in the Whale-bone Whale. 89 
which extends beyond the concave bone, laid open to show 
the termination of the Eustachian tube. 
h. The internal surface of the Eustachian tube. 
i. The opening of the Eustachian tube into the nostril. 
Plate If. 
aa. The internal surface of the concave bone. 
bb. The fatty case in which it is inclosed. 
e. A convexity covered by a thin ligamentous periosteum, 
whose fibres are radiated and connect the membrana tympani, 
as well as the membranous fold/, to the bone. 
d. The hollow formed on the inside of the membrana tym- 
pani. 
e. The external surface of the membrana tympani. 
/. The membrane stretched across from the concave bone 
to the malleus. 
g. Malleus. 
h. Incus. 
i. Stapes. 
k. Cochlea. 
/. Auditory nerve. 
m. The bone connecting the petrous portion to the skull. 
n. A cartilage which had been cut through in preparing the 
cranium ; the part with which the other extremity was con- 
nected has not been ascertained. 
MDCCCXII. 
N 
