594 Proceedings of the Royal Society of Edinburgh. [Sess. 
obtruded into the fenestra ovalis. By referring to fig. 11 one sees the 
obtrusion of the stapes into the fenestra carried a step farther, and the 
portion enclosed in the fenestra is expanding to form a plate. Contrary to 
Hertwig, the plate and ring portion of the stapes are not developed 
separately. Moreover, we have a gradual shifting of the relative posi- 
Figs. 2 and 3. — S., stapes; A.Cx., auditory capsule, cochlear portion; 
A.Cn., idem-vestibular portion; VII, facial nerve; I. P.P., first 
pharyngeal pouch ; I., incus ; H., hyoid. 
tions of stapes and capsule, the direction of movement being toward the 
latter. 
If Fuchs is right the stapes must first be separated off from the 
auditory capsule and then afterwards push its way back into the 
fenestra. 
Consider again that in the early anlage of the auditory capsule there is 
no indication of a fenestra. The inference is that the capsule in chondri- 
fying simply leaves a space closed by mesenchyme, which later becomes the 
fenestra ovalis. There are a few sections which might indicate, as Fuchs 
