The Columella Auris in Ampliibin. 565 



uected by syndesmosis with the under surface of the squamosal near 

 its caudal edge, and doubtless also with the palatoquadrate cartilage 

 as well, though this relation w^as not determined. 



Examination of the condition in the adult of this salamander by 

 means of dissection was made partly because other adult members 

 of this family had been examined in this way. Of three Asiatic 

 genera, Hynobius (Ellipsoglossa nsevius) Salamandrella (kaiser- 

 lingi), and lianidens (Randon sibericus) the "operculum" (colu- 

 mella) is described by Wiedersheim, '77, (503, 519) as a remark- 

 ably large cone of bone wdiose columella [stilus columellre] is closely 

 joined to the lower end of the quadrate. As a result of this intimate 

 connection Wiedersheim called attention to the inevitable shaking 

 of the perilymph that must attend every violent closing of the jaw, — 

 as in the seizing of prey, — an arrangement whose physiological 

 significance it is difficult to comprehend. Granting, however, that 

 as in Ambystoma and Chondrotus, the colnmellar plate is fused with 

 the ear capsule, the difficulty found in the close junction of stilus 

 and palatoquadrate disappears, a fused element not being subject 

 to violent agitation from movement of the jaw, but on the contrary 

 offering a firmer support for the upper end of the quadrate. 



The suggestion is, therefore, made that the columella will be 

 found fused in the other Ambystomidte, including these Asiatic 

 forms, and it is not without some direct evidence. Fig. 65 in Wie- 

 dersheim's monograph ('77) shows the stilus in Ellipsoglossa (Hyno- 

 bius) arising, not from the opercular plate, but from the anterior 

 lip of the fenestra, as in Salamandra. This is also just as he 

 figures it in Ambystoma Weismanni (tigrinum) ('70, Fig. 8), — quite 

 different, as might be expected, from the relations in the Axolotl 

 ('79, Fig. 12). The operculum had been removed. His ('77) Fig. 

 67 (Ranidens), how^ever, suggests a condition such as is found in 

 Cryptobranchus. 



Okajima ('08) has recently given a short description of the col- 

 umella in another member of the family, — Onychodactylus japonicus. 

 An ossified plate, "hollow" in the center with cartilaginous border, 

 he states (p. 353, 354) fits into a lateral fenestra vestibuli. A carti- 

 laginous stilus is connected with the cartilaginous portion of the 



