IIO Lucas on the Tongues of Birds. [ f^, 



characters, the development of the legs of this great goose being 

 due to its terrestrial habits, while the abandonment of flight had 

 led to the degeneration of the shoulder girdle and the consequent 

 cutting away and smoothing down of its various prominences, 

 causing an appearance of relationship where none existed. 



If habit can thus influence the deeper and more substantial 

 parts of the body, it is only natural to expect that more super- 

 ficial, softer structures would yield still more readily to external 

 influences and adapt themselves to the requirements of daily life. 

 Among such parts is the tongue, which in the majority of birds 

 is so intimately concerned either in the getting of food or in its 

 subsequent manipulation. Just here it will perhaps be best, in 

 sporting parlance, ' to hedge ' a little and to say that I have made 

 only a beginning, and a small one at that, in the study of the 

 tougue of birds, and that I am quite ready to retract my statements 

 in the face of better evidence. At the same time the testimony 

 so far is so completely on one side that it does not seem probable 

 that evidence in rebuttal will be forthcoming. Let it be recalled, 

 too, that it was the externa/ modifications of the tongue which 

 were considered to be due to adaptations to food or feeding. 

 As for the hyoid, its modifications, slight though they are, appear 

 to be partly adaptive and partly morphological. For example, 

 while the tongues of Woodpeckers vary immensely in length, and 

 in the extent and character of their barbs and horny papillae, 

 their underlying hyoids agree in the fusion of the cerato-hyals, 

 the complete absence of a basi-branchial, and the fact that the 

 basi-hyal does not extend to the cerato-branchials 1 which abut 

 squarely upon it. This last might appear a good morphological 

 character were it not apparent that this mode of attaching the 

 cerato-branchials to the basi-hyal is the best possible in a tongue 

 which is used as a spear or probe. And yet we find the same 

 condition in the short tongue of the Rhea, and it is hard to see 

 the adaptation in this case. Also there are many birds, obviously 

 not closely related, whose hyoids are similar, so that we are forced 

 to the conclusion that the value of the hyoid for classification is 

 not very great, and that it must be used with caution. 



1 " These be hard words, my masters," but unavoidable. 



