496 PROF. G. B. HOWES ON AN UNRECOGNIZED FEATURE [June 7, 



thyroid cartilage ; in the Amphibia, on the other hand, the epiglot- 

 tidean fold is entirely membranous and in direct connection with the 

 arytenoids, the front faces of which it surmounts (fig. 9, eg.). This 

 difficulty, however, vanishes when it is considered that all recent 

 investit^ation goes to show that the epiglottis is a secondary structure, 

 formed independently of the rest of the larynx, and subject to the 

 greatest variation. Dubois states^ that in Mammals it represents a 

 chondrification of the submucous tissue of the glosso-laryngeal 

 fold, and that it only secondarily comes into connection with the 

 thyroid cwtilage. Clearly, then, the ahsence of a thyroid cartilage 

 in the Amphibia cannot militate against my view. The same author 

 further states that the e))iglottis is present only in Mammals ; but 

 comparison of figs. 1, 1 a, 4, with His's figures of the human embryo 

 referred to, shows that that is certainly not the case. Consideration 

 of the above facts, taken collectively, forces us to the conclusion that 

 the epiglottis may be represented in Anurous Amphibians, and that 

 in a form most nearly realizing, so far as our present knowledge 

 carries us, the initial stage in its development in man himself. 



The interest attaching itself to the discovery of the epiglottis in 

 Amphibia is self-evident, and it opens np questions of no little mor- 

 phological importance. Future investigation must decide how far 

 that which is customarily termed the epiglottis in some Reptiles'* 

 and Birds may or may not correspond with that of Mammals. 



A consideration of the functional significance of this organ, as here 

 described, reveals some interesting facts. Examination of the figures 

 shows at once that the Amphibian epiglottis cannot have much, if any- 

 thing, to do with deglutition. The classical Johannes Miiller was 

 one of the first to insist ^ upon the functional importance of the Mam- 

 malian epiglottis as a voice-organ ; and it is now clearly established^ 

 that while that structure is not essential to deglutition, either of 

 solids or liquids, it is indispensable to the full exercise of the voice, 

 playing a part in phonation of unexpected importance. 



Turning to the Amphibia, it is satisfactory to note that nothing at 

 all comparable to that which I have described is forthcoming among 

 the tailed forms. The epiglottis is clearly appearing among the 

 Anura ; and it becomes a question of the highest interest to inquire, 

 in the knowledge of the above physiological facts, whether its relative 

 development is in any way associated with that of other accessories 

 to the voice, so well known in the males of certain genera. 



Henle long ago called attention {I. c.) to the existence of minor 

 sexual differences in the laryngo-tracheal skeleton in Pipa and other 

 Anura. I liave already shown that traces of both the epiglottis and 

 epilaryngeal folds may be found in females of certain species (figs. 1 c 

 and 3) ; and, on turning my attention to the proposition above named, 

 I was, at first, awarded with unexpected success. In a male of 



1 L. c. p. 186. 



=* Cf. Henle, /. c. pp. 51, 52, and 60, 61. 

 » Handbucb d. Physiologie, 1840. 



^ Walton, " The Function of the Epiglottis," Journ. of Physiology, vol. i. 

 1878-9. 



