THE TONGUES OF BIRDS. 1015 



snowii iu certain flucbes where members of the same genus even may 

 have quite different tongues, although the direct connection between 

 these differences and the character of the food may not be evident. 

 The tongues of the several si)ecies of the genus Spinus, shown on Plate 

 2, figs. G-10, although constructed on the same general plan, offer con- 

 siderable differences of detail, our common goldfinch, Spinus tristis, 

 being the most highly specialized. The members of the genus Melo- 

 spiza differ even more among themselves, and while Lincoln's sparrow, 

 M. lincolni, may have the tip of the tongue perfectly simple, the song 

 sparrow, M./asci<ita, has the tip quite elaborately fringed. So common 

 a bird as the English sparrow has an aristocratically unique tongue, 

 quite unlike that of any of his relatives on this side of the Atlantic, 

 and still other finches might be adduced to show how great is the range 

 of form in this family.' 



The hooded and the red-breasted mergansers are quite different from 

 each other in their tongues, and yet, so far as we know, there is not 

 sufficient difference in the nature of their food to account for this dis- 

 crepancy; neither does the fact that they have been deemed sufficiently 

 far apart to be placed in two distinct genera signify, for the swifts and 

 swallows show that birds belonging in different suborders even may 

 have very similar tongues. 



The reasons for the modifications of the tongue of the red-breasted 

 merganser are evident; the two rows of sharp, reverted spines on the 

 tongue, which are more nearly teeth than are the serrations of the bill, 

 are to help the bill in catching and swallowing small fishes, while the 

 feathering of the edge may be to aid in capturing still smaller fry, 

 although it is quite as probable a hint of affinity with the other ducks. 

 The tongue of the hooded merganser, which is like that of a duck 

 reversed, is a puzzle whose solution calls for a better knowledge of the 

 food and habits of the bird. 



Finally, not to needlessly multiply instances of differences between 

 the tongues of related species, it may be said that while the petrels 

 have much similarity iu food and habits they differ very materially in 

 the matter of tongues. 



It is next in order to produce circumstantial evidence in the shape of 

 tongues whose peculiarities can be apparently explained by the char- 

 acter of the food or known habits of feeding, iu order to demonstrate 

 the close relations between the two. The number of evident adapta- 

 tions would undoubtedly be very much increased could we observe 

 birds more closely in their native slate, for we might then see the rela- 

 tion some curious tongue bore to some special kind of food, or catch 

 the particular trick of manipulation for which it was adapted. 



Most insectivorous birds swallow their prey without any special 

 manipulation, and this, to a great extent, is true of the fruit eaters. 



' Lucas, Frederic A. The Taxonomic Value of the Tongue iu Birds. The Auk, 

 XIII, No. 2, April, 189G, pp. 109-115. 



