THE JOINT m A FOWL'S TONGUE AND ITS VOCAL 

 FUNCTION. By W. AmsLiE Hollis, M.D. 



Whilst investigating the physiology of the 'clocking' of a 

 ^ broody ' hen, as old John Ray called the sound, I recently met 

 with what I believe to be an undescribed structure in the 

 tongue of the common fowl. As it presumably forms an im- 

 portant part of the mechanism producing the cluck, and is 

 interesting from an evolutionary standpoint, I venture to 

 forward this short note to the JourTial If we observe a 

 matronly hen whilst she is quietly convoying her brood through 

 the unknown perils of a country lane, we shall notice that the 

 cluch is really a dissyllable— a ciduek. Furthermore, that the 

 beak is closed whilst the sound is emitted. Finally, that the 

 hyoid apparatus with the larynx ascends at the beginning of 

 the note, to fall immediately afterwards. Now the rationale of 

 these operations is readily explicable if we examine the 

 structural details of the mechanism which ostensibly produces 

 the call. 



The V-shaped hyoid bone has its body prolonged anteriorly 



1/ 



1 



c 

 b 



--"'ssasss*^ 



Fig. 1 . — Dissection showing the tongue of a fowl. ( x 3. ) 



a, lingual cartilage. c c, long tendon of hyo-glossal (depressor) 



h, distal end of hyoid spur. muscle (left). 



d, elevator muscle. e, section through right cornu. 



in the form of a spur (fig. 1, b), which is imbedded in the 

 root of the tongue. The spur ends, as seen in the figure, in a 

 ■cavity, which forms with the lingual cartilage (a) a hinge-joint. 



