^Sof 1 ] Lucas, Tongue of the Cape May Warbler. 141 



THE TONGUE OF THE CAPE MAY WARBLER. 



BY FREDERIC A. LUCAS. 



In seeking to unravel the tangled skein of passerine birds 

 and to straighten out its intermingled loops, the taxonomist has 

 sought to avail himself of every possible character, and, from 

 the development of the embryo to the markings on the egg shell, 

 little has been left untried. 



While the character of the tongue has not been overlooked, 

 comparatively little use has been made of it, partly on account 

 of the time and trouble required for the careful study of this 

 organ, and partly perhaps from a doubt as to its value. In 

 his 'Review of North American Birds' Prof. Baird, in treat- 

 ing of the family Sylvicolidae, compared the tongues of several 

 species of this group with those of several species of Coare- 

 bidaa, drawing particular attention to the tongue of Dendroica 

 tigrlna and, mainly on this character, basing the genus 

 Perissoglossa . 



Quite recently Dr. Gadow, in his paper on the 'Structure of 

 Certain Hawaiian Birds,' has laid considerable stress upon the 

 shape and structure of the tongue, using it as the principal 

 character of one of his alternative keys to the arrangement of 

 the families of birds therein discussed. Both Prof. Baird and 

 Dr. Gadow have dwelt to some extent on the tongue of the 

 Coerebidae, the one using it to unite these birds with the Sylvi- 

 colidas, the other to ally them with the Drepanididae. 



In this connection arise the questions : What is the exact 

 taxonomic value of the tongue? and how constant is its pattern 

 in any given group? To these I would add another query : To 

 what extent is the food of a bird indicated by the shape of the 

 tongue ? 



It is much easier to ask these questions than to answer them, 

 and I am very far from being ready with a reply ; still, having 

 had occasion to recently examine the tongues of a number of 

 birds, I am at least partly prepared with a response as to my 

 own ideas on the subject. It would seem that the soft parts of 

 birds would naturally be more plastic than the hard, and that 

 while the bone yields more or less to the pull of the muscle and 



