8. VISION AND BIOLUMINESCENCE
241
the functions of the upper eyes and the elongated thoracic limbs are
related.
These animals produce light from their photophores and when a
population is luminescing in the depths of the sea then the light which
they produce can often be of greater intensity, within the volume of the
FIG. 85. The development of the photophore in the eye of Euphausia krohnii. A, first
calyptopis ; B, third calyptopis ; C, early furcilia ; D, later furcilia. (After Pierantoni,
1921.)
population, than the light filtering down to them from a midday sun.
Consequently, an examination of the photophores and their functioning
will be made before discussing the levels of light intensity to which the
eyes are sensitive.
Bentheuphausia amblyops has no photophores. All other species,
except those in the genus Xtylocheiron, have ten such organs distributed
241
the functions of the upper eyes and the elongated thoracic limbs are
related.
These animals produce light from their photophores and when a
population is luminescing in the depths of the sea then the light which
they produce can often be of greater intensity, within the volume of the
FIG. 85. The development of the photophore in the eye of Euphausia krohnii. A, first
calyptopis ; B, third calyptopis ; C, early furcilia ; D, later furcilia. (After Pierantoni,
1921.)
population, than the light filtering down to them from a midday sun.
Consequently, an examination of the photophores and their functioning
will be made before discussing the levels of light intensity to which the
eyes are sensitive.
Bentheuphausia amblyops has no photophores. All other species,
except those in the genus Xtylocheiron, have ten such organs distributed