314 H. H. WILDER, 



searches of Göppert, this has been shown to be formed in many 

 larval Urodeles indirectly from the original Laryngei, the existence of 

 such transition forms as Siren, Triton, Badylethra etc. where there 

 are lateral interruptions of greater or less extent, renders the re- 

 cognition of this element as a different muscle somewhat doubtful. 



c) In the most of the Anura this ring undergoes great modifi- 

 cation, and gives rise to various muscles, the most constant of which 

 are the Constrictor laryngis, differentiated from its anterior 

 (cardiac) side, and the Compressor laryngis, from its posterior 

 (pharyngeal) side. Other bundles are separated by the growth of 

 surrounding parts, or for the purpose of assisting in the production 

 of special sounds. 



It seems, in conclusion, that the great amount of variation shown 

 by these few laryngeal elements among the different Amphibia sug- 

 gests a line of research in the field of physiological physics which 

 may reward careful study. The amount of variation in the shape of 

 arytaenoids, the shape and position of the vocal chords and variations 

 in the muscles controlling them, the occurrence of sesamoid and other 

 accessory cartilages, the formation of resonance boxes etc. are all 

 moments of interest, the connection between which and the voice pro- 

 duced are, so far as I know, almost unknown. I close this paper 

 with the hope that it may stimulate investigation in this direction. 



Smith College, Northampton, Mass., 

 June 1895. 



