgery which may not impossibly save a slightly- 

 tiiseased tree from death, just as a human operator, by 



barbs, the points of which are directed down the throat. 

 Finally, the saliva, as in the ant-eater among mammals, 

 and in the chameleon among reptiles, is of a 

 highly glutinous consistency. Thus, when the tongue 

 is inserted into the burrow of a wood-boring in- 

 sect — first enlarged by the beak — the tenant, if a 

 small one, adheres to the extremity by reason of the 

 glutinous saliva ; if a larger, the reversed barbs drag it 

 from its retreat. It was formerly asserted that these 

 barbs transfixed the victim, but this is now denied. It 

 may well be, however, that in the case of a powerful 

 insect the sharply-pointed horny tip itself does so, thus 

 killing, or at any rate greatly weakening it, and enabling 

 it to be withdrawn with comparative ease. 



In the night-jars, the martins, the swallows, and the 

 swifts, we find the saliva again playing a very important 

 part in the capture of prey, although the tongue is not 

 developed. In the titmice, however, we have an 

 approach to the woodpecker structure, for the tongue, 



Head of a Woodpecker, showing — 

 a, upper mandible ; 6, lower ditto ; c, if, e, tongue ; f, g, h, hyoid bones. 



cutting away diseased flesh, prolongs or preserves the 

 life of his patient. Therefore do we find, in these birds, 

 that not only does the beak constitute a sort of natural 

 chisel, but that the tongue is specially modified in order 

 that it may perform the actual task of capture ; for that 

 is a work for which the bill itself is obviously unsuited. 

 The one instrument cuts away the wood and exposes 

 the insects to view ; the other must capture them. And 

 therefore modification takes place in a very remarkable 

 ■degree. 



In the first place, the hyoid bones, which support the 

 base of the tongue, and which also serve as an attach- 

 ment for the important muscles of the throat, are greatly 

 lengthened, and, passing over the back of the head, are 

 fastened into the skull just above the right nostril ; and 

 they are accompanied by a narrow strip of muscle, by 

 means of which they are moved. Thus great elasticity 

 at the base of the tongue is provided. That organ itself 

 is extiimely long and slender — almost filamentary, in 

 fact— and is terminated by a long horny appendage, 

 sharply pointed at the extremity, and covered with small 



which isshaped at the extremity something like a "J" pen, 

 is terminated by four reversed spines — two upon either 

 side ; and the saliva is again of a highly glutinous 

 character. Thus these little birds are enabled to extract 

 small insects from the crevices and crannies in the bark of 

 trees, and especially from those in the lower surface of 

 the branches, wherein they are perfectly safe from the 

 attacks of birds in general. 



In the humming-birds, those gems of the feathered 

 race, we once more find the woodpecker structure very 

 closely followed. The hyoid bones are again carried 

 over the top of the skull and terminated upon the fore- 

 head, and the tongue is again long and thread-like 

 (although double nearly to its base), so that it can pene- 

 trate to the base even of the long, bell-shaped flowers 

 which are so plentiful in some of the South American 

 forests, and extract the liquid treasures as well as the 

 small insects which are to be found therein ; for 

 the humming-birds are fond of a mixed diet, and eat 

 both honey and insects. In the honey-eaters themselves, 

 or Meliphagidtz, the tongue is terminated by a tuft of 



