PLATE 1 



EXPLANATION OF FIGURES 



A series of schemas to show the relations of the different morphological types 

 of fenestral elements in caudate amphibians. The cross-hatched areas represent 

 columella or portions derived outside the ear capsule. The elements derived 

 from ear capsule are unshaded and represent operculum. Broken lines indicate 

 a fusion of fenestral element and ear capsule. 



19 Larval Amblystoma punctatum. 



20 Adult Amblystoma punctatum. 



21 Adult Diemictylus and Triton. 



22 Adult Gyrinophilus representing the Plethodontidae. 



ABBREVIATIONS 



Ec, ear capsule P.g., palatoquadrate 



7./., isthmus fenestralis Sq., squamosum 



Op., operculum or functional fenestral Sl.c, stylus columellae 



plate of the adult VII., nervus facialis 



M.op., musculus opercularis r.j.VII., ramus jugularis facialis 

 Pl.c, plate portion of columella 



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