TABLE
2.2. Auditory, vestibular, and optic nerve distributions
Membrane Auditory
Density
Vestibular VestibularOptic
OpticCommon
Cochlear
length
ganglion
(cells/mm
ganglion
auditory
nerve
auditory vestibular
Species
name
type
(mm)
cells
cochlea)
cells
ratio
fibers
ratio
ratio
Delphinapterus
Beluga
42.0
149,386
3,557
110,500
0.74
leucas
Delphinus
Common
II
34,9
84,175
2,412
4,091
0.05
165,600
1.97
40.48
delphis
dolphin
lnia geoffrensis
Boutu
I
38.2
104,832
2,744
-
-
15,500
0.15
Lagenorhynchus
White-sided
II
33.8
70,000
2,071
-
-
77,500
1.11
obliquidens
dolphin
Lipotes vexillifer
Baiji
-
82,512
-
3,605
0.04
23,800
0.29
6.60
Neophocoena
Finless
-
-
68,198
-
3,455
0.05
88,900
1.30
25.73
phocoenoides
porpoise
Phocoena
Harbor
I
22.5
70,137
3,117
3,200
-
81,700
1.16
25.53
phocoena
porpoise
Physeter catodon
Sperm whale
I
54.3
161,878
2,981
-
-
172,000
1.06
Sousa chinensis
Humpbacked
-
-
70,226
-
3,213
0.05
149,800
2.13
46.62
!'J
dolphin
n
(l)
Stenella attenuata
Spotted
II
36.9
82,506
2,236
-
-
-
-
S'
(')
dolphin
(l)
co
Tursiops truncatus
Bottlenose
II
38.9
96,716
2,486
3,489
0.04
162,700
1.68
46.63
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dolphin
co
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