Plate IX. 



Fig. GO. The same, . still farther caudad, showing the caudal portion of 

 the fenestral plate of the columella with its inner and outer bony plates. 



Fig. 61. Siren lacertina, adult. Section showing the columella, ceratohyale 

 the hyo-columellar ligament, into which projects the short stilus, and the 

 cartilaginous portion of the ear capsule that forms the perilymphatic prom- 

 inence. 



Fig. G2. The same, a few sections farther caudad. The caudal end of the 

 stilus is in the ligament. The perilymphatic prominence ; position of artery 

 and vein. 



Fig. 03. The same, farther caudad behind the fenestra and showing the 

 caudal portion of the perilymphatic prominence. 



