546 FRANCIS VILLY. 
time chondrification which has hitherto only appeared at the 
proximal end spreads along the whole length (see figs. 15, 
16). The outer end of the columella now expands against 
the tympanic membrane, and the cavity below, by growing 
upwards, causes the cartilage to appear to project through the 
tympanic cavity on to the membrane. ‘Thus we have the 
permanent conditions established. 
It must be noted that the connecting bar between the meso- 
stapedial and the quadrate cartilage chondrifies and persists, 
being present even in the adult. | 
The most interesting point connected with this section applies 
to the homology of the columella. Firstly, it is not part of the 
hyoid arch developmentally ; nor is it part of the mandibular; 
for at its first appearance it is connected with neither. The 
connection that does take place occurs secondarily and is not a 
mere temporary affair, as is shown by its size and permanence. 
It is not to be considered as an embryological but as an adult 
connection. ‘The equivalence of the columella with the hyo- 
mandibular bar, so strenulously maintained by Professor Parker, 
receives no support from these researches; but it seems probable 
that the columella is not only physiologically but morpho- 
logically to be associated with the ear capsule, and with it 
alone. 
