editor's introduction. 



II 



long as the largely developed bill, and, moreover, its sides are fringed like those of a feather. A 

 tongue of this description may probably be endowed with some delicacy of taste, enabling these birds 

 to appreciate the flavour of the fruits on which they feed. 



Birds of the duck family have the largest tongues. Owing to its fleshy appearance it more nearly 

 resembles the human tongue than even that of the parrot. Birds of this family discriminate their 

 food not by sight, but by the delicate sense of touch with which their tongue is endowed. They 

 thrust their bill into the mud, and from the mouthful thus obtained select, by means of their tongue 

 alone, whatever is fit for food, rejecting the rest. 



The smallest tongues are found in the night-jars and swallows, two groups which at the same 

 time are distinguished by having the largest mouths in proportion to the size of their bodies ; and in 

 this case the design is equally apparent. These birds feed upon living insects captured during their 

 rapid flight, and immediately swallowed whole ; taste is out of the question. A large tongue would 

 only be in the way, and it is therefore reduced to a mere rudiment 



In the preceding examples the length of the tongue never exceeds that of the bill ; but in the 

 case of the woodpeckers it is protrusible to a wonderful extent. On opening the bill of a woodpecker 



W'l /./ — TIT 

 Fig. 9.— THE THROAT OF A FOWL, SHOWING THE PARTS in situ. 



a, the Lower Mandible ; c, the Tongue ; //, m, interior of the Gullet ; i, the Upper Laryn*. 



immediately after it has been killed, the tongue seems of ordinary length, or indeed rather short, and 

 shaped somewhat like the spears used by the Caffres in South Africa, called assagais, pointed at the 

 end and furnished with numerous barbs. (See Fig. 10.) This, however, is only the tip of a very 

 remarkable instrument. If the barbed portion be drawn out of the mouth, a person unacquainted 

 with its nature would think that he had got hold of a very long earthworm that the bird had incau- 

 tiously tried to swallow, but which had stuck in its throat ; hence a tongue of this description is called 

 vermiform. The point in its usual position reposes in the ordinary manner between the mandibles ; 

 the rest is concealed, but is susceptible of extension, at the pleasure of the bird, to four or five times 

 the length of the bill. The act of protrusion is effected by the remarkable structure of the root of the 

 tongue, or more properly of the os hyoides, or bony apparatus whereby it is attached. The posterior 

 prolongations derived from the os hyoides are compactly curved around the back of die skull ; and 

 occasionally they are prolonged forwards to such an extent as actually to reach the nostrils. By 

 means of this somewhat complex arrangement the woodpecker, having broken away the bark of a 

 tree by the powerful strokes of its bill, and thus laid open the retreat of the insects beneath, suddenly 

 darts outs its tongue, spears its prey, and instantly brings the transfixed insect into its mouth. 



The sense of touch must be of very limited utility ; indeed, there seems to be no part of the 

 body of a bird so constructed as to be capable of tactile impressions. The wings, the representatives 

 of hands and arms, are obviously entirely unfit for the exercise of such a function ; neither do the legs 



