574 B. F. Kingsbury and ]1. I). Jived. 



sowohl, wie bei Triton tseniatus bleibt der Fortsatz nicht lange mit 

 dem knorpeligen Fensterrahmen in knorpeliger Verbindiing; ehe er 

 noch eine Grosse erreicht, schniirt er sich von seineui Mutterboden 

 ab und stellt nun ein freies, auf der Fenestra ovalis auiliegendes 

 Knorpelplattchen dar; das Operculum. * * * Das Operculum ist 

 demnach ein Theil der knorpeligen Ohrhapsel, liervorgewaclisen vom 

 vordern Umfang des ovalen Fensters. Mit dem Hyoidbogen steht es 

 genetisch in heiner Beziehung." Interestingly enough, the descrip- 

 tion and figures indicate that the structure he identified as the Oper- 

 culum was not the Operculum but the Columella. Its shape, con- 

 nection with the anterior border of the fenestra, and its position be- 

 tween artery and vein, leave small doubt of this. The development 

 of the operculum he seems to have entirely missed, and the mode 

 of development advanced by Wiedersheim appears to be more nearly 

 correct, though doubtless chondrification of opercular tissue in the 

 fenestra vestibuli also contributes to its growth. It seems certain 

 that in the growth of the larva both the fenestra and the operculum 

 increase in size, and observation of this enlargement and extension 

 of the rather cleft-like fenestra {vide Gaupp '05, Fig. 350) doubt- 

 less caused Parker to believe that the oval window arose by "dehis- 

 cence," and explains also the mode of origin of the operculum 

 advanced by Semmer and by Wiedersheim. On the other hand, 

 Stohr's contention that the fenestra exists from the beginning as an 

 unchondrified portion of the ear capsule, is without doubt true for 

 Triton as we find it to be for Diemictylus, but describes the origin 

 of the primary rather than the secondary fenestra. Stohr, in a year- 

 old Triton, figures the true operculum. 



Parker's brief statements ('82b, pp. 198, 199, 203, 206, 209) 

 upon the operculum (Stapes) and fenestra vestibuli (ovalis) in 

 lan^al and adult Triton (Triton punctatus) are too indefinite to 

 permit of any conclusions being based on them as to what the con- 

 ditions were. In the adult he comments upon the cartilaginous 

 nature of the operculum (Stapes) and the lack of a stilus (columella). 



Diemictylus viridescens. Little need be said of the conditions in 

 this form since in all essentials it resembles Triton closely. In the 

 transformed salamander (red form) as also in the fully adult (Figs. 



