170
WILUAM N. TAVOLGA
It is clear from the neurophysiological studies of Kuiper (1956), Jielof
et al. (1952), Suckling and Suckling (1950, 1964), and others that the
lateral line organ is a displacement detector, with a threshold in the
order of magnitude of about 20 A (Harris and van Bergeijk, 1962). Based
on additional behavioral studies, Dijkgraaf ( 1963a, 1964, 1967) concluded
that these structures primarily respond to “current-like water disturbances.” He also made the point that the lateral line organs are not acoustic
detectors, i.e., they do not respond to a propagated pressure wave. Many
behavioral studies, however, have referred to the lateral line as responding to “sound.” As pointed out by van Bergeijk ( 1 9 6 7 ~ ) ~
Dijkgraaf‘s
original contention (1934) that the lateral line organ can only detect
water motion is perfectly correct. However, the near-field effect is an
inseparable component of acoustic energy, and the entire lateral line system acts as a near-field acoustic detector. The functional similarity of the
inner ear and the lateral line can be illustrated by the following: (1)
Both inner ear hair cells and lateral line organs have a fundamental
structural similarity, even to the polarity of response and arrangement of
kino- and stereocilia (Fig. 20); ( 2 ) both inner ear and lateral line are
supplied by branches of the acoustic nerve; (3) both are essentially displacement detectors (van Bergeijk, 1967a). The lateral line system remained a near-field detector, while the inner ear, by virtue of the proximity of the swim bladder, became a far-field detector (van Bergeijk,
1967a). Both can be considered as acoustic sense organs.
C. Hearing Capacities
1. PSYCHOPHYSICAL STUDIES
In the majority of studies on teleostean auditory capacities, the objective was to determine the upper frequency limits to which the animals
could respond. Attempts have been made in only a few studies to measure
absolute intensity thresholds ( Autrum and Poggendorf, 1951; Diesselhorst,
1938; Kritzler and Wood, 1961; Maliukina, 1960; Poggendorf, 1952; Stetter, 1929; von Boutteville, 1935). In most of these reports, only one or a
few selected frequencies were actually tested. With the exception of the
work of Griffin ( 1950), the intensity measurements were only approximations. Griffin’s determinations were based upon measurements taken with
calibrated hydrophones, amplifiers, and decibel meters.
For most of the ostariophysine fishes tested, the auditory thresholds
were low, in the order of -40 to -60 dB pb, and the most sensitive frequency range was about 100-1500 Hz (Stetter, 1929; Diesselhorst, 1938;
von Boutteville, 1935; Dorai Raj, 1960b; Autrum and Poggendorf, 1951;
WILUAM N. TAVOLGA
It is clear from the neurophysiological studies of Kuiper (1956), Jielof
et al. (1952), Suckling and Suckling (1950, 1964), and others that the
lateral line organ is a displacement detector, with a threshold in the
order of magnitude of about 20 A (Harris and van Bergeijk, 1962). Based
on additional behavioral studies, Dijkgraaf ( 1963a, 1964, 1967) concluded
that these structures primarily respond to “current-like water disturbances.” He also made the point that the lateral line organs are not acoustic
detectors, i.e., they do not respond to a propagated pressure wave. Many
behavioral studies, however, have referred to the lateral line as responding to “sound.” As pointed out by van Bergeijk ( 1 9 6 7 ~ ) ~
Dijkgraaf‘s
original contention (1934) that the lateral line organ can only detect
water motion is perfectly correct. However, the near-field effect is an
inseparable component of acoustic energy, and the entire lateral line system acts as a near-field acoustic detector. The functional similarity of the
inner ear and the lateral line can be illustrated by the following: (1)
Both inner ear hair cells and lateral line organs have a fundamental
structural similarity, even to the polarity of response and arrangement of
kino- and stereocilia (Fig. 20); ( 2 ) both inner ear and lateral line are
supplied by branches of the acoustic nerve; (3) both are essentially displacement detectors (van Bergeijk, 1967a). The lateral line system remained a near-field detector, while the inner ear, by virtue of the proximity of the swim bladder, became a far-field detector (van Bergeijk,
1967a). Both can be considered as acoustic sense organs.
C. Hearing Capacities
1. PSYCHOPHYSICAL STUDIES
In the majority of studies on teleostean auditory capacities, the objective was to determine the upper frequency limits to which the animals
could respond. Attempts have been made in only a few studies to measure
absolute intensity thresholds ( Autrum and Poggendorf, 1951; Diesselhorst,
1938; Kritzler and Wood, 1961; Maliukina, 1960; Poggendorf, 1952; Stetter, 1929; von Boutteville, 1935). In most of these reports, only one or a
few selected frequencies were actually tested. With the exception of the
work of Griffin ( 1950), the intensity measurements were only approximations. Griffin’s determinations were based upon measurements taken with
calibrated hydrophones, amplifiers, and decibel meters.
For most of the ostariophysine fishes tested, the auditory thresholds
were low, in the order of -40 to -60 dB pb, and the most sensitive frequency range was about 100-1500 Hz (Stetter, 1929; Diesselhorst, 1938;
von Boutteville, 1935; Dorai Raj, 1960b; Autrum and Poggendorf, 1951;