383 Effect of Aleohol and Anesthetics. 
The final persistence of the ampulla-like cavities seems to be 
the rule, these structures being present even when all other por- 
tions of the internal ear are absent. The ampulle of the canals 
are perhaps particularly useful as organs of equilibration in these 
animals, and their stuborn persistence may be indicative of an 
ancient origin and suggests the primary function of the ear as an 
organ of equilibrium. 
i 
¥ 
e: 
& 
we 
"0 
. 
g 
0, 
Py 
Bo! 2.9 
se ES 
SS 
Fic. 16. A horizontal section through the head of a thirteen day embryo from 
a 5.per cent alcohol solution. Two very small and defective eyes have alens be- 
tween them, while more posteriorly two perfectly formed auditory vesicles are seen 
with cartilaginous capsules surrounding them. 
Fic. 17. A section through the auditory region of an eight day embryo treated 
with a4 per cent ether solution. The two auditory vesicles unite dorsally to form 
a huge cavity above the medulla and spinal cord. This embryo also shows an in- 
complete cyclopean eye and spina-befida. ‘sc, semicircular canal; a, auditory 
vesicle, ; ph, pharynx. 
Fig. 18. A section through the auditory vesicle of the embryo shown in fig. 4 
and section fig. 14. The entire auditory vesicle is suppressed except the ampulle 
of the semicircular canals. The right ampulla is larger and shows a papilla with 
hair-like fibers, while the left-ampulla is almost completely closed, yet, it too, shows 
the papilla with projecting hairs. The cartilaginous capsules are small and thus 
adjusted to the tiny ear parts. 
